LIBRARY OF A. KOFOID. b&c-L U.b. THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA PRESENTED BY PROF. CHARLES A. KOFOID AND MRS. PRUDENCE W. KOFOID ERKELEY I2R-\RY NIVERSITY OF CALIFORNIA EARTH CIENCES JBRARY MANUAL OP MINEIjALOGY JIND LITHOLOGT, CONTAINING Tne Elements of tie Science of Minerals and Rods. FOR THE USE OF THE PRACTICAL MINERALOGIST AND GEOLOGIST, AND FOR INSTRUCTION IN SCHOOLS AND COLLEGES. BY JAMES D. DANA. THIRD EDITION. RE-ARRANUKD AND RE-WHITTEN. FOURTEENTH THOUSAND. ILLUSTRATED BY NUMEROUS WOOD-CUTS. NEW YORK : JOHN WILEY & SONS. 1886. COPYRIGHT, 1878, BY JOHN WILEY & SONS. EARTH SCIENCES LIBRARY PEE FACE. THIS Manual in its present shape is new throughout. In the reno- vation it has undergone, new illustrations have been introduced, an'im- proved arrangement of the species has been adopted, the table for the determination of minerals has been reconstructed, and the chapter on rocks has been expanded to a length and fullness that renders it a prominent part of the work. But while modified greatly in all its parts, it is still simple in its methods of presenting the facts in crys- tallography, and in all other explanations ; and special prominence is given, as in former editions, to the more common minerals, with only a brief mention of others. The old practical feature is retained of placing the ores under the prominent metal they contain, and of giving in connection some information as to mines and mining industry. The student is referred to the Text-book of Mineralogy, prepared mainly by Mr. E. S. DANA, for a detailed exposition of the subject of crystallography after Naumann's and Miller's systems, and also of optical mineralogy and other piiysical branches of the science; to the Manual of Determinative Mineralogy and Blowpipe Analysis by Professor GEORGE J. BRUSH, for a thorough work on the use of the blowpipe, and complete tables for the determination of minerals; and to the author's Descriptive Mineralogy and its Appendixes for a comprehensive treatise on all known minerals. JAMES D. DANA. NEW HAVEN, Nov. 1, 1878.. 1923: TABLE OF CONTEXTS. MINERALOGY. MINERALS : General Remarks I I. CRYSTALLIZATION OF MINERALS: CRYSTALLOGRAPHY. 1. General Remarks on Crystallization 4 2. Descriptions of Crystals 8 Explanation of Terms 8 Measurement of Angles ; Goniometers 9 I. SYSTEMS o; \LLIZATIOX: Forms and Struc- ture of Crystals 14 1. Isometric System 1? 2. Dimetric or Tetragonal System 30 3. Trimetric or Orthorhombic System 37 4. Monoclinic System 40 5. Triclinic System 43 6. Hexagonal System 45 1. Hexagonal Section 46 2. Rhombohedral Section 49 7. Distinguishing Characters of the Systems 54 II. TWIN OR COMPOUND CRYSTALS 55 III. CRYSTALLINE AGGREGATES 58 II. PHYSICAL PROPERTIES OF MINERALS. 1. Hardness 63 2. Tenacity 64 3. Specific Gravity 64 4. Refraction and Polarization 66 5. Diaphaneity, Lustre, Color TO 6. Electricity and Magnetism 73 7. Taste, Odor 74 V yj TABLE OF CONTENTS. III. CHEMICAL PROPERTIES OF MINERALS. PAGE 1. Chemical Composition 76 2. Chemical Reactions 81 1. Trials in the Wet Way 81 2. Trials with the Blowpipe 83 IV. DESCRIPTIONS OF MINERALS. 1. Classification 91 2. General Remarks on Ores 92 I. MINERALS CONSISTING OF THE ACIDIC ELEMENTS. 1. Sulphur Group 94 2. Boron Group 97 8. Arsenic Group 98 4. Carbon Group 102 II. MINERALS CONSISTING OF THE BASIC ELEMENTS WITH OR WITHOUT ACIDIC THE SILICATES EXCLUDED. Gold 109 Silver and its Compounds 116 Platinum, Iridium, Ruthenium 124 Palladium 127 Mercury and its Compounds 128 Copper and its Compounds 130 Lead and its Compounds. ., 145 Zinc and its Compounds 154 Cadmium, Tin 159 Compounds of Titanium 162 Cobalt and Nickel and their Compounds 163 Uranium and its Compounds 169 Iron and its Compounds 171 Manganese and its Compounds 188 Compounds of Aluminum 192 Compounds of Cerium, Yttrium, Erbium, Lanthanum and Didymium 201 Compounds of Magnesium 204 Compounds of Calcium 207 Compounds of Barium and Strontium 220 Compounds of Potassium and Sodium 223 Compounds of Ammonium 230 Compounds of Hydrogen , 231 TABLE OF CONTENTS. yij III. SILICA AND SILICATES. 1. SILICA. TAGE Quartz 233 Opal ; 239 2. SILICATES. General Remarks 242 1. Anhydrous Silicates. 1. Bisilicates 243 Pyroxene and Amphibole Group. 244 Beryl, etc ! 252 2. Unisilicates 254 Chrysolite Group 255 Garnet Group 256 Zircon Group 259 Idocrase, Epidote, etc 261 Axinite, lolite , ... 264 Mica Group 265 Scapolite Group 268 Nephelite, Sodalite, Leucite 269 Feldspar Group 272 3. Subsilicates 280 Chondrodite, Tourmaline -. 281 Andalusite, Fibrolite, Cyanite 284 Topaz, Euclase 288 Datolite, Sphene, Staurolite , . . 289 2. Hydrous Silicates. 1. General Section 292 Pectolite, Laumontite, Apophyllite 293 Prelinite, Allophane 295 2. Zeolite Section , 297 Thomsonite, "Natrolite, Analcite, Cliabazite 298 Harmotome, Stilbite, Heulandite 301 3. Margarophyllite Section 804 Talc, Pyrophyllite, Sepiolite SOI Serpentine, Deweylitc, Saponite 307 Kaolinite, Finite 310 Hydromica Group 312 Fanlunite, Hisingerite 315 Chlorite Group 316 yiH TABLE OF CONTENTS. IV. HYDROCARBON COMPOUNDS. PACK 1. Simple Hydrocarbons 321 2. Oxygenated Hydrocarbons 325 3. Asphaltum and Mineral Coals 328 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. 1. Catalogue of American Localities of Minerals 333 2. Brief Notice of Foreign Mining Regions 375 IY. DETERMINATION OF MINERALS. General Remarks 379 Table for the Determination of Minerals. . . 384 ON BOCKS. 1. Constituents of Rocks 409 2. Classes of Rocks 413 3. On some Characteristics of Rocks 414 Use of the Microscope in the Study of Rocks 422 4. Kinds of Rocks 424 1. Fragmental Rocks, exclusive of Limestones 426 2. Limestones or Calcareous Rocks 430 3. Crystalline Rocks, exclusive of Limestones 434 1. Siliceous Rocks 435 2. Mica and Potash-Feldspar Series 437 -8. Mica and Soda-lime Feldspar Series 443 4. Hornblende and Potash-Feldspar Series 444 5. Hornblende and Soda-lime Feldspar Series 446 C. Pyroxene and Soda-lime Feldspar Series 450 7. Pyroxene, Garnet, Epidote, and Chrysolite Rocks, containing little or no Feldspar 452 8. Hydrous Magnesian and Aluminous Recks 453 9. Iron-ore Rocks ... . 455 MINERALOGY. MINERALS, MINERALS are the materials of which the earth consists, and plants and animals the living beings over the surface of the mineral-made globe. A few rocks, like limestone and quartz- yte, consist of a single mineral in more or less pure state ; but the most of them are mixtures of two or more minerals. Through rocks of each kind various other minerals are often distributed, either in a scattered way, or in veins and cavities. Gems are the minerals of jewelry; and ores, those that are im- portant for the metal they contain. Water is a mineral, but generally in an impure state from the presence of other miner- als in solution. The atmosphere, and all gaseous materials set free in volcanic and other regions, are mineral in nature, although, because of their invisibility, seldom to be found among the specimens of mineral cabinets. Even fossils are mineral in composition. This is true of coal which has come from buried plant-beds, and amber from the buried resin of ancient trees, as well as of fossil shells and corals. It is sometimes said that minerals belong to the mineral kingdom, as plants to the vegetable kingdom, and animals to the animal kingdom. Substituting the term inorganic for min- eral, the statement is right ; for, as there are the two kingdoms of life, so there is in Nature what may be called a kingdom, or grand division, including all species not made through the organizing principle of life. But this inorganic kingdom is not restricted to minerals ; it embraces all species made by inor- ganic forces those of the earth's crust or surface, and, also, whatever may form under the manipulations of the chemist. The laws of composition and structure, exemplified in the consti- tution of rocks, are those also of the laboratory. A species mada 2 CHAEACTEES OI MINEEALS. by art, as we term it, is not a product of art, but a result solely of the fundamental laws of composition which are at the basis of all material existence; and the chemist only supplies the favorable conditions for the action of those laws. Mineral species, are then, but a very small part of those which make up the inorganic kingdom or division of Nature. CHARACTERS OF MINERALS. 1. Minerals, unlike most rocks, have a definite chemical composition. This composition, as determined by chemical analysis, serves to define and distinguish the species, and indi- cates their profoundest relations. Owing to difference in com- position, minerals exhibit great differences when heated, and when subjected to various chemical reagents, and these peculi- arities are a means of determining the kind of mineral under examination in any case. The department of the science treat- ing of the composition of minerals and their chemical reactions is termed CHEMICAL MINERALOGY. 2. Each mineral, with few exceptions, has its definite form, by which, when in good specimens, it may be known, and as truly so as a dog or cat. These forms are cubes, prisms, double pyramids, and the like. They are included under plane sur- faces arranged in symmetrical order, according to mathematical law. These forms, in the mineral kingdom, are called crystals. Besides form there is also, as in living individuals, a distinctive internal structure for each species. The facts of this branch of the science come under the head of CRYSTALLOGRAPHIC MINER- ALOGY. 3. Minerals differ in hardness from the diamond at one end of the scale to soapstone at the other. There is a still lower limit in liquids and gases ; but of the hardness or cohesion in this part of the series the mineralogist has little occasion to take note. Minerals differ in specific gravity, and this character, like hardness, is a most important means of distinguishing species. Minerals differ in color ', transparency, lustre, and other opti- cal characters. A few minerals have taste and odor, and when so these char- acters are noticed in descriptions. The facts and principles relating to the above character! are embraced in the department of PHYSICAL MINERALOQ r. In addition to the above-mentioned branches of the science CHARACTERS OF MINERALS. 3 of minerals there is also (4) that of DESCRIPTIVE MINERALOGY, under which are included descriptions of the mineral species ; and (5) that of DETERMINATIVE MINERALOGY, which gives a systematic review of the methods for determining or distinguish- ing minerals. These different branches of ihe subject are here taken up in the following order I. Crystallographic Mineralogy ; 1. Phys- ical Mineralogy; III. Chemical Mineralogy; IV. Descriptive Mineralogy ; V. Determinative Mineralogy. On account of the brief manner in which the subjects are treated in this volume, the heads used for the several parts are, (1) The Crys- tallization of Minerals (2) Physical Properties of Minerals / (3) CJiemical Properties of ^Minerals ; (4) Descriptions o ties / (5) Determination of Minerals. 4 CRYSTALLOGRAPHY. 1. CRYSTALLIZATION OF MINERALS: CRYSTALLOGRAPHY. 1. GENERAL REMARKS ON CRYSTALLIZATION. THE attraction which produces crystals is one of the funda- mental properties of matter. It is identical with the cohesion of ordinary solidification ; for there are few cases outside of the kingdoms of life in which solidification takes place without some degree of crystallization. Cohesive attraction is, in fact, the organizing or structure-making principle in inorganic nature, it producing specific forms for each species of matter, as life does for each living species. A bar of cast-iron is rough and hackly in surface, because of the angular crystalline grains which the iron assumed as solidification took place. A fragment of mar- ble glistens in the sun, owing to the reflection of light from in- numerable crystalline surfaces, every grain in the mass having its crystalline structure. When the cold of winter settles over +he earth in the higher temperate and colder latitudes it is the CRYSTALS OP SNOW. ignal for crystallization over all out-door nature; the air filled with crystal flakes when it snows ; the streams become coated with an aggregation of crystals called ice; and windows are covered with frost because crystal has been added to crystal CEYSTALLOGEAPHY. 5 in long feathered lines over the glass Jack Frost's work being the making of crystals. Water cannot solidify without crystal- lizing, and neither can iron nor lead, nor any mineral material, with perhaps half a dozen exceptions. Crystallization produces masses made of crystalline grains when it cannot make distinct crystals. Granite mountains are mountains of crystals, each particle being crystalline in nature and structure. The lava current, as it cools, becomes a mass of crystalline grains. In fact the earth may be said to have crystal foundations ; and if there is not the beauty of external form, there is everywhere the interior, profounder beauty of universal law : the same law of symmetry which, when external circumstances permit, leads to the perfect crystal with regular facets and angles. Crystals are alone in making known the fact that this law of symmetry is one of the laws of cohesive attraction, and that under it this attraction not only brings the particles of matter into forms of mathematical symmetry, but often develops scores of brilliant facets over their surface with mathematical exact- ness of angle, and the simplest of numerical relations in their positions. Crystals teach also the more wonderful fact that the same species of matter may receive, under the action of this attraction, through some yet incomprehensible changes in its condition, a great diversity of forms from the solid of half a dozen planes to one of scores. The following figures represent a few of the forms in a common species, pyrite, a compound of iron and sulphur. CRYSTALLOGRAPHY. 9. 12. 15. Many more figures might be given for this one species, py- lite. The various forms or planes in any such case have, it is true, mutually dependent relations a fact often expressed by Baying that they have a common fundamental form. But it is none the less a remarkable fact, giving profound interest to the Bubject, that the attraction, while having this degree of unicy in any species, still, under each, admits of the multitudinous variations needed to produce so diverse results. At the time of crystallization the material is usually in a CRYSTALLOGRAPHY. 7 state of fusion, or of gas or vapor, or of solution. In the case of iron the crystallization takes place from a state of fusion, and while the result is ordinarily only a mass of crystalline grains^ distinct crystals are sometimes formed in any cavities. If in the cooling of a crucible of melted lead, bismuth, or sulphur, the crust be broken soon after it forms, and the liquid part within be turned out, crystals will be found covering the interior. Here, also, is crystallization from a state of fusion. When frost or snow-flakes form it exemplifies crystallization from a state of vapor. If a saturated solution of alum, made with hot water, be left to cool, crystals of alum after awhile will appear, and will become of large size if there is enough of the solution. A solution of common salt, or of sugar, affords crystals in the same way. Again, whenever a mineral is produced through the change or decomposition of another, and at the same time assumes the solid state, it takes at once a crystalline structure, if it does not also develop crystals. Further, the crystalline texture of a solid mass may often be changed without fusion : e. g., in tempering steel the bar is changed from coarse-grained steel to fine-grained by heating and then cooling it suddenly in cold water, and vice versa, and this is a change in every grain throughout the bar. Thus the various processes of solidification are processes of crystallization, and the most universal of all facts about miner- als is that they are crystalline in texture. A few exceptions have been alluded to, and one example of these is the mineral opal, in which even the microscope detects no evidence of a crystalline condition, except sometimes in minute portions sup- posed not to be opal. But if we exclude coals and resiris this mineral stands almost alone. Such facts, therefore, do not affect the conclusion that a knowledge of crystallography is of the highest importance to the mineralogist. It is important because 1. A study of the crystalline forms and structure of minerals is a convenient means of distinguishing species the crystals of a species being essentially constant in structure and ia angles. 2. The most important optical characters depend on the crystallization, and have to be learned from crystals. 3. The profoundest chemical relations of minerals are often exhibited in the relations of their crystalline forms. 4. Crystallization opens to us nature at her foundation work *nd illustrates its mathematical character. CRYSTALLOGRAPHY. 2. DESCRIPTIONS OP CRYSTALS. In describing crystals there are two subjects for consider* tion : First, FORM ; and secondly, STRUCTURE. A. FORM, Under form, come up for description, not only the general forms of crystals, but also (1.) The systems of crystallization, that is, the relations ol all crystalline forms, and their classification. (2.) The mutual relations of the planes of a crystal as ascer- tained through their positions and the angles between them. (3.) The distortions of crystals. The perfection of symmetry exhibited in the figures of crystals, in which all similar planes are represented as having the same size and form, is seldom found in nature, and the true form is often greatly disguised by this means. The facts on this point, and the methods of avoid- ing wrong conclusions need to be understood, and these are given beyond. With all such imperfections the angles of crys- tals remain essentially constant. There are irregularities also from other sources. (4.) Twin or compound crystals. With some species twins are more common than regular crystals. (5.) Crystalline aggregates, or combinations of imperfect crystals, or of crystalline grains. Explanations of Terms. The following are explanations of a few terms used in connection with this subject : 1. OctaJiedron. A solid bounded by eight equal triangles. They are equal equilateral triangles in the regular octahedron (Fig. 2, p. 17) ; equal isosceles triangles in the square octahedron (Fig. 17, p. 32) ; equal inequilateral triangles in the rhombic octahedron (Fig. 8, p. 37). 2. Double six-sided pyramids. Double eight-sided pyramids. Double twelve-sided pyramids. Solids made of two equal equilateral six-sided, or eight-sided, or twelve-sided, pyramids placed base to base (Fig. 20, p. 32, and 6, 10, pp. 46, 47). 3. Right prisms. Oblique prisms. Eight prisms are those that are erect, all their sides being at right angles to the base. When inclined, they are called oblique prisms. 4. Interfacial angle. Angle of inclination between two faces or planes. 5. Similar planes. Similar angles. The lateral faces of a square Srism (Fig. 2, p. 14) are equal and have like relations to the axes, and ence they are said to be similar. Solid angles are similar when the plane angles are equal each for each, and the enclosing planes are sev- erally similar in their relations to the axes. 6. Truncated. Bevelled. An edge of a crystal is said to be truncated when it is replaced by a plane equally inclined to the enclosing planes, as in Fig. 13, p. 19 ; and it is bevelled when replaced by two planea CRYSTALLOGRAPHY. 9 equally inclined severally to the adjoining faces. Only edges that are formed by the meeting- of two similar planes can be truncated or bev- elled. The angle between the truncating plane and the plane adjoining it on either side always equals 90 ' plus half the interfacial angle ovei the truncated edge. When a rectangular edge, or one of 90, is trun- cated, this angle is accordingly 135 ( = 90-v45) ; when an edge of 70. it is 125 (=90 + 35) ; when an edge of 140, it is 160 (=90 4- 70). 7. Zme. A zone of planes includes a series of planes having the edges between them, that is, their mutual intersections, all parallel. Thus ir. Fig. 14, on page 6, at top of figure, J2, %}, in front, and two planes below, and others on the back of the crystal are in one zone, a vertical zone. Again, in the same figure, at top, 42, 3|, 22, 42, i2, 42, 22, 3 : |, and the continuation of this series below and over the back of the crystal lie in another vertical zone. And so in other cases, in other directions. All planes in the same zone may be viewed as on the circumference of the same circle. The planes of crystals are generally all comprised in a few zones, and the study of the mathematics of crystals is largely the study of zones of planes. Axes. Imaginary lines in crystals intersecting one another at their centres. Axes are assumed in order to describe the positions of the planes of crystals. In each system of crystallization there is one verti- cal axis, and in all but hexagonal forms there are two lateral axes. Diametral sections. The sections of crystals in which lie any two of the axes. In forms having two lateral axes, there are two vertical diametral sections and one basal. Diametral prisms. Prisms whose sides are parallel to the diametral sections. Measurement of Angles. The angles of crystals are measured by means of instruments called goniometers. These instruments are of two kinds, one the common goniometer, the other, the reflecting goniometer. The common goniometer depends for its use on the very simple prin- ciple that when two straight lines cross one an- other, as A E, C D, in the annexed figure, the parts will diverge equally on opposite sides of the point of intersection (O) ; that is in mathematical lan- guage, the angle A O D is equal to the angle C O E, and A O C is equal to D E. A common form of the instrument is represented in the figure on page 10. The two arms a b, c d, move on a pivot at 0, and their divergence, or the angle they make with one another, is read off on the graduated arc attached. In using it, press up between the edges a o and c 0, the edge of the crystal whose angle is to be measured, and con- tinue thus opening the arms until these edges lie evenly against the faces that include the required angle. To insure accuracy in this respect, hold the instrument and crystal between the eye and the light, and observe that no Jight passes between the arm and the applied faces of the crystal. The arms may then be secured in position by tighten- ing the screw at o ; the angle will then be measured by the distance on the arc from k to the left or outer edge of the arm c d, this edge being in the line of o. the centre of motion. As the instrument stands in tho 10 CRYSTALLOGRAPHY. figure, ib reads 45. The arms have slits at g h, n p, by which the part* a o, co, may be shortened so as to make them more convenient for measuring small crystals. In the best form of the common goniometer the arc is a complete circle, of larger diameter than in the above figure, and the arms a?e separate from it. After making the measurement, the arms are laid upon the circle, with the pivot at the centre of motion inserted in a socket at the centre of the circle. The inner edge of one of the arms is then brought to zero on the circle, and the angle is read off as before. With a Ifttle ingenuity the student may construct a goniometer for himself tbafc will answer a good purpose. A semicircle may be de- scribed on mica or a glazed card, and graduated. The arms might also be made of stiff card for temporary use ; but mica, bone, or metal is better. The arms should have the edges straight and accurately paral- lel, and be pivoted together. The instrument may be used like that last described, and will give approximate results, sufficiently near for dis- tinguishing most minerals. The ivory rule accompanying boxes of mathematical instruments, having upon it a scale of sines for measuring angles, will answer an excellent purpose, and is as convenient as the arc. In making such measurements it is important to have in mind the fact that 1. The sum of the angles about a centre is 360. 2. In a rhomb, as in a square, the sum of the plane angles is 360. In any polygon, the supplements of the Angles equals 360, whatever itte number of sides. For example : in a square, the four angles are each 90, and hence the supplements are 90, and 4x90=360 ; again, in a regular hexagon the six angles are each 120, the supplements are 60, and 6 x 60360. So for all polygons, whether regular or irregular. In measuring the angles it is therefore convenient to take down the supplements of the angles. This principle is conveniently applied in the. measurement of all the angles of a zone of planes around the crystal ; for the sum of all the supplements should be, as abc ve, 380 and if this result is not obtained there is error somewhere. CRYSTALLOGRAPHY. 11 The reflecting goniometer affords a more accurate method of measuring crystals that have lustre, and may be used with those of minute size. The principle on which this instrument is constructed will be understood from the annexed figure, representing a crystal, whose angle a b c is required. The eye, look' inof at the face of the crystal b c, observes a reflected image of m, in the direction P n. On revolving the crystal till a b has the position of b c, the same image will be seen again in tha same direction P n. As the crystal is turned, in this revolution, till a b d has the present position of b c, the angle d b c measures the number of degrees through which it is revolved. But d b c subtracted from 180 C equals the angle of the crystal a b c. The crystal is therefore passed, in its revolution, through a number of degrees equal to the supplement of the required angle. This angle, in the reflecting goniometer of Wollaston, is measured by attaching the crystal to a graduated circle which revolves with it, one form of which is here represented. C is the graduated circle. The wheel, m, is attached to the main ris, and moves the graduated circle together with the adjusted crystal. 12 CBYSTALLOGKAPHY. The wheel, , is connected with an axis which passes through the main axis (which is hollow for the purpose), and moves merely the parts to which the crystal is attached, in order to assist in its adjust- ment. The contrivances for the adjustment of the crystal are at , #, c, d, k. The screws, c, d, are for the adjustment of the crystal, and th slides, a, , serve to centre it. To use the instrument, it may be put on a stand or small table, with its base accurately horizontal, and the table placed in front of a win- dow, six to twelve feet off, with the plane of its circle at right angles to the window. A dark line must then be drawn below the window, near the floor, parallel to the bara of the window, and about as far from the eye as from the window-bar. The crystal is attached to the movable plate k by means of wax, and BO arranged that the edge of intersection of the two planes forming the required angle, shall be in a line with the axis of the instrument. This is done by varying its situation on the plate, or by means of the adjacent screws and slides. When apparently adjusted, the eye must be brought close to the crystal, nearly in contact with it, and on looking into a face, part of the window will be seen reflected, one bar of which must be selected for the trial. If the crystal is correctly adjusted, the selected bar will appear horizontal, and on turning the wheel n, till this bar, aa reflected, is observed to approach the dark line below seen in a direct view, it will be found to be parallel to this dark line, and ultimately to coincide with it. The eye for both observations should be held in precisely the same position. If there is not a perfect coincidence, the adjustment must be altered until this coincidence is obtained. Con- tinue then the revolution of the wheel n. till the same bar is seen by reflection in the next face, and if here there is also a coincidence of the reflected bar with the dark line seen direct, the adjustment is com- plete ; if not, alterations must be made, and the first face again tried. In an instrument like the one figured, the circle is usually graduated to twenty or thirty minutes, and, by means of the vernier, minutes and half minutes are measured. After adjustment, 180 on the arc must be brought opposite 0, on the vernier, y>. The coincidence of the bar and dark line is then to be obtained, by turning the wheel n. When obtained, the wheel m should be turned until the same coincidence ia observed, by means of the next fac$, of the crystal. If a line on the graduated circle now corresponds with on the vernier, the angle is immediately determined by the number of degrees opposite this line. If no line corresponds with 0, we must observe wbich line on the vernier coincides with one on the circle. If it is the 18th on the vernier, and the line on the circle next below on the vernier marki 125, the required angle is 125 18' ; if this latter line marks 125 20 , the required angle is 125 38'. In the better instruments other improved methods of arrangemei;4 are employed ; and in the best, often called Mitscherlich' s goniometer, because first devised by him, there are two telescopes, one for passing a ray of light upon the adjusted crystal, having crossed hair lines in its focus, and the other for viewing it, also with a hair cross. With such an arrangement, the window-bur and dark line are unnecessary, the hair crosses serving to fix the position of the crystal, and the telescopa that of the eye. If the crystal is perfect in its planes, ar4 the adjust- CETSTALLOGRAPHY. 13 ment exact, the measurement, with the best instruments, will give the angle within 10". Other goniometers have only the second of the two telescopes just alluded to, as is the case in the figure on page 11. This telescope gives a fixed position to the eye ; and through it is seen a reflection of some distant object, which may be even a chimney-top. For the measure- ment the object, seen reflected in the two planes successively, is brought each time into conjunction with the hair cross. Exact adjust- ment is absolutely essential, and with an instrument having the two telescopes, the first step in a measurement cannot be taken without it. Only small, well-polished crystals can be accurately measured by the reflecting goniometer. If, when using the instrument without tele- scopes, the faces do not reflect distinctly a bar of the window, the flame of a candle or of a gas-burner, placed at some distance from the crystal, may be used by observing the flash from it with the faces in succession as the circle is revolved. A ray of sun-light from a mirror, received on the crystal through a small hole, may be employed in a similar way. But the results of such measurements will bo only approximations. With two telescopes and artificial light, and with a cross slit to let the light pass in place of the cross hairs of the first of the above-mentioned tele- scopes, this light cross will be reflected from the face of a crystal even when it is not perfect in polish, and quite good results may be obtained. B. STRUCTURE. Structure includes cleavage, a characteristic of crystals intimately connected with their forms and nature. It is the property, which many crystals have, of admitting ot subdivision indefinitely in certain directions, and affording usually even, and frequently polished, surfaces. The direction is always parallel with the planes of the axes, or with others diagonal to these. The ease with which cleavage can be obtained varies greatly in different minerals, and in different directions in the same mineral. In a few species, like mica, it readily yields laminae thinner than paper, and in this case the cleavage is said to be eminent. Others, of perfect cleavage, cleave easily, but afford thicker plates, and from this stage there are all grades to that in which cleavage is barely discernible or difficult. The cleav- age surfaces vary in lustre from the most brilliant to those that are nearly dull. When cleavage in a mineral is alike in two or more directions, that is, is attainable in these directions with equal facility and affords surfaces of like lustre and character or marking, this is proof that the planes in those directions are similar, or have similar relations to like axes. For example, equal cleavage in three directions, at right angles to one another, shows that the planes of cleavage correspond to the faces of the cube ; so equal cleavage in two directions, in a prismatic min- eral, shows that the planes in the two directions are those of a CRYSTALLOGRAPHY. square prism, or else of a rhombic prism ; and if they are at right angles to one another that they are those of the former. This subject is further illustrated beyond. In the following pages (1) the Systems of Crystallization and the Forms and Structure of Crystals are first considered ; next, (2) Compound, or Twin Crystals; and then (3) Crystalline Aggregates. 1. SYSTEMS OF CRYSTALLIZATION: FORMS AND STRUCTURE OF CRYSTALS. The forms of crystals are exceedingly various, while the sys- tems of crystallization, based on their mathematical distinctions, are only six in number. Some of the simplest of the forma under these six systems are the prisms represented in the fol- lowing figures; and by a study of these forms the distinctions 3. 4. of the six systems will become apparent. These prisms are all four-sided, excepting the last, which is six-sided. In them the planes of the top and bottom, and any planes that might be made parallel to these, are called the based planes, and the sides the lateral planes. An imaginary line joining the centres of the bases (c in figures 1 to 8) is called the vertical axis, and the SYSTEMS OF CRYSTALLIZATION. 15 diagonals a and b, drawn in a plane parallel to the base, are the lateral axes. Fig. 1 represents a cube. It has all its planes square (like fig. 9), and all its plane and solid angles, right angles, and the three axes consequently cross at right angles (or, in other 9. 10. 11. 12. noo words, make rectangular intersections) and are equal. It is an example under the first of the systems of crystallization, which system, in allusion to the equality of the axes, is called the Isometric system, from the Greek for equal and measure. Fig. 2 represents an erect or right square prism having all its plane angles and solid angles rectangular. The base is square or a tetragon, and consequently the lateral axes are equal and rectangular in their intersections but, unlike a cube, the verti- cal axis is unequal to the lateral. There are hence, in the square prism, axes of two kinds making rectangular intersections. The system is hence called, in allusion to the two kinds of axes, the bimetric system, or, in allusion to the tetragonal base, the TQ tragonal system. Fig. 3 represents an erect or right rectangular prism, in which, also, the plane angles and solid angles are rectangular. The base is a rectangle (fig. 10), and consequently the lateral axes, connecting the centres of the opposite lateral faces, are un- equal and rectangular in their intersections ; and, at the same time, each is unequal to the vertical. There are hence three unlike axes making rectangular intersections ; and in allusion to the three unlike axes, the system is called the Trimetric sys- tem. It is also named, in allusion to its including erect prisms having a rhombic base, the Orthorhombic system, orthos, in Greek, signifying straight or erect. This rhombic prism is represented in fig. 4. It has a rhom- bic base, like fig. 11 ; the lateral axes connect the centres of the opposite lateral edges ; and hence they cross at right angles and are unequal, as in the rectangular prism. This right rhombio prism is therefore one in system with the right rectangular prism. Fig. 5 represents another rectangular prism, and fig. 16 CRYSTALLOGRAPHY. another rhombic prism ; but, unlike figs. 3 and 4, the prisms are inclined backward, and are therefore oblique prisms. The lat- eral axes (a, b) are at right angles to one another and unequal, as in the preceding system ; but the vertical axis is inclined to the plane of the lateral axes. It is inclined, however, to only one of the lateral axes, it being at right angles to the other. Hence, of the three angles of axial intersection, two are rec- tangular, namely a on 6, and c on b, while one is oblique, ihat is c (the vertical axis) on a. In allusion to this fact, there being only one oblique angle, this system is called the Monoclinic sys- tem, from the Greek for one and inclined. Fig. 7 represents an oblique prism with a rhomboidal base (like fig. 12). The three axes are unequal and the three axial intersections are all oblique. The system is called the Triclinia system, from the Greek for three and inclined. Fig. 8 represents a six-sided prism, with the sides equal, and the base a regular hexagon. The lateral axes are here three in number. They intersect at angles of 60 ; and this is so, whether these lateral axes be lines joining the centres of oppo- site lateral planes, or of opposite lateral edges, as a trial will show. The vertical axis is at right angles to the plane of the three lateral axes, inasmuch as the prism is erect or right. The base of the prism being a regular hexagon, the system is called the Hexagonal system. The systems of crystallization are therefore : I. The ISOMETRIC system : the three axes rectangular in in- tersections ; equal. II. The DIMETRIC or TETRAGONAL system : the three axea rectangular in intersections; the two lateral axes equal, and unequal to the vertical. III. The TRIMETRIO or ORTHORHOMBIC system : the three axea rectangular in intersections, and unequal. IV. The MONOCJLINIC system : only one oblique inclination out of the three made by the intersecting axes ; the three axea unequal. V. The TRICLINIC system : all the three axes obliquely inclined to one another, and unequal. VI. The HEXAGONAL system : the vertical axis at right angles to the lateral ; the lateral .three in number, and intersecting at angles of 60. These six systems of crystallization are based on mathemati- cal distinctions, and the recognition of them is of great value in the study and description of crystals. Yet these distinct iona are often of feeble importance, since they sometimes separate SYSTEMS OF CRYSTALLIZATION. 17 species and crystalline forms that are very close in their rela- tions. There are forms under each of the systems that differ but little in angles from some of other systems : for example, square prisms that vary but slightly from the cubic form ; tri- clinic that are almost identical with monoclinic forms ; hexa- gonal that are nearly cubic. Consequently it is found that the same natural group of minerals may include both trimetric and monoclinic species, as is true of the Hornblende group ; or monoclinic and triclinic, as is the fact with the Feldspar group, and so on. It is hence a point to be remembered, when the affinities of species are under consideration, that difference in crystallographic system is far from certain evidence that any species are fundamentally or widely unlike. L THE ISOMETRIC SYSTEM. 1. Descriptions of Forms. The following are figures of some of the forms of crystals under the isometric system : 2. The first is the cube or hexahedron, ai^eady described. Be- dides the three cubic axes, there are equal diagonals in two other directions ; one set connecting the apices of the diago- nally opposite solid angles, four in number (because the number of such angles is eight), and called the octahedral axes ; and another set connecting the centres of the diagonally opposite 2 18 CRYSTALLOGRAPHY. edges, six in number (because the number of edges is twelve) f and called the dodecahedral axes. Fig. 2 represents the octahedron, a solid contained undef eight equal triangular faces (whence the name from the Greek eight and /ace), and having the three axes like those in the cube. Its plane angles are 60 ; its interfacial angles, that is the incli- nation of planes 1 and 1 over an intervening edge (usually written 1 A 1) = 109 28' ; and 1 on 1 over a solid angle, 70 32'. Fig. 3 is the dodecahedron, a solid contained under twelve equal rhombic faces (whence the name from the Greek for twelve and face). The position of the cubic axes is shown in the fig- ure. It has fourteen solid angles ; six formed by the meeting of four planes, and eight formed by the meeting of three. The interfacial angles (or i on an adjoining i) are 120 ; i on i over a four-faced solid angle =90. Fig. 4 is a trapezohedron, a solid contained under 24 equal trapezoidal faces. There are several different trapezohedrons among isometric crystalline forms. The one here figured, which is the common one, has the angle over the edge -Z?, 131 49', and that over the edge (7, 146 27'. A trapezohedron is also called a tetragonal trisoctahedron, the faces being tetragonal or four-sided, and the number of faces being 3 times 8 (tris, octo, in Greek). Fig. 5 is another trisoctahedron, one having trigonal or three- sided faces, and hence called a trigonal trisoctahedron. Com- paring it with the octahedron, fig. 2, it will be seen that three of its planes correspond to one of the octahedron. The same is true also of the trapezohedron. Fig. 6 is a tetrahexahedron, that is a 4 X 6-faced solid, the faces being 24 in number, and four corresponding to each face of the cube or hexahedron (fig. 1). Fig. 7 is a hexoctahedron, that is a 6 X 8-faced solid, a pyramid of six planes corresponding to each face in the octahedron, as is apparent on comparison. There are different kinds of hexocta- hedrons known among crystallized isometric species, as well as of the two preceding forms. In each case the difference is not in number or general arrangement of planes, but in the angles between the planes, as explained beyond. But these simple forms very commonly occur in combination frith one another ; a cube with the planes of an octahedron and the reverse, or with the planes of any or all of the other kinds above figured, and many others besides. Moreover, all stages between the different forms are often represented among the crystals of a species. Thus between the cube and octahedron, ISOMETRIC SYSTEM, 19 occur the forms shown in figs. 8 to 11. Fig. 12 is a cube; fig. 8 represents the cube with a plane on each angle, equally inclined to each cubic face ; 9, the same, with the planes on the angles more enlarged and the cubic faces reduced in size ; and 8. then 10, the octahedron, with the cubic faces quite small ; and fig. 11, the octahedron, the cubic faces having disappeared altogether. This transformation is easily performed by the student with cubes cut out of chalk, clay, or a potato. It shows the fact that the cubic axes (fig. 12) connect the apices of the solid angles in the octahedron. Again, between a cube and a dodecahedron there occur forma like figs. 13 and 14 ; fig. 12 being a cube, fig. 13 the same> with planes truncating the edges, each plane being equally inclined to the adjacent cubic faces, and fig. 14 another, with these planes on the edges large and the cubic faces small ; and then, when the cubic faces disappear by farther enlargement of the planes on the edges, the form is a dodecahedron, fig. 15. The student should prove this transformation by trial with chalk or Borne other material, and so for other cases mentioned beyond* The surface of such models in chalk may be made hard by a coat of mucilage or varnish. Again, between a cube and a trapezohedron there are the forms 17 and 18 ; 16 being the cube, 17, cube with three planes placed symmetrically on each angle ; 1 8, the same with the cubic faces greatly reduced (but also with small octahedral faces), and 19, the trapezohedron, the cubic faces having disappeared. CRYSTALLOGRAPHY. Again, fig. 20 represents a cube with three planes on each angle, which, if enlarged to the obliteration of the faces of tha cube, become the trigonal trisoetahedron, fig. 21. So again, fig. 16. 17, 22 represents a cube with six faces on each angle, which, if en larged to the same extent as in the last, would become the lex* octahedron, fig. 23. Again, fig. 25 is a form between the octahedron (fig. 24) and dodecahedron (fig. 26) ; and figs. 27 and 28 are forms between the dodecahedron, fig. 26, and trapezohedron, fig. 29. ISOMETRIC SYSTEM. 21 Again, fig. 30 is a form between a cube (fig. 16) and a tetra hexahedron, fig. 31 ; fig. 32, a form between an octahedron, fig. 24, and a tetrahexahedron, fig. 31 ; fig. 33, a form between ai octahedron and a trigonal trisoctahedron, fig. 34 ; fig. 35, a form between a dodecahedron (planes i) and a tetrahexahedron ; fig. 36, a form between the dodecahedron and a hexoctahedron, fig. 37. Fig. 38 represents a cube with planes of both the octahedron nd dodecahedron. 2, Positions of planes with reference to the axes. Lettering Of figures. The numbers by which the planes in the above figures, and others of the work, are lettered, indicate the positions of the planes with reference to the axes, and exhibit the mathematical symmetry And ratios in crystallization. In the figure of the cube (fig. 1) the three axes are represented ; the lateral semi-axis which meets the front planes in the figure is lettered ; that meeting the side plane to the right 6, and the vertical axis c, and the other halves of the same axes respectively -, -&, -c. By a study of the positions of the planes of the 22 CRYSTALLOGRAPHY. cube and other forms with reference to these axes, tho following facti will become apparent. In the cube (fig. 1) the front plane touches the extremity of axis , but is parallel to axes b and c. When one line or plane is parallel to another they do not meet except at an infinite distance, and hence the sign for infinity is used to express parallelism. Employing j, the initial of infinity, as this sign, and writing c, , a, for the semi-axes so lettered, then the position of this plane of the cube is indicated by the expression ie : ib : la. The top and side-planes of the cube meet one axis and are parallel to the other two, and the same expression answers for each, if only the letters , 6, c, be changed to correspond with their positions. The opposite planes have the same expressions, except that the c, &, a will refer to the opposite halves of the axes and be -c, ~b, -a. In the dodecahedron, fig. 15, the right of the two vertical front planes t. meets two axes, the axes a and b, at their extremities, and is parallel to the axis c. Hence the position of this plane is expressed by ic : Ib : la. So, all the planes meet two axes similarly and are parallel to the third. The expression answers as well for the planes i in figs. 13, 14, as for that of the dodecahedron, for the planes have all the same relation to the axes. In the octahedron, fig. 11, the face 1, situated to the right above, like all the rest, meets the axes a, b, c, at their extremities ; so that the expression Ic : Ib : la answers for all. Again, in fig. 17 (p. 20) there are three planes, 2-2, placed symmet- rically on each angle of a cube, and, as has been illustrated, these are the planes of the trapezohedron, fig. 19. The upper one of the planes 2-2 in these figures, when extended to meet the axes (as in fig. 19), intersects the vertical c at its extremity, and the others, a and 6, at twice their lengths from the centre. Hence the expression for the plane is Ic : 2b : 2a. So, as will be found, the left hand plane 2-2 on fig. 17, will have the expression 2c : Ib : 2a; and the right hand one, 2c : 2b : la. Further, the same ratio, by a change of the letters for tho semi-axes, will answer for all the planes of the trapezohedron. In fig. 20 there are other three planes, 2, on each of the angles of a cube, and these are the planes of the trisoctahedron in fig. 21. The lower one of the three on the upper front solid angle, would meet if extended, the extremities of the axes a and 6, while it would meet the vertical axis at twice its length from the centre. The expression 2c : Ib : la indicates, therefore, the position of the plane. So also, Ic : Ib : 2a and Ic: 2b : la represent the positions of the other two planes adjoining ; and corresponding expressions may be similarly 3b- tained for all the planes of the trisoctahedron. Again, in fig. 30, of the cube with two planes on each edge, and in fig. 31, of the tetrahexahsdron bounded by these same planes, the left of the two planes in the front vertical edge of fig. 30 (or the corre- sponding plane on fig. 31) is parallel to the vertical axis ; its intersections with the lateral axes, a and b, are at unequal distances from the centre, expressed by the ratio 2b : la. This ratio for the plane adjoining on the right is Ib : 2a. The position of the former is expressed by the ratio ic : 2b : la, and for the other by ic : Ib : 2a. Thus, for each of the planes of this tetrahexahedron the ratio between two axes is 1 : 2, while the plane is parallel to the third axis. Again, in fig., 22, of the cube with six planes on each solid angle, and in the hexoctahedron in fig. 23, made up of such planes, each of the planes when extended so that it will meet one axis at once its length ISOMETKIO SYSTEM. 23 from the centre, will meet the other axes at distances expressed by a constant ratio, and the expression for the lower right one of the sis; planes will be Be : f b : la. By a little study, the expressions for the other five adjoining planes can be obtained, and so also those for all the 48 planes of the solid. In the isometric system the axes a, 5, c, are equal, so that in the general expressions for the planes these letters may be omitted ; the expressions for the above mentioned forms thus become Cube (fig. 1), a : 1 : i. Tetrahexahedron (fig. 5), i : 1 : 3. Octahedron (fig. 2), 1 : 1 : 1. Trigonal trisoctahedron (fig. 6), Dodecahedron (fig. 3), 1 : 1 : a*. 2:1:1. Trapezohedron (fig. 4), 2 : 1 : 2. Hexoctahedron (fig. 7), 3 : 1 : $. Looking again at fig. 17, representing the cube with planes of the trap- ezohedron, 2 : 1 : 2, it will be perceived that there might be a trap- ezohedron having the ratios H : 1 : 1|, 3:1:3, 4:1:4, 5:1:5, and others; and, in fact, such trapezohedrons occur among crystals. So also, besides the trigonal trisoctahedron 2:1:1 (fig. 21), there might be, and there in fact is, another corresponding to the expression 8:1:1; and still others are possible. And besides the hexoctahedron 3 : 1 : f (fig. 23), there are others having the ratios 4:1:2, 4 : 1 : $, 5 : 1 : f , and so on. In the above ratios, the number for one of the lateral axes is always made a unit, since only a ratio is expressed ; omitting this in the ex- pression, the above general ratios become : for the cube, i : a'; for the octahedron, 1:1; dodecahedron, 1 : i ; trapezohedron, 2:2; tetra- hexahedron, i : 2 ; trigonal-trisoctahedron, 2:1; and hexoctahedron, 3 : f . In the lettering of the figures these ratios are put on the planes, but with the second figure, or that referring to the vertical axis, first. Thus the lettering on the hexoctahedron (fig. 23), is 3-|; on the trigonal trisoctahedron (fig. 21) is 2, the figure 1 being unnecessary ; on the tetrahexahedron (fig. 31), i-2 ; on the trapezohedron (figs. 4 and 19), 2-2; on the dodecahedron (fig. 15), z; on the octahedron, 1; on the cube, a'-i, in place of which II is used, the initial of hexahedron. In the printed page these symbols are written with a hyphen in order to avoid occasional ambiguity, thus 3-f , i-2, 2-2, etc. Similarly, the ratios fcr all planes, whatever they are, may be written. The numbers are usually small, and never decimal fractions. The angle between the planes i-2 (or a" : 1 : 2) and 0, in fig. 30, page 21, may be easily calculated, and the same for any plane of the series i-n (i : 1 : ri). Draw the right-angled triangle, A D C, as in the annexed figure, making the vertical side, C D, twice that of A C, the base ; that is, give them the same ratio as in the axial ratio for the plane. If A'G= 1, CD = 2. Then, by trigonometry, making AG the radius, 1 : R::2 : tan DAC] or 1 : fi::2: cot ADC. Whence tan DAG = cot ADC = 2. By ad- ding to 90, the angle of the triangle obtained by work- ing the equation, we have the inclination of the basal plane 0, or the on the opposite side of the plane a*- 2, (faces of the cube) on the plane i-2. So in all cases, whatever the value of ft, that value equals the tangent of the basal angle of the triangle (or the cotangent of the angle at the vertex), and from this the inclination to the cubic faces is directly ob- 24 CBYSTALLOGBAPHT. tained by adding 90. If n = 1, then the ratio is 1 : 1, as in ACh t and each angle equals 45, giving 135 for the inclination on eithel adjoining cubic face. Again, if the angles of inclination have been obtained by measure- ment, the value of n in any case may be found by reversing the above calculation ; subtracting 90 from the angle, then the tangent of this angle, or the cotangent of its supplement, will equal n, the tangents Varying directly with the value of n. la the case of planes of the m : 1 : 1 series (including 1:1:1, 2:1: 1, etc.), the tangents of the angle between a cubic face in the same zone and theee planes, less 90, varies with the value of m. In the case of the plane 1 (or 1:1:1), the angle between it and the cubic face is 125 16'. Subtracting 90, we have 35 16'. Draw a right-angled triangle, OBC, with 35 16' as its vertex angle. BO has the value of Ic, or the semi-axis of the cube. Make DC=2BC. Then, while the angle OBC has the value of the inclination on the cubic face less 90 for the plane 1:1:1, ODC has the same for the plane 2:1:1. Now, making OC'the radius, and taking it as unity, BG is the tangent of BOG, or cot OBC . SoDC = 2BC is the tan- gent of DOC, or cot ODC. By lengthening the side CD ( 2B C or 2c) it may be made equal to 5BC = 3c, its value in the case of the plane 3:1:1; or to 4BC 4e, its value in the case of the plane 4:1:1; or mBC = me for any plane in the series m : 1 : 1 ; and since in all there will be the same relation between the vertical and the tangent of the angle at the base (or the cotangent of the angle at the vertex), it follows that the tangent varies with the value of m. Hence, knowing the value of the angle in the case of the form 1 (1:1:1), the others are easily calculated from it. BG being a unit, the actual value of 0(7 is | 1/2, or |/jf, it being half the diagonal of a square, the sides of which are 1, and from this value the angle 35 16' might be obtained for the angle OBC. The above law (that for a plane of the m : 1 : 1 series, the tangent of its inclination on a cubic face lying in the same zone, less 90, varies with the value of m, and that it may be calculated for any plane m : 1 : 1 from this inclination in the form 1:1:1), holds also for planes in the series m : 2 : 1, or m : 3 : 1, or any m : n : 1. That is, given the inclination of on 1 : n : 1, its tangent doubled will be Ctat of 2 : n : 1, or trebled, that of 3 : n : 1, and so on; or halved, it will be that of the plane : n : 1 , which expression is essentially the same i& I :2n: 2. These examples show some of the simpler methods of applying iSia- thematics in calculations under the isometric system. The values of the axes are not required in them, because a = b = c 1. 3. Hemihedral Crystals. The forms of crystals described above are called holohedral forms, from the Greek for all and face, the number of planes being all that full symmetry re- quires. The cube has eight similar solid angles similar, that **, in the enclosing planes and plane angles. Consequently the l&vt of full symmetry requires that all should have the same ISOMETRIC SYSTEM. 25 planes and the same number of planes ; and this is the general law for all the forms. This is a consequence of the equality of the axes and their rectangular intersections. But in some crystalline forms there are only half the num- ber of planes which full symmetry requires. In %. 39 a cube ia represented with an octahedral plane on half, that is, four, of 39. the solid angles. A solid angle having such a plane is diag- onally opposite to one without it. The same form is represented in fig. 40, only the cubic faces are the smallest ; and in fig. 41 the simple form is shown which is made up of the four octahe- dral planes. It is a tetrahedron or regular three-sided pyra- mid. If the octahedral faces of fig. 39 had been on the other four of the solid angles of the cube, the tetrahedron made of those planes would have been that of fig. 42 instead of fig. 41. Other hemihedral forms are represented in figs. 43 to 45 j fig. 43 is a hemihedral form of the trapezohedron, fig. 4, p. 7; fig, 44, hemihedral of the hexoctahedron, fig. 7, or a hemi-nex- octahedron. Fig. 45 is a combination of the tetrahedron (plane 1) and hemi-hexoctahedron. Tn these forms figs. 41-44, no face has another parallel to it; ami consequently they are called inclined hemihedrons. Fig. 46 represents a cube with the planes of a tetrahexahe- dron, as already explained. In fig. 47, the cube has only one of the plarves i-2 on each edge, and therefore only twelve in all ; 26 CRYSTALLOGRAPHY. and hence it affords an example of hemihedrism a kind that is presented by many crystals of pyrite. Fig. 48 is the hemihe- 46. dral form resulting when these twelve planes i-2 ave extended to the obliteration of the cubic faces ; and fig. 49 is another, made of the other twelve of these planes. Again, in fig. 50, a cube is represented having only three out of the six planes of fig. 22, and this is another example of hemihedrism. These kinds differ from the inclined hemihedrons in having opposite parallel faces, and hence they are called parallel hemihedrons. 4. Internal Structure of Isometric Crystals, or Cleavage. The crystals of many isometric minerals have cleavage, or *. greater or less capability of division in directions situated symmetrically with reference to the axes. The cleavage direc- tions are parallel either to the faces of the cube, the octahe- dron, or the dodecahedron. In g'alenite (p. 145) there is easy cleavage in three directions parallel to the faces of the cube ; in fluonte (p. 208), in four directions parallel to the faces of the octahedron ; in sphalerite (p. 154), in six directions parallel to the faces of the dodecahedron. These cleavages are an impor- tant means of distinguishing the species. The three cubic cleavages are precisely alike in the ease with which cleavage takes place, and in the kinds of surface obtained ; and so is it with the four in the octahedral directions, and the six in the dodecahedral. Occasionally cleavages of two of these sys- tems occur in the same mineral ; that is, for example, parallel to both the faces of the cube and the octahedron ; but when so, those of one system are much more distinct than those of the other, and cleavage surfaces in the two directions are quite un- like as to smoothness and lustre. 5. Irregularities of Isometric Crystals. A cube has its faces precisely equal, and so it is with each of the form* v : a ; I being the longer lateral and a the Bhortei lateral. In place of the square prism of the dimetric system, i-i, there are the hemiprisms i-i and a-i, or the macropinacoid and brachy- pinacoid, having the expressions ic : ib : Id and ic :_ll : id. The form/ is the rhombic prism, having the expression ic : \6 : \a, corresponding to the square prism / in the dimetric system. The planes i-n or i-n are other rhombic vertical prisms, the former corresponding to ic : nb : \a, the other to ic : \b : ua. If = 2, the plane is lettered either i-2 or t-S. The plane 1*3 has the expression Ic : \b : 3d. m-n and m-n comprise all possible rhombic prisms and octahedrons, and correspond to the expressions me : nb : Id and me : \.b : nu. When m = infinity they become i-fi and i-h, or expressions for vertical rhombic prisms ; when n = infinity they become m-l and m-i, or expressions for macrodomes and brachydomes. The question which of the three axes should be taken as the vertical axis is often decided by reference simply to mathematical convenience. Sometimes the crystals are prominently prismatic only in one direction, as in topaz, and then the axis in this direction is made the vertical. In many cases a cleavage rhombic prism, when there is one, is made the vertical, but exceptions to this are numerous. There is also no general rule for deciding which octahedron should be taken for the unit octahe- dron. But however decided, the axial relations for the planes will re- zuain essentially the same. In fig. 10, had the plune lettered | been made the plane 1, then the series, instead of being as if is in the figure, 1 ij i> &> would have been 2, 1, f, f, in which the mutual axial rela- tions are the same. The relative values of the axes in the trimetric system may be calcu- lated in the same way as that of the vertical axis in the dimetric sys- tem, explained on page 34. The law of the tangents, as stated on page 35, holds for this system. 3. Hemihedral Forms. Hemihedral forms are not common in this system. Some of those so considered have been proved to owe their apparent hemiliedrism to their being of the mono- clinic system, as in the case of datolite and two species of the fchondrodite group. In a few kinds, as, for example, calaimne, one extremity of a crystal differs in its planes from the other. Such forms are termed hemimorphic, from the Greek for half and form. They become polar electric when heated, that is, are pyroelectric, showing that this heraimorpliism is connected with polarity in the crystal. 4. Cleavage. Cleavage may take place in the direction Df either of the diametral planes (that is, either face of the rectan- gular prism) ; but it will be different in facility and in the sur- face afforded for each. In anhydrite, however, the difference is very small. Cleavage may also occur in the direction of the planes of a rhombic prism, either alone or in conr.ection with cleavage in other directions. It also sometimes occurs, as in sulphur, parallel to the faces of a rhombic octal uxlron. 4rO CKYSTALLOGKAPH1. 5. Irregularities in Crystals. The crystals almost never cor- respond in their diametral dimensions with the calculated axial dimensions. They are always lengthened, widened, shortened, or narrowed abnormally, but without affecting the angles. Ex- amples of diversity in this kind of distortion are given in figs. 1 to 7, of barite. 6. Distinctions. In the trimetric system the angle 135 doea not occur, because the three axes are unequal. There are pyra- mids of four similar planes in the system, but never of eight ; and the angles over the terminal edges of the pyramids are never equal as they are in the dimetric system. The rectangu- lar octahedron of the trimetric system is made up of two hori- zontal prisms, as shown in fig. 6, and is therefore not a simple form ; and it differs from the octahedron of the dimetric sys- tem corresponding to it (fig. 16, p. 32) in having the angles over the basal edges of two values. IV. MONOCLINIC SYSTEM. 1. Descriptions of Forms. In this system the three axes are unequal, as in the trimetric system ; but one of the axial inter- sections is oblique, that between the axis a ^vnd the vertical axis c. The following examples of its crystalline forms, figs. 1 to 6, show the effect of this obliquity. On account of it the front or back planes above and below the middle in these figures differ, and the anterior and posterior prismatic planes are une- qually inclined to a basal plane. 2. PYROXENE. HORNBLENDE. The axes and their relations are illustrated in figs. 7 and 8. Fig. 7 represents an oblique rectangular prism, and fig. 8 an oblique rhombic. The former is the diametral prism, like the rectangular of the trimetric system. The axes connect the centre* of the opposite faces, and the planes are of three MONOCLINIO SYSTEM. 41 distinct kinds, being parallel to unlike axes and diametral sec- tions. In the latter, as in the trimetoi:; ihombic prism, the lateral axes connect the centres of the opposite sides. More- over, this rhombic prism may be reduced to the rectangular by the removal of its edges by planes parallel to the lateral axes. 6. MIBABILITB. The axis a, or the inclined lateral axis (inclined at an oblique angle to the vertical axis c), is called the clinodiagonal ; and the axis 6, which is not inclined, the ortJiodiagonaL (from the Greek for right, or rectangular). The vertical section through tho former is called the dinodiagonal section / it is parallel to the plane i-l (fig. 1-6). The vertical section through the latter is iLe orthodiagonal section ' it is parallel to planes i-i. Owing to the oblique angle between a and c, the planes above a differ in their relations to the axes from those below, and hence comes the difference in the angle they make with the basal plane. The halves of a crystal either side of the clinodiagonal section tho vertical section through a and c are alike in all planes and angles. Another important fact is this : that the plane i-l, or that parallel to the clinodiagonal section, is at right angles not only to O and i-i, but to all planes in the zone of O and i-i ' 42 CRYSTALLOGBAPHT. that is, in the clinodiagonal zone ; and this is a consequence of the right angle which axis b makes with both axis c and axis cu The plane i-i is called the orthopinacoid, it being parallel to the orthodiagonal ; and the plane i-l, the clinopinacoid, it being parallel to the clinodiagonal. Vertical rhombic prisms have the same relations to the lateral axes as in the trimetric system. Domes, or horizontal rhombic prisms, occur in the orthodiagonal zone, because the vertical axis c and the orthodiagonal b make right angles with one another. In fig. 6 the planes 1-i, 2-i belong to two such domes. They are called clinodomes, because parallel to the clinodiagonal. In the clinodiagonal zone, on the contrary, the planes above and below the basal plane differ, as already stated, and hence there can be no orthodomes ; they are hemiorthodomes. Thus, in fig. 6, %-i, l-i are planes of hemiorthodomes above i-i, and J-i is a plane of another of different angle below i-i. The plane, and its diagonally opposite, make the hemiorthodome. The octahedral planes above the plane of the lateral axes also differ from those below. Thus, in tigs. 5 and 6, the planes 1, 1 are, in their inclinations, different planes from the planes 1, 1 ; so in all cases. Thus there can be no monoclinic octahedrons only hemioctahedrons. An oblique octahedron is made up of two sets of planes; that is, planes of two hemioctahedrons. Such an octahedron may be modelled and figured, but it will consist of two sets of planes : one set including the two above the basal section in front and their diagonally opposites behind (fig. 9), and the other set including the two below the basal sec- tion and their diagonally opposites (fig. 10). A heiuioctahedron, since it consists of only four planes, ia really an obliquely placed rhombic prism, and very frequently they are so lengthened as to be actual prisms. TRICLINIO SYSTEM. 43 2 Positions of Planes. Lettering of Crystals On account oi the obliquity of the crystals, the planes above and below the basal sec- tion require a distinguishing mark in their lettering, as well as in the mathematical expressions for them. One set is made minus and the other plus. The plus sign is omitted in the lettering. In fig. 7 there are above the basal section (or above i-i) the planes 1-z, -z, 1, |, but bo- low it, $-', 1. T he plus planes are those opposite the acute inter- section of the basal and orthodiagonal sections, and the minus those opposite the obtuse. No signs are needed for planes of the cliuodiago- nal section, since they are alike both above and below the basal sec- tion. The distinction of longer and shorter lateral axis is not available :u this system, since either may be the clinodiagonal. The distinction of clinodiagonal and orthodiagonal planes is indicated by a grave accent over the number or letters referring to the clinodiagonal. The lettering for the cliuodomes on fig. 6 is l-l, 2-1 the i (initial of infinite, with the accent) signifying parallelism to the cfm3y alternately of the two pyramids, putting the shaded planes above directly over those below, he will understand the nature of the hemihedrism. In some hemihedral forms the suppressed planes of the upper pyramid alternate with those of the lower ; but this kind occurs only in the rhombohedral section of the hexagonal system. 4. Cleavage. Cleavage is usually basal, or parallel to a six APATITE. KHOMBOHEDRAL SECTION OF HEXAGONAL SYSTEM 14. sided pyramid. Sometimes there are traces of cleavage parallel to the faces of a six-sided pyramid. 5. Irregularities of Crystal- Distortions sometimes disguise greatly the real forms of hexagonal Crystals by enlarging some planes At the expense of others. This is illustrated in fig. 14, representing the actual form presented by a crystal having the planes shown in fig. 13. Whenever in a prism the prismatic angle is exactly 120 or 150, the form is almost always of the hexagonal system. 2. RHOMBOHEDRAL SECTION. 1. Descriptions of Forms. The following figures, 1 u> 17, represent rhombohedral crystals, and all are of one mineral, cal- cite. They show that the planes of either end of the crystal are in threes, or multiples of threes, and that those above are alternate in position with those below. There is one exception FIGURES OF CRYSTALS OF CALCITE. to this remark, that of the horizontal or basal plane 0, i~ figs. 83 11, 13. The simple rhombohedral forms include: 1. Mhombohedrons, figs. 1 to 6. These forms are included under six equal planes, like the cube, but these planes sire 4 50 CRYSTALLOGRAPHY. rhombic ; and instead of having twelve rectang liar edges, thej have six obtuse edges and six acute. 2. iScalenokedrons, fig. 7. Scaleuohedrons are really double six-sided pyramids ; but the six equal faces of eaoh extremity 14. 15. FIGURES OP CRYSTALS OF CALCITE. of the crystals are scalene triangles, and are arranged in three pairs ; moreover the pairs above alternate with the pairs below ; the edges in which the pairs above and below meet that is the basal edges make a zig-zag around the crystal. 3. Hexagonal prisms, jT, fig. 8. These are regular hexagonal prisms, having angles between their faces of 120. A rhombohedron has two of its solid angles made up of three equal plane angles. When in position the apex of one of these solid angles is directly over that of the other, as in figs. 1 to 6, and also in fig. 18, and the line connecting the apices of these angles (fig. 18) is called the vertical axis. In this position 18. the rhombohedron has six terminal edges, three above and three below, and six lateral edges. As these lateral edges are symmetrically situated around the centre of the crystal, the three lines connecting the centres of opposite basal edges will These lines are tha lateral axes of i-he cross at angles of 60. RUOMB01IKDKAL GECTION OF HEXAGONAL Si STEM. 51 rhombohedron, and they are at right angles to the vertical axis. It is stated on page 45 that rhombohedral forms are, from a mathematical point of view, hemi/iedral under the hexagonal system. The rhombohedron, which may be considered a double three-sided pyramid, is heuiihedral to the double six-sided pyra- mid. Fig. 19, representing the latter foriif}lias its alternate faces shaded ; suppressing the faces shaded the form would le that of fig. 18 ; and suppressing, instead of these, the faces not shaded, the form would be that of another rhombohedron, dif- fering only in position. The two are distinguished as plus and rrdnus rhombohedrons. They are combined in figs. 20, 21, forms of quartz. Khombohedrons vary greatly in the length of the vertical axis with reference to the lateral. Figs. 1, 2, 3, and 18 represent crystals with the vertical axis short, and figs. 4, 5, 6 others with a long vertical axis. In the former the terminal sdges are obtuse and the lateral acute, and the latter have the terminal edges acute and the lateral obtuse ; the former are called obtuse rhombohedrons, and the latter acute. The cube placed on one solid angle, with the diagonal between it and the opposite solid angle vertical, is, in fact, a rhombohe- dron intermediate between obtuse and acute rhombohedrons the edges that are the terminal in this position, and those thai are the lateral, being alike rectangular edges. Fig. 3 has nearlj the form of a cube in this position. The relation of one series of scalenohedrons to the v\\t t r i\to hedron is illustrated in fig. 22. This figure represents a rhombohedron with the lateral edges bevelled. These bevelling planes are those of a scalenohedron, and the outer lines of the same figure show the form of that scalenohedron . which is obtained when the bevelment is continued to the obliteration of the rhombohedral planes. Fig. 14 repre- sents this scalenohedron with the rhombohe- dral planes much reduced in size. Other scalenohedrons result when the terminal edges are bevelled, and still others from pairs of planes on the angles of a rhombohe- dron. The scalenohedron is hemihedral to the tweVe-sided double pyramid (fig. 23). Jn the hexagonal system the three verti- cal axial planes divide the space about the vertical axis into six sectors (fig. 12, p. 48). 62 CRYSTALLOGRAPHY. The twelve-sided double pyramid has in each pyramid a pair of faces for each sector ; that is, six pairs for each pyramid. If now the three alternate of these pairs, and those in the uppei pyramid alternate with those of the lower (the shaded in fig. 23), were enlarged to the obliteration of the rest of the planes, the /Resulting form would be a scalenohedron a solid with three pairs of planes to each pyra- mid instead of six. Such is the mathematical relation of the scalenohedron to the twelve- sided double pyramid. If the faces enlarged were those not shaded in fig. 23, another scalenohedron would be obtained which would be the minus scalenohedron, if the other were designated the plus. Fig. 8 shows the relations of a rhombohe- dron to a hexagonal prism. The planes H replace three of the terminal edges at each base of the prism, and those above alternate with those below. The extension of the planes H to the obliteration of those of the prismatic planes, I, and that of the basal plane O, would produce the rhombohedron cf fig. 1. Figs. 9 and 10 represent the same prism, but with terminations made by the rhombohedron of fig. 2. By comparing the above figures, and noting that the planes of similar forms are lettered alike, the combinations in the figures will be understood. Fig. 1 6 is a combination of the planes of the fundamental rhombohedron jR, with those of an- other rhombohedron 4, and of two scalenohedrons I 3 and I 5 . Fig. 17 contains the planes of the rhombohedron -j-, with those of the scalenohedron I 8 , and those of the prism i. These figures, and figs. 14, 22, have the fundamental rhombohedron revolved 60 from the position in fig. 1, so that two planes H are in view above instead of the one in that figure. 2. Lettering of Figures. Figs. 1 to 6, representing rhomboho- 3rons of the species calcite, are lettered with numerals, excepting fig. 1, la fig. 1 the letter R stands for the numeral 1, and the numerals on Ihtf others represent the relative lengths of their vertical axes, the lateral being equal. In fig. 4 the vertical axis is twice that in fig. 1 ; in fig. 6 thirteen times ; and in fig. 15 the planes lettered 16 are those of a rhom- bohedron whose vertical axis is sixteen times that of fig. 1. The rhom- bohedrons of figs. 1, 5, 6, and 15 are plus rhombohedrons; that is, they are in the same vertical series ; while 2 and 3 are minus rhombohe- drons, as explained above. The rhombohedron, when its vertical axis is reduced in Length to zero, becomes the single basal plane lettered in the series. If, on the contrary, the vertical axis of the rbombohe- ibon is lengthened to infinity, the faces of the rhombohedron become RHOMBOHEDRAL SECTION OF HEXAGONAL SYSTEM. 53 those of a six-sided prism. This last will be seen from the relations of the planes It to Ion fig. 8, and from the approximation to a prismatic form in the planes 16 of fig. 15. For an explanation of the lettering of other planes on rhombohedral crystals, reference must be made to the " Text-Book of Mineralogy." 3. Hemihedrism. Tetartohedrism. Heniihedrism occur* among rhombohedral forms, similar to that in fig. 13, page 48, except that the suppressed planes of one pyramid are alternate with those of the other. One of these is represanted in fig. 24. The planes C-J are six in number at each extremity, and are so situated that they give a spiral aspect to the crystal. If these planes were only three in number at each extremity, the alternate ,hree of the six, the form would be tetarto- hedral to the double six-sided pyramid ; that is, there would be one-fourth the num- ber of planes that exist in the double twelve- sided pyramid, or 6 planes instead of 24. Such cases of hemihedrism and tetartohe- diism are common in crystals of quartz, and when existing, the crystals are said to be plagihedral, from the Greek for oblique and face. In some crystals the spiral turns to the right and in others to the left, and the two kinds are distin- guished as right-handed and left-handed. There are also tetar- tohedral forms in which one whole pyramid of a scalenohedron, or of a rhombohedron, is wanting. For example, in crystals of tourmaline rhombohedral planes, and sometimes scalenohedral, may occur at one extremity of the prism and be absent from the other. This dissimilarity in the two extremities of a crys- tal of tourmaline is connected with pyro-electric polarity in the mineral. Three-sided prisms, hemihedral to the hexagonal prism, are common in some rhombohedral species, as tourmaline. 4. Cleavage. Cleavage usually takes place parallel to the faces of a rhombohedron, as in calcite, corundum. Not uniVe- quently the rhombohedral cleavage is wanting^ and there is highly perfect cleavage parallel to the basal plane, as in graphite, brucite. 5. Irregularities of Crystals. Distortions oc- cur of the same nature with those tinder the other systems. Some examples are given under quartz. Some rhombohedral species, as dolomite, have the opposite faces convex or concave, as in fig. 25. CRYSTALLOGRAPHY. Occasional curved crystals occur, as in fig. 26, representing crystals of quartz, and fig. 2'/ of a crystal of chlorite. The QUARTZ. CHLORITE. feathery crystallizations on windows, called frost, are exampleH of curved forms under this system. VII. DISTINGUISHING CHARACTERS OF THE SEVERAL SYSTEMS OF CRYSTALLIZATION. 1. ISOMETRIC SYSTEM. (1) There may be symmetrical groups of 4 and 8 similar planes about the extremities of each cubic axis ; and of 3 or 6 similar planes about the extremities of each octahedral axis. (2) Simple holohedral forms may consist of 6 (cube), 8 (octahedron), 12 (dodecahedron), 24 (trapezohedron, trigonal trisoctahedron, and tetrahexahedron) , and 48 (hexoc- tahedron) planes. 2. DIMETRIC SYSTEM. (1) Symmetrical groups of 4 and 8 similar planes occur about the extremities of the vertical axis only. (2) Prisms occur parallel only to the vertical axis; and these prisms are either square or eight-sided. (3) The simple holohedral forms may consist of 2 planes (the bases), of 4 planes (square prisms), of 8 planes (eight-sided prisms and aquare octahedrons), of 16 planes (double eight-sided pyra- mids). 3. TRIMETRIC SYSTEM. ( 1 ) Symmetrical groups of 4 similar planes may occur about the extremities of Cither axis, but those of one axis belong equally to the others. (2) The prisms are rhombic prisms only, and these may occur parallel to either axis, the horizontal as well as the vertical. (3) Simple holo TWIN, OE COMPOUND CRYSTALS. 55 hedral forms may consist of 2 planes (the bases, and each pair of diametral planes), of 4 planes (rhombic prisms in the three axial directions), and of 8 planes (the rhombic octahedrons). (4) The forms may be divided into equal halves, symmetrical in planes, along each of the diametral sections. 4. MONOCLINTC SYSTEM. (1) No symmetrical groups of similar planes ever ocour around the extremities of either axis. (2) The prisms are rhombic prisms, and these can occur paral- lel only to the vertical axis and the clinodiagonal. (3) The planes occurring in vertical sections above and below the basal section, either in front or behind, are all unlike in inclination to that section, excepting the prismatic planes in the ortho- diagonal zone ; in other words, true prisms occur in no vertical section excepting the orthodiagonal. (4) Simple forms consist of 2 planes (the bases, the diametral planes, and hemiorthodomes), of 4 planes (rhombic prisms in two directions and hemioctahe- drons). (4) The forms may be divided into equal and similar halves only along the clinodiagonal section. No interfacial angle of 90 occurs except between the planes of the clinodiag- onal zone and the clinopinacoid. 5. TRICLINIO SYSTEM. In triclinic crystals there are no groups of similar planes which include more than 2 planes, and hence the simple forms consist of 2 planes only. The forms are not divisible into halves having symmetrical planes. There are no iuterfacial angles of 90. (5. HEXAGONAL SYSTEM. Symmetrical groups of 3, 6, and 12 similar planes may occur about the extremities of the vertical axis. (2) Prisms occur parallel to the vertical axis, and are either six or twelve-sided (3 in a hemihedral form) and equi- lateral. (3) Simple holohedral forms may consist of 2 planes (the basal), of 6 planes (hexagonal prism), of 12 planes (twelve- sided prisms and double six-sided pyramids), of 24 planes (double twelve-sided pyramids). Simple rhombohedral forina may consist of 2 planes (the basal), of 6 planes (rhombohedrons), and of 12 planes (scalenonedrons) , 2. TWIN, OR COMPOUND CBYSTAIS. Compound crystals consist of two or more single crystals, united usually parallel to an axial or diagonal section. A few are represented in the following figures. Fig. 1 represents a crystal of snow of not uufvequent occurrence. As is evident 56 CRYST ALLOGRAPH Y. to the eye, it consists either of six crystals meeting in a.point, or of three crystals crossing one another ; and besides, there are numerous minute crystals regularly arranged along the rays. Fig. 2 represents a cross (cruciform) crystal of staurolite, vkic k 1. 5. is similarly compound, but made up of two intersecting crys- tals. Fig. 3 is a compound crystal of gypsum, and fig. 4 one of spinel. These will be understood from the following figures. Fig. 5 is a simple crystal of gypsum ; if it be bisected along a b, and the right half be inverted and applied to the other, it will form fig. 3, which is therefore a twin crystal in which one half has a re- verse position from the other. Fig. 6 is a simple octahedron ; if it be bisected along the plane a b c d e, and the upper half, after being revolved half way around, be then united to the lower, it will have the form in fig. 4. Both of these, therefore, are similar twins, in which one of the two component parts is reversed in position. Crystals like figs. 3 and 4 have proceeded from a compound nucleus in which one of the two molecules was reversed ; and those like fig. 1, from a nucleus of three (or six) molecules Compound crystals of the kinds above described, thus differ from simple crystals in having been formed from a nucleuK of two or more united molecules, instead of from a simple nucleus. Compound crystals _tre generally distinguished by their -re-en- tering angles, and often also by the meeting of striae at an angle along a line on a surface of a crystal, the line indicating the plane of junction of the two crystals. Compound crystals are called twolings, threelings, fourlings, according as they consist of two, three, or four united crystals. TWIN, OR COMPOUND CRYSTALS. 57 Fig. 1 represents a threeling, and 2, 3, and 4, twolings. In 3 and 4 the combined crystals are simply in contact along the plane of junction ; in 2 they cross one another; the former are called coidact-twins and the latter penetration-twins. Besides the above, there are also geniculated crystals, as in tlj2 annexed figure of a crystal of rutile. The bending has here *tkeu place at equal distances from the centre of the crystal, and it must therefore have been subsequent in time to the commencement of the crystal. jLhe prism began from a simple molecule ; but after attaining a certain length an abrupt change of direction took place. The angle of geniculation is constant in the same mineral species, for the same reason that the interfacial angles of planes are fixed ; and it is such that a cross section directly through the geniculation is parallel to the posi- tion of a common secondary plane. In the figure given the plane of geniculation is parallel to one of the terminal edges. In rutile the geniculated crystals sometimes repeat the bendings at each end until the extremities meet to form a wheel-like twin. In some species, as albite, the reversion of position on which this kind of twin depends, takes place at so short intervals that the crystal consists of parallel plates, 8. 9. each plate often less than a twen- tieth of an inch in thickness. A sec- tion of such a crystal, made trans- verse to the plate, is given in tig. 8 ; without the twinning the section would have been as in fig. 9. Tiie plates, as the figure shows, make with one another at their edges a re-enter- ing angle (in albite an angle of 172 48'), and hence a plane of the albite crystal at right angles to the twin- ning direction, is covered with a series of ridges and depressions which are so minute as to be only fine striations, sometimes requiring a magnifying power to distinguish. Such striationa in -ilbite are therefore an indication of the compound struc- ture. This kind of twinning is owing to successive changes of polarity in the molecules as the enlargement of the crystal went forward. It occurs in all the tricliiiic feldspars, and is a means of distinguishing them from orthoclase. 58 CRYSTALLOGRAPHY. In some twin crystals the two component parts of the crystal are not united by an even plane, but run into one another with great irregularity. Cases of this kind occur in the species of quartz in twins made up of the forms M and R (or 1). In fig. 10 the shaded parts of the pyramidal planes are of the form 1, and the non-shaded parts of R. Each of the faces is made up partly of R and partly of 1. The limits of the two are easily seen on holding the crystal up to the light, since the 1 portion is less well polished than the other. In this crystal, as in other crys- tals of quartz, the striatioiis of planes * are owing to oscillations between pyram- idal and prismatic planes while the for mation of the latter was in progress. 3. CRYSTALLINE AGGREGATES. The crystalline aggregates here included are the simple, not the mixed ; that is, they are those consisting of crystalline in- dividual? of a single species. The crystalline individuals may be (1) distinct crystals ; (2) fibres or columns ; (3) scales or lamellae ; or (4) grains, either cleavable or not so. 1. Consisting of distinct crystals. The distinct crystal may be either long or short prismatic, stout or slender to acicular (needle-like), and capillary (hair-like) ; or they may have any other forms of crystals. They may be aggregated (a) in lines ; (b) promiscuously with open spaces ; (c) over broad surfaces ; (d) about centres. The various kinds of aggregates thus made ure : a. Filiform. Thread-like lines of crystals, the crystals often not well defined. b. Dendritic. Arborescent slender spreading branches, some- what plant-like, made up of more or less distinct crystals, as in the frost on windows, and in arborescent forms of native cop- per, silver, gold, etc. Fig. 1 1 represents, much magnified an arborescent form of magnetite occurring in mica at Pennsbury, in Pennsylvania. A rborescent delineations over surfaces of rock are Msually called CRYSTALLINE AGGREGATES. 59 it. dtndrites. They have been formed by crystallization from a solution of mineral matter which has entered by some crack and spread between the layers of the rock. They are often black, and consist of oxide of manganese ; others, of a brownish color, are made of limonite ; others, of a red- dish black or black color, of hematite. Moss-like forms also occur, as in moss agate. c. Reticulated. Slender prismatic crystals promiscu- ously crossing, with open spacings. d. Divergent. Free crys- tals radiating from a central point. e. Drusy. A surface is drusy when made up of the extremi- ties of small crystals. 2. Consisting of columnar individuals. a. Columnar, when the columnar individuals are stout. b. Fibrous, when they are slender. c. Parallel fibres, when the fibres are parallel. d. Radiated, when the columns or fibres radiate from centres. e. Stellated, when the radiations from a centre are equal around, so as to make star-like or circularly-radiated groups. f. Globular, when the radiated individuals make globular or hemispherical forms, as in wavellite. y. Botryoidal) when the globular forms are in groups, a lit- tle like a bunch of grapes. The word is from the Greek for a bunch of grapes. k. Mammillary, having a surface made up of low and broad prominences. The term is from the Latin mammilla, a little teat. L Coralloidal, when in open-spaced groupings of slender stems, looking like a delicate coral. A result of successive ad- ditions at the extremity of a prominence, lengthening it into cylinders, the stems generally having a faintly radiated struc- ture. Specimens of all these varieties of columnar structure, except- ing the last, often have a druay surface, the fibres or column! ending in projecting crystals. 60 CRYSTALLOGRAPHY. 3. Consisting of scales or lamellae. a. Plumose, having a divergent arrangement of scales, aa seen on a surface of fracture; e. g., plumose mica. b. Lamellar, tabular ', consisting of flat lamellar crystalline in- dividuals, superimposed and adhering. c. Micaceous, having a thin fissile character, due to the aggi gation of scales of a mineral which, like mica, has eminuai cleavage. d. Septate, consisting of openly-spaced intersecting tabular individuals ; also divided into polygonal portions by reticulat- ing veins or plates. A septarium is a concretion, usually flat- tened spheroidal in shape, the solid interior of which is inter- sected by partitions ; these partitions are the fillings of cracks in the interior that were due to contraction on drying. When the surface of such septate concretions has been worn off, they often have the appearance of a turtle's back, and are sometimes taken for petrified turtles. 4. Consisting of grains. Granular structure. A massive mineral may be coarsely granular or finely granular, as in varieties of marble, granular quartz, etc. It is termed saccha- roidal when evenly granular, like loaf sugar. It may also be cryptocrystalline, that is, having no distinct grains that can. be detected by the unaided eye, as in flint. The term crypto- crystalline is from the Greek for concealed crystalline. Aphani- tic, from the Greek for invisible, has the same signification. The term ceroid is applied when this texture is connected with a waxy lustre, as in some common opal. Under this section occur also globular, botryoidal, and inam- millary forms, as a result of concretionary action in which no distinct columnar interior structure is produced. They are called pisolitic when in masses consisting of grains as large as peas (from the Latin pisum, a pea), and oolitic when the grains are not larger than the roe of a fish, from the Greek for egg. 5. Forms depending on mode of deposition. Besides the above, there are the following varieties which have ccme from mode of deposition : a. Stalactitic, having the form of a cylinder, or cone, haLg- ing from the roofs of cavities or caves. The term stalactite is usually restricted to the cylinders of carbonate of calci im hanging from the roofs of caverns ; but other minerals are said to have a stalactitic form when resembling these in their general shape and origin. Chalcedony and brown iron ore are often stalacti- tic. Interiorly the structure may be either granular, radiatelj fibvo'ls, or concentric. CRYSTALLINE AGGREGATES. 61 6, Concentric. When consisting of lamellae, lapping one ovei another around a centre, a result of successive concretion- ary aggregations, as in many concretionary forms, most pisolite, part of oolite, some stalactites, etc. c. Stratified, consisting of layers, as a result of deposition : e. g ; sc me travertine, or tufa. d. Jiznded / color-stratified. Like stratified in origin, but the layers usually indicated only by variations in color ; the band- ing is shown in a transverse section : e. g., agate, much stalag- mite, riband jasper. e. Geodes. When a cavity has been lined by the deposition of mineral matter, but not wholly filled, the enclosing mineral is called a geode. The mineral is often banded, owing to the successive depositions of the material, and frequently has its inner surface set with crystals. Agates are often slices or frag- ments of geodes. 6. Forms derived from the crystals of other minerals. Pseu- domorphs. Crystalline aggregates, especially the granular, sometimes have forms derived from the crystals of other minerals either (1) Because a result of cotemporaneous removal and substi* tution ; or (2) Because a result of the alteration of such crystals ; or (3) Because filling spac.es that had been left unoccupied in consequence of previous removal. For example. Crystals occur having the forms of calcite (calcium carbonate, or " carbonate of lime "), but consisting of quartz or silica. They were made from calcite crystals by the action of some solution containing silica, the solution dissolving away the calcite and depositing at the same time silica or quartz. Specimens occur showing all stages in the change from the ear- liest in which the calcite is thinly coated with quartz, to the last, in which it is all quartz. Such crystals are pseudoinorphs of quartz after calcite. Siliceous fossil shells and corals are similar pseudomorphs after catcite, since shells and corals con- sist chiefly of calcite. Other quartz pseudomorphs have the form of fluorite, barite, etc. Again, the forms of calcite occur with the constitution of limonite, a hydrous iron oxide. In such a case the iron oxide was in the solution that corroded and dissolved away the calcite. Again, the forms of calcite occur with the constitution of serpentine, a hydrous magnesium silicate ; and in this ctiso the ingredients of the serpentine silicate were present when the 62 CRYSTALLOGRAPHY. calcite was dissolved away by the corrosive solvent, and took its place as the calcite particles were removed. In all the above cases the pseudomorphs were made by simple removal and cotemporaneous substitution. Again, crystals of the form of chrysolite, a magnesium sili ca^.e, occur, altered to serpentine, a hydrous magnesium silicate. II 3re the pseudomorph was made by a process of alteration, part of the ingredients remaining, and only water added. Again, crystals of siderite (spathic iron or iron carbonate) occur changed to limoriite, a hydrous iron oxide. Here there was an oxidation of the iron of the carbonate, and the addition of water. This is another example of pseudomorphs by altera- tion. Similarly orthoclase changes to kaolin, and kaolin has the form at times of orthoclase crystals. Again, crystals of the form of those of common salt occur consisting of clay or of calcite, which were made by deposition in a cavity left by the dissolving away of an imbedded crystal of salt. These are pseudomorphs by deposition. Again, crystals of aragonite, prismatic calcium carbonate, occur consisting of calcite or rhombohedral calcium carbon- ate ; and here there is a change in crystallization without any change of chemical composition. 7. Fracture. Kinds of fracture in these crystalline aggre- gates depend on the size and form of the particles, their cohe- sion, and to some extent their having cleavage or not. Among granular varieties, the influence of cleavage is in all cases very small, and in the finest almost or quite nothing. The term hackly is used for the surface of fracture of a metal, when the grains are coarse, hard, and' cleavable, so as to be sharp and jagged to the touch ; even, for any surface of fracture when it is nearly or quite flat, or not at all conchoidal ; conchoidal, when the mineral, owing to its extremely fine or cryptocrystal- line texture and hardness, breaks with shallow concavities and convexities over the surface, as in the case of flint. The word conchoidal is from the Latin concha, a shell. These kinds of fracture are not of much importance in mineralogy, siuce they distinguish varieties of minerals only, and not species. HAKDNESS TENACITY SPECIFIC GRAVITY. 03 2. PHYSICAL PROPERTIES OF MINERALS. THE physical properties referred co in the description and determination of minerals are here treated under the following heads: (1) Hardness; (2) Tenacity; (3) Specific Gravity; (4) Refraction, Polarization ; (5) Diaphaneity, Color, Lustre; (6) Electricity and Magnetism ; (7) Taste and Odor, 1. HARDNE&S. The comparative hardness of minerals is easily ascertained, and should be the first character attended to by the student in examining a specimen. It is only necessary to draw a lile across the specimen, or to make trials of scratching one wi.th another. As standards of comparison the following minerals have been selected, increasing gradually in hardness from talc, which is very soft and easily cut with a knife, to the diamond. This table, called the scale of hardness, is as follows : 1, talc, common foliated variety; 2, rock salt j 3, calcfc t transparent variety ; 4, Jluorite, crystallized variety; 5, apatite, transparent crystal ; 6, ort/ioclase, cleavable variety ; 7, quartz, transparent variety ; 8, topaz, transparent crystal ; 9, sapphire^ cleavable variety; 10, diamond. If, on drawing a file across a mineral, it is impressed as easily as Jluorite, the hardness is said to be 4 ; if as easily as ortho- close, the hardness is said to be 6 ; if more easily than ortho- clase, but with more difficulty than apatite, its hardness is de- scribed as 5J or 5 '5. The file should be run across the mineral three or four times, and care should be taken to make the trial on angles equally blunt, and on parts of the specimen not altered by exposure. Trials should also be made by scratching the specimen under examination with the minerals in the above scale, since some- times, owing to a loose aggregation of particles, the file wears tlown the specimen rapidly, although the particles are very haru. In crystals the hardness is sometimes appreciably different in degree in the direction of different axes. In crystals of mic* 64 PHYSICAL PROPERTIES OF MINERALS the hardness is less on the basal plane of the prism, that is, on the cleavage surface, than it is on the sides of the prism. On the contrary, the terminatitn of a crystal of cyanite is harder than the lateral planes The degree of hardness in different directions may be obtained with great accuracy by means of an instrument called a sclerometer. 2. TENACITY. The following rather indefinite terms are used with reference to the qualities of tenacity, malleability, and flexibility in min- erals : 1. ^Brittle. When a mineral breaks easily, or when parts of the mineral separate in powder on attempting to cut it. 2. Malleable. When slices may be cut off, and these slices will flatten out under the hammer, as in native gold, silver, copper. 3. Sectile. When thin slices maybe cut off with a knife. All malleable minerals are sectile. Argentite and cerargyrite are examples of sectile ores of silver. The former cuts nearly like lead and the latter nearly like wax, which it resembles. Minerals are imperfectly sectile when the pieces cut off pul- verize easily under a hammer, or barely hold together, as sele- nite. 4. Flexible. When the mineral will bend, and remain bent after the bending force is removed. Example, talc. 5. Elastic. When, after being bent, it will spring back to its original position. Example, mica. A liquid is said to be viscous when on pouring it the drops lengthen and appear ropy. Example, petroleum. 3. SPECIFIC GRAVITY. The specific gravity of a mineral is its weight compared with that of some substance taken as a standard. For solids ar.d liquids distilled water, at 60 F., is the standard ordinarily used ; and if a mineral weighs twice as much as water, its spe- cific gravity is "2 ; if three times it is three. It is then necessary to compare the weight of the mineral with the weight of an equal bulk of water. The process is as follows : First weigh a fragment of the mineral in the ordinary way, SPECIFIC GRAVITY. 65 with a delicate balance j next suspend the mineral by a hair, or fibre of silk, or a fine platinum wire, to one of the scales, im- merse it thus suspended in a glass of distilled water (keeping the scales clear of the water) and weigh it again; subtract the second weight from the first, to ascertain the loss by immersion, and divide the first by the difference obtained ; the result is the specific gravity. The loss by immersion is equal to the weight of an equal volume of water. The trial should be made on a small fragment ; two to five grains are best. The specimen should be free from impurities and from pores or air-bubbles. For exact results the temperature of the water should be noted, and an allowance be made for any variation from the height of thirty iuches in the barometer. The observation is usually made with the water at a temperature of 60 F. ; 39 '5 F., the temperature of the maximum density of water, is preferable. The accompanying figure represents the spiral balance of Jolly, by which the weight is measured by the torsion of a spiral brass wire. On the side of the upright (A) which faces the spiral wire, there is a graduated mirror, and the readings which give the weight of the mineral in and out of water are made by means of an index (at m) connected with the spiral wire ; and its exact height, with reference to the graduation, is obtained by noting the coincidence between it and i:s image as reflected by the graduated mir- ror, c and d are the pans in which the piece of mineral is placed, first in c, the one out of the water, and then in d, that in the water. Another process, and one available for vorous as well as compact minerals, is per- .ormed with a light glass bottle, capable of holding exactly a thousand grains (or any known weight) of distilled water. The specimen should be reduced to a coarse pow- der, Pour out a few drops of water from the bottle and weigh it ; then add the pow- dered mineral till the water is again to the brim, and reweigh it ; the difference in the two weights, divided by the loss oi water poured out, is the specific gravity sought. The weight of the glass bottle itself is here supposed to be balanced by an squivalent weight in the other scale. 5 771 66 PHYSICAL PROPERTIES OF MINERALS. 4. REFRACTION AND POLARIZATION. Minerals differ widely in their refracting and polarizing properties, and hence these properties are a convenient means of distinguishing species. The explanations of the subject, and the methods of careful experimenting, will be found in treatises on optics, and also at considerable length, and with minute directions as to the use of instruments, in the Text-Book of Mineralogy. Only a few of the simpler facts required for the ordinary purposes of the mineralogist are here mentioned. The character of the refraction varies according to the sys- tem of crystallization. A. In isometric crystals there is simple refraction alike in all directions, and no polarization. B= In dimetric and hexagonal crystals the vertical axis, or axis of symmetry, is the direction of the optic axis ; in all directions except this a transmitted ray of light is doubly re- fracted. Such crystals are optically uniaxial. C. In trimetric, monoclinic, and triclinic crystals, which have the three axes unequal, there are two directions of no double-refraction. Such crystals are optically biaxial. 1. Isometric System. In the isometric system there is no reference whatever in the refraction to crystalline structure, and in this respect substances thus crystallizing are like water. There is only simple refraction. The index of refraction is ob- tained by dividing the sine of the angle of incidence of a ray of light by the sine of its angle of refraction. Thus if a ray of light strike the surface of a transparent plate of the mineral at an angle of 40 from the perpendicular, and then passes through the plate at an angle of 30 from the perpendicular, owing to the refraction, the sine of 40 divided by the sine of 30 will be the index of refraction. Now the index of refraction of air being made the unit, that of water is 1 '335 ; of fluorite, 1'434 ; of rock salt, 1-557; of spinel, 1*764; of garnet, 1-815; of blende, 2-260; of diamond, 2'439. 2. Crystals Uniaxial in Polarization. A transparent cleav- age plate from a crystal of calcite shows what is called double refraction. Placed over a line drawn on any surface, two parallel lines are seen, one produced by the ordinary ray, and the other by the extraordinary ray. Both rays are polarized, and in planes at right angles to each other. Prisms, called Nicol prisms, made from transparent calcite (Iceland Spar), are employed for obtaining polarized light. Transparent REFRACTION AND POLARIZATION. 67 plates of tourmaline, cut from a crystal parallel to the vertical axis, also are used for this purpose. Another method of ob- taining it is by reflection light, when reflected at a certain angle from a polished surface, being polarized ; the angle of reflection differs for different substances. The above figure represents a simple polariscope made with two tourmaline plates, which is convenient for many ordinary observations. The best instruments for the purpose are made with Nicol prisms, and are adapted to microscopic work. The prisms, placed within the tube of the instrument, one of them below the stage, are arranged so as to admit of revolution ; and the stage also has a graduated circle and revolves. The com- pound microscope also is often converted into a polariscope by Nicol prisms arranged for this purpose. When a crystal with one axis of polarization, as, for example, calcite, is examined by means of a ray of polarized light passed in the direction of the vertical axis, concentric circular rings are seen, having the colors of the spectrum intersected by either a black or a white cross, as in figs. 1, 2. To make the observa- 3. tion it is necessary that the calcite crystal should have its ex- tremities polished at right angles to the vertical axis. If a tourmaline plate be placed against or near one of its polished 68 PHYSICAL PROPERTIES OF MINERALS. faces, and a similar tourmaline plate in front of the opposite face, the colored rings will be seen on looking through ; and by revolving one of the tourmaline plates a change will be observed at each 90 of revolution, in the colors of the rings, and in the variations in appearance of the cross from black to white, and the reverse. The fact in any case that the rings of color are perfect circles, and the black cross a symmetrical one, is proof that the crystal is either of the dimetric or hexagonal system. But sometimes very exact observation is necessary to deter- mine the truth. 3. Crystals Biaxial in Polarization. Biaxial crystals are those having two optic axes, and the angle between them is called the axial angle. When a section of such a crystal, at right angles to the line bisecting the acute axial angle, is viewed in converging polar- ized light, the two axes are seen with a series of elliptical col- ored rings surrounding each. If the section is so placed that the line joining the axes coincides with the vibration-plane of either Nicol prism, or tourmaline plate, an unsymmetrical 0. GLAUBER SALT. PHLOGOPITE, ANTWERP, N. Y. black cross is also seen, as in fig. 4; if it makes an angle of 45 with this, two curved black bars are observed, as in fig. 5. In either case the colors are reversed, and the black changed to white as one of the Nicols is revolved. Fig. 6 shows the axial figure for phlogopite (in the second position mentioned above) where the axial angle is very small. The rings are loss numerous and farther apart the thinner the section that is employed in making the observations. In muscovite (common mica) the angle between the axes is 50 to 70, and, if the tourmaline tongs are employed, the two REFRACTION AND POLARIZATION. C9 series of rings are visible only when viewed in directions very oblique to one another. 4. Circular Polarization in Uniaxial Crystals. It is stated on page 53 that quartz crystals have often a left handed and a right-handed arrangement of planes. This is connected with a right-handed and left-handed molecular structure in crystals of this species. When a plate cut at right angles to the axis is ex- amined by the polarized light, instead of presenting a black cross, the centre of the rings appears brightly colored, and if the polarizer is revolved, this color changes from blue to yellow, thnn red, right-handed crystals requiring revolution to the right and left-handed to the left for this succession. This prop- erty seems to distinguish the smallest grains of quartz, and may be easily observed in a good polariscope. 5. Anomalies in Polarization. There are some isometric crystals which have the property of polarization. Boracite is one example ; and it is explained by the presence of another mineral in minute particles, distributed regularly through the crystals. Perofskite is another case ; and it has suggested a doubt as to its being isometric. Octahedrons of alum some- times have polarization, and it has been shown to be due to the crystals being made up of thin plates light, when transmitted through a pile of such plates, becoming polarized. Dia- monds are sometimes vmiaxial. Aualcite was long since described by Sir David Brewster as an example of polarization under the isometric system. Its trapezohedrons exhibit a symmetrical arrangement of lines of prismatic colors and alternating dark lines with cross-bands, as imperfectly shown in the annexed figure. Trapezohedrons of leucite are somewhat similar in their polarizing character. The effect in both species is connected with twinning ; but, besides, accord- ing to recent observers, the crystallization is dimelric. One writer makes crystals of analcite to be trimetric twins, analogous those of phillipsite. Twinning in crystals is a very common source of irregularities. A regular twinning of laminae of bi- axial crystals around a centre may give a uniaxial character to the twin. Apophyllite is a dimetric species, showing peculiari- ties in its colors arising from the different action of the mineral in light of different colors. 70 PHYSICAL PROPERTIES OF MENEBAL8. 5. DIAPHANEITY, LUSTRE, COLOR. 1. DIAPHANEITY. Diaphaneity is the property which many objects possess of transmitting light ; or, in other words, of permitting more or less light to pass through them. This property is often called transparency, but transparency is properly one of the degrees cf diaphaneity. The following terms are used to express the different degrees of this property : Transparent a mineral is said to be transparent when the outlines of objects, viewed through it, are distinct. Example, glass, crystals of quartz. Subtransparent; or semitransparent when objects are seen but their outlines are indistinct. Translucent when light is transmitted, but objects are not seen. Loaf sugar is a good example j also Carrara marble. Subtranslucent when merely the edges transmit light faintly. When no light is transmitted the mineral is described as opaque. 2. LUSTRE. The lustre of minerals depends on the nature of their surfaces, which causes more or less light to be reflected. There are dif- ferent degrees of intensity of lustre, and also different kinds of lustre. a. The kinds of lustre are six, and are named from some familiar object or class of objects. 1. Metallic the usual lustre of metals. Imperfect metallic lustre is expressed by the term submetallic. 2. Vitreous the lustre of broken glass. An imperfect vitreous lustre is termed subvitreous. Both the vitreous and sub vitreous lustres are common. Quartz possesses the former in an eminent degree ; calcareous spar often the latter. This kind of lustre may be exhibited by minerals of any color. 3. Hesinous lustre of the yellow resins. Example, some opal, zinc blende. 4. Pearly like pearl. Example, talc, native magnesia, gtil- bite, etc. When united with submetallic lustre the term metallic-pearly is applied. ii. 8Uky like silk; it is the result of a. fibrous structure. DIAPHANEITY LU8TKE COLOK. 71 Example, fibrous calcite, fibrous gypsum, and many fibrous minerals, more especially those which in other forms have a pearly luwtre. 6. Adamantine the lustre of the diamond. When sub- metallic, it is termed metallic adamantine. Example, some varieties of white lead ore or cerussite. b. The degrees of intensity are denominated as follows: 1. Splendent when the surface reflects light with great bril- liancy and gives well-defined images. Example, Elba hematite, tin ore, some specimens of quartz and pyrite. 2. Shining when an image is produced, but not a well-de- fined image. Example, calcite, celestite. 3. Glistening when there is a general reflection from the surface, but no image. Example, talc. 4. Glimmering when the reflection is very imperfect, and apparently from points scattered over the surface. Example, flint, chalcedony. A mineral is said to be dull when there is a total absence of lustre. Example, chalk. 3. COLOR. 1. Kinds of Color. In distinguishing minerals, both the ex ternal color and the color of a surface that has been rubbed 01 scratched, are observed. The latter is called the 'streak, and the powder abraded, the streak-powder. The colors are either metallic or unmetallic. The metallic a^ named after some familiar metal, as copper- red, bronze-yeilow, brass-yellow, gold-yellow, steel-gray, lead- gray, iron-gray. The unmetallic colors used in characterizing minerals are various shades of white, gray, black, blue, green, yellow, red and brown. There are thus snow-white, reddish-white, greenish-white, milk-white, yellowish-white. Bluish-gray, smoke-gray, greenish-gray, pearl-gray, ash-gray. Velvet-black, greenish-black, bluish-black, grayish-black. Azure-blue, violet-blue, sky-blue, indigo-blue. Emerald-green, olive-green, oil-green, grass-green, apple-green, bUckish-green, pistachio-green (yellowish). Sulphur-yellow, straw-yellow, wax-yellow, ochre-yellow, honey-yellow, orange-yellow. Scarlet-red, blood-red, flesh red, brick-red, hyaiinth-red, rose- red, cherry-red. 72 PHYSICAL PROPERTIES OF MINERALS. Hair-brown, reddish-brown, chestnut-brown, yellowish-brown, pinchbeck-brown, wood-brown. A play of colors this expression is used when several pris- maiic colors appear in rapid succession on turning the mineral. The diamond is a striking example ; also precious opal. Change of colors when the colors change slowly on turning in different positions, as in labradorite. Opalescence when there is a milky or penrly reflection from the interior of a specimen, as in some opals, and in cat's eye. Iridescence when prismatic colors are seen within a crystal, it is the effect of fracture, and is common in quartz. Tarnish when the surface colors differ from the interior ; it is the result of exposure. The tarnish is described as irised when it has the hues of the rainbow. 2. Dichroism, Trichroism. Some crystals, under each of the systems excepting the isometric, have the property of present- ing different colors by transmitted light in different directions. The property is called dichroism when these colors are seen in two directions, and trichroism (or pleochroism) if seen in three directions. The colors are always the same in the direction of equal axes and often unlike in the direction of- unequal axes. As dimetric and hexagonal crystals have the lateral axes equal they can present different colors only in two directions, the vertical and lateral; while all crystals that are optically biaxial may be trichroic. The mineral iolite is a noted example, and received the name dichroite on account of this property. Transparent colored crystals of tourmaline, topaz, epidote, mica, diaspore, and many other species exhibit it. Tourmaline crystals, when transpar- ent or translucent transverse to the prism, are opaque in the direction of the vertical axis ; and so also are thick crystals of mica. Colored varieties of hornblende are dichroic, while those of the related mineral, pyroxene, are not so. This quality is best observed by means of polarized light. On examining a mineral with a tourmaline plate, or Nicol prism, the two colors in a dichroic mineral are successively seen as the tourmaline or Nicol is revolved ; and if there is no dichroism there is no change of color. A small instrument, containing a prism of calcite, has been constructed for showing the dichro- ism, called the dichroscope. On looking through it at a di- chroic crystal, the aperture against the crystal appears double, owing to the double refraction of the calcite, one image being made by the ordinary ray and the other by the extraordinary ELECTBICITY AND MAGNETISM. 73 ray ; and the two colors are seen side by side, at intervals of 90 in the revolution of the mineral. For opaque minerals it is necessary to make a thin transparent section of the mineral and examine it with a polari scope, or with a microscope arrange^ ''. ict as one by the addition of one Nicol prism. The opaque /-nblende of rocks is thus distinguished from pyroxene, and so in other cases. 3. Asterism. Some crystals, especially the hexagonal, when viewed in the direction of the vertical axis, present peculiar re- flections in six radial directions. This arises either 'from pecu- liarities of texture along the axial portions, or from some im- purities. A remarkable example of it is that of the asteriated sapphire, and the quality adds much to its value as a gem. The six rays are sometimes alternately shorter, indicating the rhombohedral character of the crystal. 4. Phosphorescence. Several minerals give out light either by friction or when gently heated. This property of emitting light is called phosphorescence. Two pieces of white sugar struck against one another give a feeble light, which may be seen in a dark place. The same effect is obtained on striking together fragments of quartz, and even the passing of a feather rapidly over some specimens o r zinc blende is sufficient to elicit light. Fluorite is the most convenient mineral for showing phos phorescence by heat. On powdering it, and throwing it on a plate of metal heated nearly to redness, the whole takes on a bright glow. In some varieties the light is emerald green ; in others, purple, rose, or orange. A massive fluor, from Hun tington, Connecticut, shows beautifully the emerald green phos- phorescence. Some kinds of white marble, treated in the same way, gU ^ out a bright yellow light. After being heated for a while the mineral loses its phoa- phorescence ; but a few electric shocks will, in many cases, to some degree restore it again. 6. ELECTRICITY, AND MAGNETISM. ELECTRICITY. Many minerals become electrified on being nibbed, so that they will attract cotton and other light sub- stances ; and when electrified some exhibit positive and others negative electricity, when brought near a delicately suspended magnetic needle. The diamond, whether polished or not, ai- 74 PHYSICAL PROPERTIES OF MINERALS. ways exhibits positive electricity, while other gems become negatively electric in the rough state, and positively only in the polished state. Some minerals, thus electrified, retain the powoi of electric attraction for many hours, as topaz, while others lose it in a few minutes. Many minerals become electric when heated, and such speciea are said to be pyro~electric, from the Greek put, fire, and electric. A prism of tourmaline, on being heated, becomes polar ; ono extremity will be attracted, the other repelled, by a pole of a strong magnet. The prisms of tourmaline have different second- ary planes at the two extremities. Several other minerals have this peculiar electric property, especially boracite and topaz, which, like tourmaline, are hemi- hedral in their modifications. Boracite crystallizes in cubes, with only the alternate solid angles similarly replaced (figs. 39, 40, page 25). Each solid angle, on heating the crystals, be- comes an electric pole ; the angles diagonally opposite are dif- ferently modified and have opposite polarity. Pyroelectricity has been observed also in crystals that are not hemihedral, and in many mineral species. In some cases the number of poles is more than two. In prelmite crystals a large series occur dis- tributed over the surface. MAGNETISM. The name Lodestone is given to those specimens of an ore of iron, called magnetite which have the power of at- traction like a magnet ; it is common in many beds of magnetite. When mounted like a horse-shoe magnet, a good lodestone will lift a weight of many pounds. This is the only mineral that has decided magnetic attraction. But several ores containing iron are attracted by the magnet, or, when brought near a magnetic needle, will cause it to vibrate; and moreover, the metals nickel, cobalt, manganese, palladium, platinum and os- mium, have been found to be slightly magnetic. Many minerals become attractable by the magnet after being heated that are not so before heating. This arises from a change of part or all of the iron to the magnetic oxide. 7. TASTE AND ODOR. Taste belongs only to the soluble minerals ; the kinds are 1. Astringent the taste of vitriol. 2. Sweetish-astringent the taste of alum. 3. Saline taste of common salt. TASTE AND ODOB. 75 4. Alkaline taste of soda. 5. Cooling taste of saltpetre. 6. Bitter taste of epsom salts. 7. Sour taste of sulphuric acid. Odor is not given off by minerals in the ry, unchanged state, except in the case of a few gases and soluble minerals. By friction, moistening with the breath, the action of acids and the blowpipe, odors are sometimes obtained, which are thus designated : 1. Alliaceous the odor of garlic. It is the odor of burning arsenic, and is obtained by friction, and more distinctly by means of the blowpipe, from several arsenical ores. 2. Horse-radish odor the odor of decaying horse-radish. It is the odor of burning selenium, and is strongly perceived when ores of this metal are heated before the blowpipe. 3. Sulphureous odor of burning sulphur. Friction will elicit this odor from pyrites, and heat from many sulphides. 4. Fetid the odor of rotten eggs or sulphuretted hydrogen. It is elicited by friction from some varieties of quartz and lime- stone. 5. Argillaceous the odor of moistened clay. It is giren oflf by serpentine and some allied minerals when breathed upon. Othf r?, as pyrargillite, afford it when heated. 70 CHEMICAL PROPERTIES OF MINERALS. 8. CHEMICAL PROPERTIES MINERALS. OP THE chemical properties of minerals are of two kinds. (1) Those of the chemical composition of minerals, (2) those de- pending on their chemical reactions, with or without fluxes, in- cluding results obtained by means of the blowpipe. 1. CHEMICAL COMPOSITION. All the elements made known by chemistry are found in minerals, for the mineral kingdom is the source of whatever living beings plants and animals contain or use. A list of these elements, as at present made out, is contained in the fol- lowing table, together with the symbol for each used in stating the composition of substances. These symbols are abbreviations of the Latin names for the elements. A few of these Latin names differ much from the English, as follows : Stibium Sb = Antimony Cuprum Cu = Copper Ferrum Fe =r Iron Plumbum Pb =z Lead Hydrargyrum Hg = Mercury Kalium Argentum Natrium Stannura K = Potassium Ag = Silver Na = Sodium Sn = Tin Wolframium W = Tungsten TABLE OF THE ELEMENTS. Aluminum Antimony Arsenic Barium Bismuth Boron Bromine Cadmium Ceesium Calcium Carbon Cerium Chlorine Chromium Cobalt Al 27-4 Sb 120 As 75 Ba 137 Bi 210 B 11 Br 80 Cd 112 Cs 133 Ca 40 C 12 Ce 138 Cl 35-5 Cr 522 Co 58-8 Columbium (Niobium) Cb (Nb) 94 Copper Cu 63 '4 Didymium D 144 '8 Erbium E 168 -9 Fluorine F 19 Gallium Ga 68 ? Glucinum (Beryllium) G (Be) 9 '4 Gold Au 197 Hydrogen H 1 Indium In 113 '4 Iodine I 127 Jridium Ir 198 Iron Fe 56 Lanthanum La 139 Lead Pb 207 CHEMICAL COMPOSITION OF MINERALS. 77 Li 7 Silver Mg 24 Silicon Mn 55 Sodium Kg 200 Strontium Mo 96 Sulphur Ni 58-8 Tantalum H 14 Tellurium Oa 199-2 Thallium 16 Thorium Pd 106-6 Tin P 31 Titanium Pt 197-6 Tungsten K 39-1 Uranium Ro 104-4 Vanadium Rb 85-4 Yttrium Ru 104-4 Zinc 8e 79 '4 ' Zirconium Aff Si 108 28 Na 23 Sr 87'fl S 32 Ta 182 Te 128 Tl 204 Th 235 Sn 118 Ti 50 W 184 U 240 V 51-2 Y 92 Zn 65-2 Zr 89-6 Lithium Magnesium Manganese Mercury Molybdenum Nickel Nitrogen Osmium Oxygen Palladium Phosphorus Platinum Potassium Rhodium Rubidium Ruthenium Selenium The combining weights indicate the proportions in which the elements combine. Thus, assuming hydrogen, the lightest of the elements, to be 1, or the unit of the series, the combining weight of oxygen is 16 ; of iron, 6 ; of magnesium, 24; of Biilphur, 32; and so on. When hydrogen and oxygen combine it is in the ratio of 2 pounds of hydrogen, or else 1 pound of hydrogen, to 16 pounds of oxygen, and two different compounds thus result. When oxygen and magnesium combine it is in the ratio of 16 pounds of oxygen to 24 of magnesium. Oxygen and iron combine in the ratio of 16 of oxygen to 56 of iron ; or of 24 of oxygen (1 times 16) to 56. Sulphur and oxygen combine in the ratio of 32 of oxygen to 32 of sulphur; or of 48 to 32 of sulphur. The combining weights are often called the atomic weights. The following is the manner of using the symbols : For the compound consisting of hydrogen and oxygen in the ratio of 2 to 16, the chemical symJJ&l is H.,O, meaning 2 of hydrogen to 1 of oxygen. (This compound is water.) For the compound of oxygen and magnesium just referred to, the symbol is MgO; for the two compounds of oxygen and iron, FeO, protoxide of iron ; Fe.,O 3 , sesquioxide of iron, the ratio of 1 to 1^ being ex- pressed by 2 to 3 ; for the two compounds of sulphur and oxy- gen, SO a and SO 3 . Some of the elements so closely resemble one another that their similar compounds are closely alike in crystallization and other qualities, and they are therefore said to be isomorphous. This is true of iron, magnesium, calcium, and two or three other related elements. In one group of compounds of these bases, the carbonates, the crystalline form for each is rhombohe- 78 CHEMICAL PROPERTIES OF MINERALS. dral, and among them there is a difference of less than two d&. grees in the angle of the rhouibohedron. Besides a carbonate of calcium, a carbonate of magnesium, and a carbonate of iron, there is also a carbonate of calcium and magnesium* in which half of the calcium of the first of these carbonates is replaced by half an atom of magnesium ; and another species in which the base, instead of being all magnesium, is half magnesium and half iron. By half is here meant half in the proportion of their combining weights. The replacement of one of these elements by the other, and similar replacements among other groups of related elements, run through the whole range of mineral compounds. Thus we have sodium replacing potassium, arsenic replacing phosphorus and antimony ', and so on. In the combinations of oxygen and iron, as illustrated above, oxygen is combined with the iron in different proportions. FeO contains 1 of Fe (iron) to 1 of O (oxygen) and Fe^, or, as it is often written, FeO 3 , contains Fe to 1 of O. As the iron in each of these cases satisfies the oxygen, it is evident that the iron must be in two different states, (1) a protoxide state, and (2) a sesquioxide state. One part of iron in this sesquioxide state ( = f Fe) often replaces in compounds one part of iron in the protoxide state (or IFe), with no greater change of quali- ties than happens in the replacement of iron by magnesium, or calcium, explained above ; or, avoiding fractions, 3 parts of Fe in the protoxide state replaces 2Fe in the sesquioxide state. Writing e for the last 2Fe, the statement becomes 1 of Fe 3 replaces 1 of Fe. Aluminium occurs only in the sesqui- oxide state, and the ordinary symbol of the oxide is A1 4 O 8 , or AlO 3 . But it is closely related to iron in the sesquioxide state, so that, using the same mode of expression as for iron, 1 of Al replaces 1 of Fe 3 , or 1 of Mjk, and so on. Similarly, writing R for any metal, 1 of R replaces 1 of R 3 . Again, in potash (K 2 O), soda (Na 2 O), lithia (Li.,O), water (H 2 O), one of oxygen (O) is combined severally with 2 of K (potassium), of Na (sodium), of Li (lithium), of hydrogen ; And hence 2K, 2Na, 2Li, that is, K 2 , Na 2 , Li 2 , may each replace in compounds ICa, or IMg, etc. The elements potassium, sodium, lithium, hydrogen, of which it takes two parts to combine with 1 of oxygen, are called monads. Other elements of the group of monads are rubidium, ccesium, thallium, silver, and also fluorine, chlorine, bromine, iodine. Still other elements combining by two parts in their oxygen or sulphur compounds, etc., are nitrogen, phosphorus, CHEMICAL COMPOSITION OF MINERALS. 79 intimony, boron, columbium, tantalum, vanadium, gold. For example, for arsenic there are the compounds As 2 S, A.8 S S 3 , &s 2 O 3 , As,,O 5 , etc. Another characteristic of these elements of the hydrogen, sodium, chlorine, and arsenic groups is that the number of equivalents of the acidic element in the compounds into which they enter is, with a rare exception, odd, and of the 1, 3, 5, etc., series, and on this account they are called in chemistry perissads while the other elements, in whose com- pounds their number is of the 1, 2, 3, etc. (or 2, 4, 6) series, are called artiads. An apparent exception exists under the artiads in the sesqui oxides, but this does not alter the general character of the series. The facts above cited sustain the general statement that Ca 3 , Mg 3 , Mn 3 , Zn 3 , Fe 3 , Al, Fe, Mn, have equivalent combin- ing values, and hence in minerals often replace one another ; and so also Ca, Mg, Mn, Zn, Fe, K 2 , Na 2 , Li 2 , H 2 , may replace one another. Similarly, also, As 2 , or Sb 3 replaces S in some minerals. With reference to the classification of minerals the elements may be conveniently divided into two groups: (1) the Acidic, and (2) the Basic. The former includes oxygen and the ele- ments which were termed the acidi/iers and acidiftable elements in the old chemistry. They are those which have been called in mineralogy the mineralizing elements, since they are the elements which are found combined with the metals to make them ores, that is, to mineralize them. The basic are the rest of the elements. The groups overlap somewhat, but this need not be dwelt upon here. The more important of the acidic elements are the following : oxygen, fluorine, chlorine, bromine, iodine, sulphur, selenium, tellurium, boron, chromium, molybdenum, tungsten, phosphorus, arsenic, antimony, vanadium, nitrogen, tantalum, columbium, carbon, silicon. Again, among the compounds of these elements occurring in tho mineral kingdom there are two grand divisions, the binary and the ternary. The binary consist of one or more elements of each of the acidic and basic divisions, and the ternary of one or more elements of each of these two classes, along with oxy- gen, fluorine, or sulphur as a third. The binary include the sulphides, arsenides, chlorides, fluorides, oxides, etc., and tho ternary the sulphates, chromates, borates, arsenates, pliospliates^ silicates, carbonates, etc., and also the sulpli-arsenites and sulph antimonites, in which a basic metal (usually lead, copper, sil- ver) is combined with arsenic or antimony and sulphur. 80 CHEMICAL PROPERTIES OF MINERALS. The following are examples of the symbols of binary imd ternary compounds : 1. Binary. 1. Sulphides, Selenides. Ag 2 S = silver sulphide; Ag 2 Se = silver selenide ; PbS = lead sulphide ; ZnS = zinc sulphide ; FeS 2 -- iron disulphide. 2. Fluorides, Chlorides, etc. CaF 2 = calcium fluoride ; AgCl = silver chloride ; AgBr = silver bromide ; AgT = silver iodide ; Nad = sodium chloride (common salt). 3. Oxides. A1 2 O 3 = 3 ( Al^O) = aluminium sesquioxide ; A s 2 O 3 =. arsenic trioxide ; As.;O 5 arsenic pentoxide ; BaO = barium oxide ; B.,O 3 = boron trioxide (boracic acid) ; CaO = calcium oxide (lime) ; CO 2 = carbon dioxide (carbonic acid) ; CrO 3 = chromium trioxide (chromic acid) ; Cu 2 O = copper sub- oxide ; CuO = copper oxide ; BeO = beryllium oxide ; H 2 O = hydrogen oxide (water) ; FeO = iron oxide ; Fe 2 O 3 = iron sesquioxide ; PbO lead oxide ; Li 2 O = lithium oxide ; MgO = magnesium oxide ; MnO = manganese oxide ; Mn 2 O 3 manganese sesquioxide ; MnO 2 = manganese dioxide ; P 2 O 5 = phosphorus pentoxide ; K 2 O potassium oxide ; SiO 3 = silicon dioxide (silica) ; Na 2 O = sodium oxide ; SrO = strontium ox- ide ; SO., sulphur dioxide (sulphurous acid) ; SO 3 = sulphur trioxide ; SnO 2 = tin dioxide ; V 2 O 5 = vanadium pentoxide (vanadic acid) ; WO 3 = tungsten trioxide (tungstic acid) ; ZnO = zinc oxide ; ZrO 2 zirconium dioxide. The composition of these compounds may be obtained from the table of combining weights, page 76. For example, with reference to the first of them (AgS), the table gives for the combining weight of silver (Ag), 108, and for that of sulphur, 32. The elements exist in the compound therefore in the proportion of 108 to 32, and from it the composition of a hundred parts ia easily deduced. If the formula were (Ag, Pb)S, signifying a silver- and- lead sulphide, and if the silver and lead were in the ratio of 1 to 1, than half the combining weight of silver is taken; that is, 54, and half the atomic weight of lead, which is 103 -5 ; and the sum of these numbers, with 32 for the sulphur, expresses the ratio of the three ingredients. For A1 2 O 3 we find the combining weight of aluminium 27. 4 ; doubling this for A1 2 makes 54*8. Again, for oxygen, we find 16 ; and three times 16 is 48. 54'S to 48 is therefore the ratio CHEMICAL COMPOSITION OF MINERALS. 81 of aluminium to the oxygen in A.l.jO 3 , from which the percent- age proportion may be obtained. 2. Ternary Oxygen Compounds. Silicates. Of these compounds there are two prominent groups. In one of these groups the general formula is RO 3 Si, and in the other R 4 O 4 Si. In both of these formulas R stands for any basic elements in the protoxide state, as Ca, Mg, Fe, etc., either alone or in combination. In the first of these for- mulas the combining values of the basic element R and the acidic element or silicon, as measured by their combinations with oxygen, are in the proportion of 1 to 2, for R stands for an element in the protoxide state, while Si stands for sili- con, which is in the dioxide state, its oxide being a dioxide and hence the minerals so constituted are called Itisilicates. Ii the second of these formulas this ratio is 2 to 2, or 1 to 1, and hence these are called Unisilicates. Multiplying these formulas by 3, they become R 3 O 8 Si 3 , and (2R 3 ) OjoSig ; and the same composition is expressed. In this form the substitution of sesquioxide bases for protoxide may be indicated : thus, R a R Oi a Si 3 signifies that half of the 2R 3 is re- placed by Al or Fe, or some other element in the sesquioxide state. There are also some species in which the ratio is 1 to less than 1, and these are called Subsilicates. The ratio here referred to (formerly known as the oxygen ratio) is called the quantivalent ratio. The other ternary compounds require no special remarks in this place. 2. CHEMICAL REACTIONS. 1. Trials in the wet way. 1. Test for Carbonates. Into a test tube put a little hydro- chloric acid diluted with one half water, and add a small por- tion in powder of the mineral. If a carbonate, there will be a brisk effervescence caused by the escape of carbonic dioxide (carbonic acid), when heat is applied, if not before. With cal- cium carbonate no heat or pulverization is necessary. 2. Test for Gelatinizing /Silica. Some silicates, when pow 6 82 CHEMICAL PROPERTIES OF MINERALS. tiered and treated with strong hydrochloric acid, are decom- posed and deposit the silica in a state of a jelly. The experi- ment may be performed in a test tube, or small glass flask. Sometimes the evaporation of the liquid nearly to dryness is necessary in order to obtain the jelly. Some silicates do not afford the jelly unless they have been previously ignited before the blowpipe, and some gelatinizing silicates lose the power on ignition. 3. Decomposability of Minerals by Acids. To ascertain whether a mineral is decomposable by acids or not, it is very finely powdered and then boiled with strong hydrochloric acid, or, in case of many metallic minerals, with nitric acid. In some cases where no jelly is formed there is a deposit of silica in fine flakes. With the sulphides and nitric acid there is often a deposit of sulphur, which usually floats upon the surface of the fluid as a dark spongy mass. Some oxides, and also some sulphates and many phosphates, are soluble entirely without effervescence. But many minerals resist decomposition. It is sometimes difficult to toll whether a mineral is decomposed with the separation of the silica or whether it is unacted upon. In such a case a portion of the clear fluid is neutralized by soda (sodium carbonate), and if anything has been dissolved it will usually be precipitated. Test for Fluorine. Most fluorides are decomposed by strong heated sulphuric acid, give out fluorine which will etch a glass plate in reach of the fumes. The trial may be made in a lead cup and the glass put over it as a loose cover. 2. Trials with the Blowpipe. The blowpipe, in its simplest form, is merely a bent tube of small size, eight to ten inches long, terminating at one end in a minute orifice. It is used to concentrate the flame on a min- eral, and this is done by blowing through it while the smaller end is just within the flame. The annexed figure represents the form commonly employed, except that the tube is usually without the division at b. ft contains an air chamber (o) to receive the moisture which ia condensed in the tube during the blowing ; the moisture, unless thus removed, is often blown through the small aperture and interferes with the experiment. The jet, e/, is movable, and it is desirable that it should be made of platinum, in order that it may be cleaned when necessary, either by high heating or CEEMICAL COMPOSITION OF MINERALS. 83 _y immersion in an acid. The screw at b is for the purpose of shortening the tube one-half so as to make it more convenient for the pocket of the field mineralogist. It is un- screwed for this purpose, and the smaller part put within the larger. In using the blowpipe it is necessary to breathe and blow at the same time, that the operator may not interrupt the flame in order to take breath. Though seemingly absurd, the necessary tact may easily be acquired. Let the student first breathe a few times through his nostrils while his cheeks are inflated and his mouth closed. After this practice lot him put the blowpipe to his mouth and he will find no difficulty in breathing as before while the muscles of the inflated cheeks are throwing the air thiy contain through the blowpipe. When the air is nearly exhausted the mouth may again be filled through the nose without interrupting the process of blowing. The flame of a candle, or a lamp with a large wick may be used, and when so it should be bent in the direction the flame is to be blown. But it is far better, when gas can be had, to use a Bunsen's burner. The flame has the form of a cone, yellow without and blue within. The heat is most intense just beyond the extremity of the blue flame. In some trials it is necessary that the air should not be excluded from the mineral during the experiment, aud when this is the case the outer flame is used. The outer is called the oxidizing flame (because oxygen, one of the consti- tuents of the atmosphere, combines in many cases with some parts of the assay, or substance under experiment), and the in- ner the reducing flame. In the latter the carbon and hydrogen of the flame, which are in a high state of ignition, and which are einloeed from the atmosphere by the outer flame, tend to unite with the oxygen of any substance that is inserted in it. Hence substances are red-iced in it. The mineral is supported in the flame either on charcoal; or \ -f means of steel forceps (as in the annexed figure) with plati- num extremities (a 6), opened by pressiu^r on the pins pp\ or on platinum wire or foil. 84 CHEMICAL PROPERTIES OF MINERALS. To ascertain the fusibility of a mineral, the fragment for the platinum forceps should not be larger than the head of a pin, and, if possible, should be thin and oblong, so that the extrem- ity may project beyond the platinum. The fusible metals alloy readily with platinum. Hence compounds of lead, arsenic, an- timony, etc., must be guarded against. These compounds are tosted 011 charcoal. The forceps should riot be used with the 'luxes, but instead either charcoal or the platinum wire or foil. The charcoal should be firm and well burnt ; that of soft wood is the best. It is employed especially for the i eduction of oxides, in which the presence of carbon is often necessary, and also for observing any substances whicb may pass off and be deposited on the charcoal around the assay. These coatings are usually oxides of the metals, which are formed by the oxi- dation of the volatile metals as they issue from the reduction flame. The platinum wire is employed in order to observe the ac- tion of the fluxes on the mineral, and the colors which the oxides impart to the fluxes when dissolved in them. The wire used is No. 27. This is cut into pieces about three inches long, and the end is bent into a small loop, in which the flux is fused. This makes what is called a bead. When the experiment is complete the beads are removed by uncoiling the loop and draw- ing the wire through the finger nails. After use for awhile the end breaks off, because platinum is acted upon by the soda, and then a new loop has to be made. Dilute sulphuric acid will remove any of the flux that may remain upon it after a trial has been made. Glass tube is employed for various purposes. It should be from a line to a fourth of an inch in bore. It is cut into pieces four to six inches long, and used in some cases with both ends open, in others with one end closed. In the closed tube, either heated directly over the Bunsen burner, or with the aid of the blowpipe, volatile substances in the assay are vaporized and condensed in the upper colder part of the tube, where they may be examined by a lens if necessary, or by further heating. The odor given off may also be noted, and the acidity of any ftimeF bj inserting a small strip of litmus paper in the mouth of the tube. The closed tube is used to observe all the effects tlv*t may take place when a substance is heated out of contact with the air. In the open tube the atmosphere passes through the tube in the heating, and so modifies the result. The assay is placed an inch or an inch and a quarter from the lower end of the tube ; the tube should be held nearly horizontally, to BLOWPIPE REACTIONS. 85 prevent the assay from falling out. The strength of the draught depends upon the inclination of the tube, and in special cases it should be inclined as much as possible. The most common fluxes are borax (sodium bi-borate), salt of phosphorus (sodium and ammonium phosphate), and soda (sodium carbonate, either the carbonate or bi-carbonate of soda of the shops.) These substances, when fused and highly heated, arc very powerful solvents for metallic oxides. They should be pure preparations. The borax and soda are much the most important. In using the platinum wire, the loop may be highly heated, and then a portion of the borax or soda may be taken up by it, and by successive repetitions of this process the re- quisite amount of the flux may be obtained on the wire. Then, by bringing the melted flux of the loop into contact with one or more grains of the pulverized mineral, the assay is made ready for the trial. With soda and quartz a perfectly clear globule is obtained, cold as well as hot, if the flux is used in the right proportion. Some oxides impart a deep and charac- teristic color to a bead of borax. In other cases the color obtained is more characteristic when salt of phosphorus is em- ployed. The color obtained in the outer flame is often differ- ent from that which is obtained in the inner flame. The beads are sometimes transparent and sometimes opaque. If too much substance is employed the beads will be opaque when it is de- sired that they should be transparent. In such cases the experiment may be repeated with less substance. In many cases pulverized mineral and the flux, a little moistened, are mixed together into a ball upon charcoal, especially in the ex- periments with soda. In the examination of sulphides, arsenides, antimonides and related ores, the assay should be roasted before using a flux, in order to convert the substance into an oxide. This is done by spreading the substance out on a piece of charcoal and exposing it to a gentle heat in the oxidizing flame. The sulphur, arsenic, antimony, etc., then pass off as oxides in the form of vapors, leaving the non-volatile metals behind as oxides. The escap- ing sulphurous acid gives the ordinary odor of burning sulphur ; arsenous acid, from arsenic present, the odor of garlic, or au alliaceous odor ; seleuous acid, from selenium present, the odor of decaying horse-radish ; while antimony fumes are dense white, and have no odor. The following is the scale of fusibility which has been adopted, beginning with the most fusible : 1. STIBNITE. Fusible in large pieces in tUe candle flame. 86 CHEMICAL PROPERTIES OF MINERALS. 2. NATROLITE. Fusible in small splinters iii the candle flame. 3. ALMANDINE, or bright red GARNET. Fusil ie in large pieces with ease in the blowpipe flame. 4. ACTINOLITE. Fusible in large pieces with difficulty in tho blowpipe flame. 5. ORTHOCLASE, or common feldspar. Fusible in small splinters with difficulty in the blowpipe flame. 6. BUONZITE. Scarcely fusible at all. The color of the flame is an important character in connection with blowpipe trials. When the mineral contains sodium tho color of the flame is deep yellow, and this is generally true in spite of the presence of other related elements. When sodium (or soda) is absent, potassium (or potash) gives a pale violet color; calcium (or lime) a pale reddish yellow ; lithium, s, deep purple -red, as in lithia-inica ; strontium, a bright red, this ele- ment being the usual source of the red color in pyrotechny ; copper, emerald green ; phosphates, bluish green ; boron, yellow- ish green ; copper chloride, azure blue. Beads should be exam- ined by daylight only, and should be held in such position that Mie color is not modified by green trees or other bright objects when examined by transmitted light. Colored flames are seen to best advantage when some black object is beyond the flame in the line of vision. It is also to be noted, in the trials, whether the assay heats up quietly, or with decrepitation ; whether it fuses with effer- vescence or not, or with intumescence or not ; whether it fuses to a bead which is transparent, clouded, or opaque ; whether blebby (containing air-bubbles or not) ; whether scoria-like or not. Testing for Water. The powdered mineral is put at the bottom of a closed glass tube, and after holding the extremity for a moment in the flame of a Bunsen's burner, moisture, if tiny is present, will have escaped and be found condensed on the inside of the tube, above the heated portion. Litmus or tur- meric paper is used to ascertain if the water is acid or alkaline, acids changing the blue of litmus paper to red, and alkalies the yellow of turmeric paper to brown. Testing for an Alkali. If the fragment of a mineral, heated in the platinum forceps, contains an alkali, it will often, after being highly heated, give an alkaline reaction when placed, after moistening, on turmeric paper, turning it brown. This lest is applicable to those salts which, on heating, part with a portion of their acid and are rendered caustic thereby. Such BLOWPIPE REACTIONS. 87 we the carbonates, sulphates, nitrates, and chlorides of the alkaline metals. Testing for Alumina or Magnesia, Cobalt nitrate, in solu- tion, is used to distinguish an infusible and colorless mineral containing aluminium from one -containing magnesium. A fragment of the mineral is first ignited, and then wet with a drop or two of the cobalt solution and heated again. The alu- minium mineral will assume a blue color, and the magnesium mineral a pale red or pink. Any fusible silicate, when moistened with cobalt nitrate and ignited will assume a blue color, hence this test is only deci- bive in testing infusible substances. Infusible zinc compounds, when moistened with cobalt nitrate, assume a green color. Testing for Lithium. Some lithium minerals give the bright purple-red flame if simply heated in the platinum for- ceps. In other cases mix the powdered mineral with one part of fiuorite and one of potassium bi-sulphate. Make the whole into a paste with a little water, and heat it on the platinum wire in the blue flame. Testing for Boron. When the bright yellow-green of boron is not obtained directly on heating the mineral containing it, one part of the powdered mineral should be mixed with ono part of powdered fluorite and three of potassium bi-sulphate ; and then treated as in the last. The green color appears at the instant of fusion. Testing for Fluorine. To detect fluorine in fluorides mix a little of the powdered substance with potassium bi-sulphate, put the mixture in a closed glass tube and fuse gently. The bi-sulphate gives oft* half of its sulphuric acid at a high temper- ature, which acts powerfully on anything it can attack. If a fluoride is present, hydrofluoric acid will be given off, and the walls of the tube will be found roughened and etched when the tube is broken open and cleaned after the experiment. If a silicate containing fluorine be powdered and mixed with previ- ously fused salt of phosphorus, and heated in the open tube by blowing thb flame into the lower end of the tube, hydrofluoric acid is given off, and the tube is corroded just above the assay. Silicates. Nearly all silicates undergo decomposition with salt of phosphorus, setting free the silica, forming a bead which is clear while hot and has a skeleton of silica floating in it, The bead is sometimes clear also when cold. Iron. Minerals containing much iron produce a magnetic globule when highly heated. Usually the reducing flame ia 88 CHEMICAL PROPERTIES OF MINERALS. required, and sometimes the use of soda. With borax iron gives a bead with the oxidizing flame which is yellow while hot, but colorless on cooling, and which in the reducing flame becomes bottle green. Cobalt. Minerals containing cobalt afford, with borax, a beautiful blue bead. If sulphur or arsenic is present it should be first roasted off on charcoal. Nickel. In the oxidizing flame with borax, the bead i? violet when hot, and red-brown on cooling. In the reducing flame the glass becomes gray and turbid from the separation of metal- lic nickel, and on long blowing, colorless. The reaction is ob- scured by the presence of cobalt, iron, and copper. Manganese. With borax in the oxidizing flame, the bead is a deep violet-red, and almost black if too much of the mineral is used. To see the color examine by transmitted light. With soda in the same flame the opaque bead is bluish green. Chromium. With borax, both in the oxidizing and reducing flame, the bead is bright emerald green. Titanium. Titanium oxide with salt of phosphorus on platinum Avire in O.F. dissolves to a clear glass, which, if much is present, becomes yellow while hot and colorless on cooling; but in R.F. the hot globule obtained in O.F. reddens and assumes finally a beautiful violet color. On charcoal with tin the glass becomes violet if there is not too much iron present. Zinc. Zinc and some of its compounds when heated cover the charcoal with zinc oxide, which is yellow while hot, but white on cooling ; and this coating, if wet with cobalt solution and then heated, assumes a fine yellowish-green color which is most distinct when cold. Lead., copper, tin, silver, when characterizing a mineral, give with soda in the reducing flame minute metallic globules, which are malleable, or may be cut with a knife ; they can be distin- guished by their well-known physical properties. When two or more of these metals occur together, or iron is also present^ the globules consist usually of an alloy of the metals. Lead. When the mineral is treated with soda on charccal in the oxidizing flame, the yellow oxide coats the charcoal around the assay. Copper. The flame is colored, in most cases, bright green. With borax or salt of phosphorus in the reducing flame the bead is red. In the oxidizing flame the bead is green when hot and becomes blue or greenish blue on cooling. Mercury. Heated in the closed tube with soda, a sublimate of metallic mercury covers the inside of the tube. BLOWPIPE REACTIONS. 89 Silver. If the silver is in very small quantities, as in argen- tiferous galena, the assay is put into a little cup made of bone ashes (bone burnt white and finely pulverized), and subjected to the oxidizing flame ; the lead is oxidized and sinks into the bone ashes, leaving the silver a brilliant globule on the cupeL Before cupellation it is often necessary to melt the assay to- gether with some borax and pure lead in a hole on charcoal. By this process the sand and impurities are removed, and a globule of lead is obtained which contains all the silver, and which may be separated from the slag and be oxidized as above. Arsenic. In the closed tube arsenic sublimes and coats the tube with brilliant grains, or a crust, of metallic arsenic. If the mineral contains sulphur as well as arsenic, sublimates of the yellow and red arsenic sulphides (orpiment and realgar) are often formed. In the open tube a sublimate of white arsenous acid is formed, Avhich condenses in bright crystals on the walls of the tube, and a strong garlic odor is given off. On charcoal the alliaceous odor is at once perceptible. Antimony. In the closed tube, when sulphur is present, the assay yields a sublimate which is black when hot, brown-red when cold. In the open tube dense white vapors are given off and a white amorpJwus sublimate covers the inside of the tube, which, for the most part, does not volatilize when reheated. On charcoal the assay yields dense, white, inodorous fumes. Tellurium. In the open tube a white or grayish sublimate is obtained, which may be fused to clear, colorless drops. Ou charcoal a white coating is produced, and the reducing flame is colored green. Sulphur. All sulphates, and other sulphur-bearing miner- als, when heated on charcoal with soda, produce a dark, yellow- ish brown sulphide of sodium ; and if a fragment of this is moistened and placed on a polished plate of silver, it turns it immediately brownish black, or black. Pure soda, and a flame wholly free from sulphur, is needed for the trial, since the least trace of sulphur in either vitiates the result. Many sulphides give fumes of sulphur on charcoal. The higher sulphides afford these fumes in a closed tube. The others afford fumes of sul- phurous acid in an open tube, which redden a moistened bluo litmus paper placed in the upper end of the tube. Selenium. Selenium and many selenides afford a steel-gray sublimate in an open tube, which at the upper edge appears red. On charcoal brown fumes are given off with an odor like that of decaying h( rse-radish. 90 CHEMICAL PROPERTIES OF MINERALS. Chlorides. If a bead of borax be saturated with copper oxide, and then dipped into the powder of a substance which ia to be tested for chlorine, a chloride of copper is formed which imparts an azure blue color to the flame if any chlorine is pres- ent. If dissolved in water or nitric acid a little silver nitrate produces a dense white precipitate of silver chloride. Nitrates. A nitrate, if fused on charcoal, will defkgrate with brilliancy, owing to the decomposition of the nitrate and the union of its oxygen with the carbon. Phosphates. Phosphates give a dirty green color to the blow- pipe flame. The color is more distinct if the substance is first moistened with sulphuric acid. If a phosphate is pulverized and heated in a closed glass tube with some bits of magnesium wire, the phosphoric acid is reduced, and when the fusion is moistened with water the very disagreeable odor of phosphuretted hydrogen is obtained. For a fall account of blowpipe reactions recourse must be had to a treatise on the blowpipe. The best and fullest Ameri- can work on the subject is Prof. Gr. J. Brush's " Manual of De- terminative Mineralogy, with an Introduction on Blowpipe Analysis." In this work the following abbreviations are used in speaking )f blowpipe reactions : B.J3. = before the blowpipe ; O.F. = oxidizing flame ; R.F. = reducing flame. CLASSIFICATION. 93 4. DESCRIPTIONS OF MINERALS. CLASSIFICATION. SOME of the prominent points in the classification of minerals adopted in the following pages are given in connection with the remarks on chemical composition, pages 79. Many instructors in the science, and most of those who con- sult a work on Mineralogy for practical purposes, prefer an ar- rangement of the ores which groups them under the head of the metal prominent in their constitution. The method of group- ing mineral species according to the basic element has therefore been here, to a large extent, followed. An exception has been made in the case of the silicates, because it is with them almost impracticable, on account of the number of basic elements they often contain ; and, moreover, not more than half a dozen use- ful ores exist among them. The silicates therefore, which in- clude the larger part of all minerals, make together one of the grand divisions in the classification, and they are presented ac- cording to their natural groups, in the same order as in the larger mineralogy. The prominent subdivisions in the classification are as fol- lows : I. THE ACIDIC DIVISION, including the acidic elements oc- curring native, and the native compounds of the acidic elements with one another. II. THE BASIC DIVISION, including the basic elements occur- ring native, and the native binary and ternary compounds of the basic elements the silicates excepted. III. SILICA and the SILICATES. IV. THE HYDROCARBON COMPOUNDS, including mineral oils, resins, wax, and coals. The following are the chief subdivisions under these head : I. ACIDIC DIVISION. 1. Sulphur Group. The chief oxide a trioxide, its formula K O 3 . Includes Sulphur and sulphur oxides ; Tellurium and tellurium oxides; Molybdenum sulphide and oxide; Tungsten oxide. 92 DESCRIPTIONS OF MINERALS. 2. Boron Group. The chief oxide a trioxide, its formula R 2 O 3 . Includes compounds of Boron with oxygen. 3. Arsenic Group. The chief oxide a pentoxide, its formula E,O 5 . Includes Arsenic arid arsenic sulphides and oxides ; An- tii.iony and antimony sulphide, arsenide and oxides ; Bismuth and bismuth sulphide, telluride and oxide. 4. Carbon Group. The chief oxide a dioxide, its formula R O. 2 . Includes Carbon (Diamond, Graphite) and carbon diox- ide. (Quartz, Si O. 2) belongs here chemically, but is placed with the Silicates.) II. BASIC DIVISION. Gold ; Silver ; Platinum and Iridium ; Palladium ; Quick- silver ; Copper ; Lead ; Zinc ; Cadmium ; Tin ; Titanium ; Co- balt and Nickel ; Uranium ; Iron ; Manganese ; Aluminium ; Cerium, Yttrium, Lanthanum, Didymiurn and Erbium ; Mag- nesium; Calcium; Barium and Strontium; Potassium and Sodium ; Ammonium ; Hydrogen. III. SILICA AND SILICATES. 1. Silica. 2. Anhydrous Silicates. 1. Bisilicates. 2. Unisilicates. 3. Subsilicates. 3. Hydrous Silicates. 1. General section of Hydrous Silicates. 2. Zeolite section. 3. Margarophyllite section. IV. HYDROCARBON COMPOUNDS. 1. Oils, Resins, Wax. 2. Asphaltum, Coals. GENERAL REMARKS ON ORES. An ore, in the miueralogical sense of the word, is a mineral compound in which a metal is a prominent constituent. In the GENERAL REMARKS ON ORES. 93 miner's use of the term it is a mineral substance that yields, by metallurgical treatment, a valuable metal, and especially when it profitably yields such a metal. In the former sense, galena, the common ore of lead, is, if it contains a little silver, an argentiferous lead-ore ; while, in the latter, if there is silver enough to make its extraction profitable, it is a silver-ore. Further than this, where a native metal, or other valuable metallic, mineral, is distributed intimately through the gangue, the mineral and gangue together are often called the ore of the metal it produces. We have beyond to do with ores only in the mineralogical sense. Ores are compounds of the metals, not metals in the native state. The more common kinds are compounds of the metala with Sulphur (sulphides) ; with Arsenic (arsenides) ; with Sul- phur and Arsenic (sulph-arsenides) ; with sulphur in ternary combination along with arsenic, antimony or bismuth (making compounds called sulph-arsenites, sulph-antimonites, sulpho-bis- mutites) ; with Selenium (selenides) ; with Tellurium (tellu- rides) ; with Oxygen (oxides) ; with Chlorine, Iodine, or Bro- mine (chlorides, iodides, or bromides) ; with oxygen in ternary combination with carbon (making carbonates) ; with Sulphur (making sulphates) ; with Arsenic (making arsenates) ; with Phosphorus (making phosphates) ; with Silicon (making sili- cates). Gold and platinum are, with rare exceptions, found only na- tive, or intimately mixed in essentially the pure state with some metallic minerals. Tellurium is the only acidic element that occurs combined with gold in nature. Silver is found in the state of sulphide, antimonide, selenide, telluride, sulph-arsenites and sulph-antimonites, but never as oxide or in oxygen ternary compounds. Quicksilver occurs in the state of sulphide (the common ore) ; also in that of selenide and sulph-arsenites. Copper and lead occur in the state of sulphides (common ores), arid also in all the binary and ternary states mentioned above. Zinc is known in the state of sulphide (very common), ojddo, carbonate, sulphate, silicate (all, excepting the sulphate, valuable as ores) ; and Cadmium in that of sulphide only. Tin occurs in the state of oxide (the common ore), and sul- phide. Cobalt and Nickel occur in the states of sulphide, arsenide, sulph-arsenides, antimonide, oxide, sulphate, arsenate, carbon- ate ; and nickel in that also of a silicate. 94 DESCRIPTIONS OF MINERALS. Iron occurs in the state of sulphide (very common, but not useful as an ore of iron), of arsenide, sulph-arsenide, oxide (the common ores of iron), carbonate (useful ore), sulphate, arsen- ate, phosphate, silicate. Manganese occurs in the state of sulphide (rare), arsenide (rare), oxide (the common ores), carbonate, sulphate, phosphate^ silicate. 1. MINEKALS CONSISTING OF THE ACIDIC ELEMENTS. Oxygen might properly be included in this section, since it occurs native in the atmosphere mixed with nitrogen, consti- tuting 21 per cent, of it. But this mention of it is all that ia necessary. The ternary compounds, in which, as in sulphuric acid, hydrogen is the basic element, are here included. Chlor* ine, bromine, and iodine do not occur native, and neither do their oxides, nor any compounds with acidic elements, and hence these elements are not represented under this division. The same is true of selenium and chromium of the sulphur group, and of vanadium, tantalum, and columbium of the arsenic group. I. SULPHUR GROUP. Native Sulphur. Trimetric. In acute octahedrons, and secondaries to thii form, with imperfect octahedral cleavage. 1 A 1 (in same pyra- 1. 2. mid) = 10(5 25' and 85 07'; lAl (over base) = H3 C 23'. Also massive. Color and streak sulphur-yellow, sometimes orange-yellow. BULPHUB. 95 Lustre resinous. Transparent to translucent. Brittle. H.= 1*5 2-5. G.= 2.07. Burns with a blue flame and sulphurous odor. In a closed tube it is wholly volatilized and redeposited on the wall of the tube. Native sulphur is either pure, or contaminated with clay or bitumen. It sometimes contains selenium, and has then an orange-yellow color. Diff. It is easily distinguished by its burning with a blue flame, and the sulphur odor then afforded. Obs. The great repositories of sulphur are either beds of gypsum and the associate rocks, or the regions of active or ex- tinct volcanoes. In the valley of Noto and Mazzai o in Sicily, at Conil near Cadiz in Spain, Bex in Switzerland, and Cracow in Poland, it occurs in the former situation. Sicily and the neighboring volcanic islands, Vesuvius and the Solfatara in its vicinity, Iceland, Teneriffe, Java, Hawaii, New Zealand, De- ception Island, and most active volcanic regions afford more or less sulphur. The native sulphur of commerce is brought largely from Sicily, where it occurs in beds along the central part of the south coast and to some distance inland. It under- goes rough purification by fusion before exportation, which separates the earth and clay with which it occurs. On the Potomac, twenty-five miles above Washington, sul- phur has been found associated with calcite in a gray com- pact limestone ; sparingly about springs where hydrogen sul- phide is evolved, in New York and elsewhere ; in cavities where iron sulphides have decomposed, and in many coal mines ; near Borax Lake, in California ; Inferno, Humboldt County, Nevada, abundant. The sulphur of commerce is also largely obtained from copper and iron pyrites, it being given off during the roasting of thee ores. Sulphur when cooled from fusion, or above 232 F., crys- tallizes in oblique rhombic prisms. When poured into water at a temperature above 300 F. it acquires the consistency of soft wax, and is used to take impressions of gems, medals, etc., which harden as the sulphur cools. The uses of sulphur for gunpowder, bleaching, the manufacture of sulphuric acid, and also in medicines, are well known. Sulphur occurs in various ores as sulphides and sulphates. Among the sulphides are pyrite, an iron sulphide ; pyrrhotite, another iron sulphide ; galena, a lead sulphide, the common ore of lead ; chalcopyrite, or yellow copper ore, a copper and iron sulphide; cinnabar, a mercury sulphide ; argentite, a silver sulphide, etc. 96 DESCRIPTIONS OF MINERALS. Sulphuric and Sulphurous Acids. Sulphuric acid is occasionally met with around volcanoes, and it is also formed from the decomposition of hydrogen sulphide about sulphur springs. It is intensely acid. Composition, Sulphur teroxide (SOJ 81*6, water 18-4=100, it being chemically hydrogen sul- phate. Occurs in the waters of Rio Vinagre, South America ; also in Java, and at Lake de Taal on Luzon, in the East Indies ; in Genesee Co., N. Y. ; and at Tuscarora, St. Davids, and elsewhere, Canada West. Sulphurous acid, or sulphur dioxide (S0. 2 ), is produced when sulphur burns, and causes the odor perceived during the combustion. It is common about active volcanoes. It destroys life and extinguishes combustion. Composition, Sulphur 50-00, oxygen 50-00. Native Tellurium. Hexagonal ; R/\R = 86 57'. Occurs sometimes in six-sided prisms with perfect lateral cleavage ; but is com- monly granular massive. Color and streak tin-white. Brit- tle. H. =2-2-5. G. =6-1-6 -3. Sometimes contains a little iron, and also a trace of gold. In an open tube, b. B. yields a w r hite inodorous sublimate, which may be fused to colorless transparent drops ; and on charcoal fuses and volatilizes, tinging the flame green, and covering the charcoal with white tellurium dioxide. Obs. Occurs in Hungary and Transylvania ; also, Boulder Co., Colorado, at the Red Cloud Mine ; in Magnolia District at the Keystone, Dun River, and other mines ; in the BaJ- lerat District at Smuggler Mine ; in Central District at the John Jay Mine, where masses of 25 pounds weight are re- ported to have been found. Tellurium is also a constituent of ores of silver and lead (pp. 118, 149), and these are the chief sources of the metal. Tellurite or Tellurous acid, Te0 2 , occurs at the Keystone, Smug- gler, and John Jay Mines ; especially the last, where it is in minute white or yellowish crystals having one eminent cleavage. Molybdenite. Molybdenum Sulphide. Hexagonal. In hexagonal plates, or masses, thin foliated, like graphite, and resembling that mineral. H.= 1-1-5. G. = 4-45-4-8. Color pure lead- gray ; streak the same, BORON GROUP. 9? slightly inclined to green. Thin laminae very flexible ; not elastic ; leaves a trace on paper, like graphite, but its color is slightly different, being bluish-gray. Composition. Mo S 2 = Sulphur 41-0, molybdenum 59*0= 100. B.B. infusible, but when heated on charcoal, sulphur fumes are given off, which are deposited on the coal. Dis- solves in nitric acid, excepting a gray residue. Diff. Resembles graphite, but differs in its paler color and streak, and also in giving fumes of sulphur when heated, as well as by its solubility in nitric acid. Obs. Occurs in granite, gneiss, mica schist, and allied rocks ; also in granular limestone. It is found in Sweden, at Arendal in Norway, in Saxony, Bohemia, at Caldbeck Fell in Cumberland, and in the Cornish mines. In the United States it occurs in Maine at Blue Hill Bay, Camdage Farm, Brunswick, and Bowdoinham ; in New Hampshire at Westmoreland, Landaff, and Franconia ; in Massachusetts at Shutesbury and Brimfield ; in Connecticut at Haddam and Saybrook ; in New York near Warwick ; in New Jersey near the Franklin Furnace. Molybdenum does not occur native. An oxide is occa- sionally found in yellow incrustations on molybdenite, as a result of its alteration. It occurs, combined with lead, as a molybdate (page 151), and this is the only native salt con- taining it. The name molybdenum is from the Greek mo- luMaina, meaning mass of lead, and alludes to the resem- blance of molybdenite to graphite. TUNGSTITE, or Tungstic ochre. A yellow powder or incrustation oc- curring with wolfram, and a result of its decomposition. Occasionally observed at Lane's Mine, Monroe, Conn. Besides this oxide there are tac native compounds, iron tungstate or wolfram (p. 183), lead tungstate (p. 151), and calcium tungstate. Tungsten also occurs sparingly in some ores of columbium, as in cer- tain varieties of the minerals pyrochlore, columbite, and yttro-colum- bite. II. BORON GROUP. In Boron, as in the Sulphur group, the most prominent oxide is a teroxide. Sassolite. Boracic Acid. Sassolin. Occurs in small scales, white or yellowish. Feel smooth and unctuous. Taste acidulous and a little saline and bitter. 98 DESCRIPTIONS OF MINERALS. G. =1*48. Composition, H 6 6 Bo 2 = Boron teroxide 56-4, water 43-6. It is strictly hydrogen borate. Fuses easily in the flame of a candle, tinging the name at first green. Found at the crater of Vulcano, and also at Sassoin Italy, whence it was called Sassolin. The hot vapors of the la- goons of Tuscany afford it in large quantities. The vapors are made to pass through water, which condenses them ; and the water is then evaporated by the steam of the springs, and boracic acid obtained in large crystalline flakes. It still requires purification, as the best thus procured contains but 50 per cent, of the pure acid. Occurs also in the waters of Lick Springs, Tehama Co., and Borax Lake, Lake Co., California, where it was first observed, through their evapo- ration, by Dr. J. A. Veatch, in 1856. It has since been obtained from the waters of Mono, Owens, and other lakes. It exists sparingly in the waters of the ocean. But in all these waters, it is probably in combination. Boron occurs usually in the condition of magnesium, calcium, and sodium borates (pp. 206, 212, 227) ; and rarely as an iron borate (p. 182), or ammonium borate (p. 231). It also occurs in the silicates, tourma- line, danburite, axinite, and datolite, in which it is easily detected by the blowpipe reaction (p. 87). III. THE ARSENIC GROUP. The elements of the Arsenic group occurring among minerals are, arsenic, antimony, bismuth, phosphorus, ni- trogen, vanadium, tantalum, columbium. Of these arsenic, antimony, and bismuth occur native, and as sulphides ; also, in combination with other metals, constituting arsenides, antimonides, bismutides ; and, along with sulphur also, mak- ing sulpharsenites, sulphantimonites, sulphbismutites. In addition, they all, excepting bismuth, enter into the consti- tution of a series of native ternary oxygen compounds or salts, called severally, arsenates, antimonates, phosphates, nitrates, vanadates, tantalates, columbates. The chief oxide has the general formula K 2 5 . Native Arsenic. Khombohedral. R/\R=85 41'. Cleavage basal, imper- fect. Also massive, columnar, or granular. THE ARSENIC GROUP. 99 Color and streak tin-white, but usually dark grayish from tarnish. Brittle. H.=3-5. G. =5-65-5-95. B.B. volatilizes very readily before fusing, with the odor of garlic ; also burns "with a pale bluish flame when heated just below redness. Obs. Occurs with silver and lead ores. It is found in considerable quantities at the silver mines of Freiberg and Sclmeeberg; also in Bohemia, the Hartz, at Kapnik in Upper Hungary, in Siberia in large masses, and elsewhere. In the United States it has been observed at Haverhill and Jackson, N. H., and at Greenwood, Me. Orpiment Yellow Arsenic Sulphide. Trimetric. Cleavage highly perfect in one direction. In foliated masses, and sometimes in prismatic crystals. Color and streak fine yellow. Lustre brilliant pearly, or metallic pearly, on the face of cleavage. Subtransparent to translu- cent ; sectile. H. = 1 -5-2. G. - 3 -4-3 -5. Composition. As 2 S 3 = Sulphur 39-0, arsenic 61*0. Wholly evaporates before the blowpipe with an alliaceous odor, and on charcoal burns with a blue flame. From Hungary, Koordistan in Turkey in Asia, China, and South America/ Occurs at Edenville, N. Y., as a yellow powder, resulting from the decompositon of arsenical iron. Realgar is another arsenic sulphide. It has a fine clear red color, aurora red to orange, and occurs transparent or translucent ; H. = 15-2; GK =335-3 65; Composition, As S= Sulphur 29 '9, arsenic 70'1. Like the preceding before the blowpipe. From Hungary, Bohemia, Saxony, the Hartz, Switzerland, and Koordistan in Asiatic Turkey. It has been observed in the lavas of Vesuvius. Realgar is one of the ingredients of white Indian fire, often used as a signal light. Orpiment is a coloring ingredient in the pigment called king's yellow, in which it is mixed with arsenious acid. Arsenolite. White Arsenic. Isometric. In minute capillary crystals, and botryoidal or stalactitic. Color white. Soluble ; taste astringent, sweetish. H.=l-5. G.=3'7. Composition. As 2 3 = Arsenic 75-8, oxygen 24-2 = 100. This is the same compound with the common arsenic of the shops. It is found but sparingly native, accompanying ores of silver, lead, and arsenic in the Hartz, Bohemia, and elsewhere. It is a well-known poison. 100 DESCRIPTIONS OF MINERALS. Claudetite is the same compound in trimetric crystallizations, from Portugal. General Remarks. Arsenic is obtained for commerce chiefly from arsenopyrite(ormispickel), an iron sulph-arsenide, and from the nickel and cobalt arsenides, by first roasting off the sulphur, and then con- densing the arsenic, in the state of As 2 O 3 (" arsenous acid ") in large chambers. To obtain the material pure it is usually sublimed again in iron pots, in the upper part of which (artificially kept cool) it is condensed, mostly in a half-fused vitreous condition. To reduce the oxide to the metallic state it is heated with charcoal. In Devon and Cornwall the arsenical ores occur with the tin ore, and a large amount of white arsenic is made. The metal arsenic forms a small part of some alloys ; the most important is that with lead for shot making. Native Antimony. Khombohedral ; Rf\RST 35'. Usually massive, with a very distinct lamellar structure ; sometimes granular. Color and streak tin-white. Brittle. H. = 3-3 -5. G-. = 6 -6-6 -75. Composition. Pure antimony, often with a little silver, iron, or arsenic. B. B. on charcoal fuses easily and passes off in white fumes. Obs. Occurs in veins of silver and other ores in Dauphiny, Bohemia, Sweden, the Hartz, and Mexico. Stibnite. Gray Antimony. Antimony Sulphide. Trimetric. In right rhombic prisms, with striated lateral faces ; / A/=90 45'. Cleavage in the direction of the shorter diagonal, highly perfect. Commonly diver- gent columnar or fibrous. Sometimes massive granular. Color and streak lead-gray ; liable to tarn- ish. Lustre shining. Brittle ; but thin lami- nae a little flexible. Somewhat sectile. II. =2. G. =4-5-4 -62. Composition. Sb 2 S 3 = Sulphur 28-2, anti- mony 71*8. Fuses readily in the flame of a candle. B. B. on charcoal it is absorbed, giv- ing off white fumes and a sulphur odor. Diff. Distinguished by its extreme fusibility and its vaporizing before the blowpipe. Obs. Stibnite occurs in veins with ores of silver, lead, zinc, or iron, and is often associated with barite, spathic iron, or quartz. It occurs at Felsobanya and Schemnitz in Hungary ; at Wolfsberg in the Hartz ; at Braunsdorf near Freiberg; in Auvergne, Cornwall, Spain, and Borneo. THE ARSENIC GROUP. 101 In the United States, it has been found sparingly at Car- mel, Me., Lyme, N. H., and at "Soldier's Delight," Md., in the Humboldt mining region, and in the mines of Aurora, Esmeralda County, Nevada. This ore affords much of the antimony of commerce. By simple fusion, the crude antimony of the shops is obtained,, from which pure antimony and its pharmaceutical prepara- tions are made. Allemontite is an arsenical antimony, Sb a As 3 , from Allemont, and also from Bohemia and the Hartz. Valentinite. White antimony in white, grayish, or reddish rect- angular crystals, with perfect cleavage, affording a rhombic prism of 130 58'. 'Also in tabular masses, and columnar and granular. H. = 2 '5-3. G. =5'57. Lustre adamantine to pearly. Composition, Sb 2 3 =Oxygen 16-44, antimony 83 56=100. Senarmontite is the same compound in isometric forms. Kermesite or red antimony is an antimony oxide and sulphide, in red tufts of capillary crystals. Lustre adamantine. From Hungary, Dauphiny, Saxony, and the Hartz. Cei-vantite. An oxide of antimony, Sb 2 O 4 , resulting from the de- composition of stibnite. Livingstonite. Like stibnite, but contains 14 per cent, of mercury and has a red streak. From Mexico. Native Bismuth. Ehombohedral ; R A E 87 40'. Cleavage rhombohedral, perfect. Generally massive, with distinct cleavage ; some- times granular. Color and streak silver white, with a slight tinge of red. Subject to tarnish. Brittle when cold, but somewhat mal- leable when heated. H. =2-2-5. G.=9'7-9-8. Fuses at a temperature of*76 F. Composition. Pure bismuth, with sometimes a trace of arsenic, sulphur or tellurium. B.B. on charcoal vaporizes, and leaves a yellow coating on the coal, paler on cooling. Obs. Native Bismuth is abundant with ores of silver and cobalt in Saxony and Bohemia, and occurs also in Cornwall and Cumberland, England. At Schneeberg, it forms arbo- rescent delineations in brown jasper. Occurs also in Nor- way, Sweden, Chili and Bolivia ; also at the Balhannah mine, in S. Australia, with copper ore and gold. In the United States, it has been found at Lane's and Booth's mine, Monroe, where it occurs with tungsten, galenite and pyrite ; also at Brewer's mine, in Chesterfield district, South Carolina ; and in Colorado. 102 DESCRIPTIONS OP MINERALS. Bismuthinite. A bismuth sulphide, Bia S 3 , in acicular crystals of a lead-gray color. G-uanajuatite. A bismuth selenide, from Guanajuato, Mexico, called also frenzelite. Silaonite is a selenide from the same locality, of a lead-gray color. Bismite. Bismuth ochre, an impure oxide, grayish, to greenish and yellowish white, and massive or earthy, found with native bismuth. Tetradymite. Bismuth Telluride. Hexagonal ; R A R = Sl 2'. Crystals often tubular, with a very perfect basal cleavage. Also massive, and foliated or granular. Laminae flexible, and soil paper. Lustre splendent metallic. Color pale steel-gray, a little sectile. H.= 1-52. G.=7;2 7 -9. Composition. Consists of bismuth and tellurium, with some- times sulphur and selenium, affording for the most part the formula Bi 2 (Te, S) 3 . A variety from Dahlonega, Georgia, gave Tellurium 48-1, bismuth 51'9 = Bi,Te 3 ; G. = 7>642. Joseite is a bismuth telluride from Brazil, in which half the bismuth is replaced by sulphur ; and WeJirlite is another containing sulphur, from Deutsch Pilsen, Hungary, having 8=8-44. Obs. Found with gold in Virginia, North Carolina, and Georgia ; Highland, Montana Territory ; Red Cloud Mine, Colorado ; Montgomery Mine, Arizona. General Remarks. The metal bismuth is obtained mostly from native bismuth. Besides the above ores, there are also others in which the metal is combined with silver, lead, and cobalt (pp. 116, 166) ; and a carbonate of bismuth, which occurs rarely in connection with native bismuth or the ores of the metal, as a result of oxidation ; also a silicate. IV. CARBON GROUP. The Carbon group in chemistry comprises carbon and silicon, in which the formula for the most prominent oxide is R 2 . Only carbon occurs native. Carbon occurs crystallized in the diamond and graphite ; as oxides, in carbon oxide, and carbon dioxide (ordinarily called carbonic acid); combined with hydrogen, or hydrogen and oxygen, in bitumen, mineral oils, amber, and a num- ber of native mineral resins, and mineral wax; and as the chief constituent of mineral coal, in which it is combined CARBON GROUP. 103 with more or less of hydrogen and oxygen and usually some nitrogen. Diamond. Isometric. In octahedrons, dodecahedrons and more com- plex forms. Faces often curved, as in the figures. Cleavage octahedral ; perfect. Color white, or colorless ; also yellowish, red, orange, green, blue, brown or black. Lustre adamantine. Trans- parent ; translucent when dark -colored. H. =10. Q.= 3.483-55. Composition. Pure carbon. It burns and is consumed at a high temperature, producing carbonic acid gas. Exhibits vitreous electricity when rubbed. Some specimens exposed to the sun for a while, give out light when carried to a dark place. Strongly refracts and disperses light. Diff. Diamonds are distinguished by their superior hard- ness ; their brilliant reflection of light and adamantine lustre, their vitreous electricity when rubbed, which is not afforded by other gems unless they are polished ; and, by the practiced ear, by means of the sound when rubbed together, Obs. The coarse diamonds, unfit for jewelry, are called tort, and the kind in black pebbles, or masses, from Brazil, carbonado. The latter occur sometimes in pieces 1,000 carats in weight ; they have G. =3 to 3 '42. Another kind is much like anthracite, Gr. = 1 -66, although as hard as diamond crystals ; it is in globules or mammillary masses, often partly made up of concentric layers. Diamonds occur in India, in the district between Golconda and Masulipatam, and near Parma, in Bundelcund, where some of the largest have been found ; also on the Mahanuddy, 104 DESCRIPTIONS OF MINERALS. in Ellore. In Borneo, they are obtained on the west side of the Ratoos Mountain, with gold and platina. The Brazilian mines were first discovered in 1728, in the district of Serra do Erio, to the north of Rio de Janeiro ; the most celebrated are on the river Jeqnitinhonha, which is called the Diamond River, and the Rio Pardo ; seventy to seventy-five thousand carats are exported annually from these regions. In the Urals of Russia they had not been detected till July, 1829, when Humboldt and Rose were on their journey to Siberia. The river Gunil, in the province of Constantine, in Africa, is reported to have afforded some diamonds. In South Africa, where they were first discovered in 1867, they occur in the gravel of the Vaal River, and in the Orange River country. The value of the diamonds obtained up to November, 1875, has been estimated as exceeding 60,000,000 of dollars. In the United States, the diamond has been met with in Rutherford County, North Carolina; Hall County, Georgia ; also Franklin County, North Carolina ; in Manchester, opposite Richmond, Virginia ; also in Cherokee Ravine, Butte County, Forest Hill in El Dorado County (one weigh- ing nearly 5 -62 grains), Fiddletown in Amador County, and in Nevada County, California; and on the coast of Southern Oregon. It has been reported from Idaho. The original rock in Brazil appears to be either a kind of laminated granular quartz, called itacolumyte ; or a ferru- ginous quartzose conglomerate. The itacolumyte occurs in the Urals, and diamonds have been found in it ; and it is also abundant in Georgia and North Carolina. In India, the rock is a quartzose conglomerate. The origin of the diamond has been a subject of speculation, and it is the prevalent opinion that the carbon, like that of coal and mineral oil, is of vegetable or animal origin. Some crystals have been found with black uncrystallized particles or seams within, looking like coal ; and this fact has been supposed to indicate such an origin. Diamonds, with few exceptions, are obtained from allu- vial Avashings. In Brazil, the sands and pebbles of the diamond rivers and brooks (the waters of which are drawn off in the dry season to allow of the work) are collected and washed under a shed, by a stream of water passing through a succession of boxes. A washer stands by each box, and inspectors are stationed at intervals. CARBON GROUP. 105 Diamonds are valued according to their color, transpa- rency and size. The rose diamond is more valuable than the pure white, owing to the great beauty of its color and its rarity. The green diamond is much esteemed on account of its color. The blue is prized only for its rarity, as the color is seldom pure. The black diamond, which is uncom- monly rare and without beauty, is highly prized by collec- tors. The brown, gray and yellow varieties are of much less value than the pure white or limpid diamond. The largest diamond of which we have any knowledge is mentioned by Tavernier, as in the possession of the Great Mogul. It weighed originally 900 carats, or 2,769-3 grains, but was reduced by cutting to 861 grains. It has the form and size of half of a hen's egg. It was found in 1550, in the mine of Colone. The diamond which formed the eye of a Braminican idol, and was purchased by the Empress Catherine II. of Russia from a French grenadier who had stolen it, weighs 194| carats, and is as large as a pigeon's egg. The Austrian crown has a diamond weighing 139 \ carats. The Pitt or Regent diamond is of less size, it weighing but 136-25 carats, or 419 grains ; but on account of its un- blemished transparency and color, it is considered the most splendid of Indian diamonds. It was sold to the Duke of Orleans by Mr. Pitt, an English gentleman, who was gover- nor of Beiicolen, in Sumatra, for 130,000. It is cut in the form of a brilliant, and is estimated at 125,000. The Rajah of Mattan has in his possession a diamond from Bor- neo, weighing 367 carats. The Koh-i-noor, on its arrival in England, weighed 186-016 carats.* It is said by Taver- nier to have originally weighed 787-J- carats. It has since been recut and reduced one-third in weight. In the Dresden Treasury there is an emerald green dia- mond, weighing 31J carats. The Hope diamond, weighing 44jL carats, has a beautiful sapphire-blue color. The diamonds of Brazil are seldom large. Maure men- tions one of 120 carats, but they rarely exceed 18 or 20. One weighing 254^ carats, called the "Star of the SoutJt," was found in 1854. Of South African diamonds, the " Schreiner" weighed, * A carat is a conventional weight, and is divided into 4 grains, which are a little ighter than 4 grains troy ; 74 1-1 <> carat grains nre equal to 72 troy grains. The term carat is derived from the name of a bean in Africa, which, in a dried state, has long been used in that country for weighing gold. These beans were early carried to India, and were employed there for weighing diamonds. 106 DESCRIPTIONS OF MINERALS. in its rough state, 308 carats ; and the " Stewart," which has a light straw color, 288-35 carats. The diamonds of South Africa are mostly "off col or; "about 10 per cent, are of first quality ; 15/2d ; 20, 3d ; and 55 per cent, are bort (W. J. Morton). The "Star of South Africa," of pure water, weighed 83-5 carats. Some crystals crack to pieces after being exposed to the air awhile. The diamond is cut by taking advantage of its cleavage, and also by abrasion with its own powder. The flaws are some- times removed by cleaving it. Afterwards the crystal is fixed to the end of a stick of soft solder when the solder is in a half-melted state, leaving the part projecting which is to be cut. A circular plate of soft iron is then charged with the powder of the diamond, and this, by its revolution, grinds and polishes the stone. By changing the position, other facets are added in succession till the required form is ob- tained. Diamonds were first cut in Europe, in 1456, by Louis Berquen, a citizen of Bruges ; but in China and India, the art of cutting appears to have been known at a very early period. By the above process, diamonds are cut into brilliant, rose and table diamonds. The brilliant has a crown or upper part, consisting of a large central eight-sided facet, and a series of facets around it ; and a collet, or lower part, of py- ramidal shapes, consisting of a series of facets, with a mailer series near the base of the crown. The depth of a brilliant is nearly equal to its breadth, and it therefore requires a thick stone. Thinner stones, in proportion to the breadth, are cut into rose and table diamonds. The surface of the rose diamond consists of a central eight-sided facet of small size, eight triangles, one corresponding to each side of the table, eight trapeziums next, and then a series of sixteen tri- angles. The collet side consists of a minute central octagon, surrounded by eight trapeziums, corresponding to the angles of the octagon, each of which trapeziums is subdivided by a salient angle into one irregular pentagon and two triangles. The table is the least beautiful mode of cutting, and is used for such fragments as are quite thin in proportion to the breadth. It has a square central facet, surrounded by two or more series of four-sided facets, corresponding to the sides of the square. Diamonds have also been cut with figures upon them. As early as 1500, Charadossa cut the figure of one of the Fathers of the church on a diamond, for Pope Julius II. CARBON GROUP. 107 Diamonds are employed for cutting glass; and for this purpose only the natural edges of crystals can be used, and those with curved faces are much the best. Diamond dust is used to charge metal plates of various kinds for jewelers, lapidaries and others. Those diamonds that are unfit for working, are sold for various purposes, under the name of lort. Drills are made of small splinters of bort, and used for drilling other gems, and also for piercing holes in artifi- cial teeth and vitreous substances generally ; and, others of iron set with a few diamonds, for drilling rocks. Graphite. Plumbago. Hexagonal. Sometimes in six-sided prisms or tables with a transversely foliated structure. Usually foliated, and mas- sive ; also granular and compact. Lustre metallic, and color iron-black to dark steel-gray. Thin lamina flexible. R. = l-2. G.=2'25-2-27. Sofia paper, and feels greasy. Composition. Commonly 95 to 99 per cent, of carbon. B.B. infusible, both alone and with reagents; not acted upon by acids. Diff. Kesembles molybdenite, but differs in being unaf- fected by the blowpipe and acids. The same characters dis- tinguish the granular varieties from any metallic ores they resemble. Obs. Graphite (called also black lead] is found in crys- talline rocks, especially in gneiss, mica schist and granular limestone ; also in granite and argillyte. Its principal Eng- lish locality at Borrowdale, in Cumberland, is now nearly exhausted. In the United States graphite occurs in large masses in veins in gneiss at Sturbridge, Mass. It is also found in North Brookfield, Brimfield and Hinsdale, Mass. ; abundant at Roger's Rock, near Ticonderoga ; near Fishkill Landing in Dutehess County ; at Rossie, in St. Lawrence County, and near Amity, in Orange County, N. Y. ; at Greenville, N. C. ; in Cornwall, near the Housatonic, and in Ashford, Ct. ; near Attleboro, in Bucks County, Penn. ; in Brandon, Vermont ; in Wake, North Carolina ; on Tyger River, and at Spartan- burg, near the Cowpens Furnace, South Carolina ; also abundantly and of excellent quality in Canada, in Bucking' ham, Fitzroy and Grenville. 108 DESCRIPTIONS OF MINERALS. For the manufacture of the best pencils the granular graphite was thought necessary, and hence the former great value of the Borrowdale mine, where the texture was pecu- liarly fine and firm. But now the graphite is ground up, and then compressed under heavy pressure, and thus the fine texture and firmness required may be obtained with any pure graphite. At Sturbridge, Mass., it is rather coarsely granular and foliated, and has been extensively worked. The mines of Ticonderoga and Fishkill Landing, N. Y. ; of Brandon, Vt. ; and of Wake, North Carolina, are also worked ; and that of Ash ford, Ct., formerly afforded a large amount of graphite, though now the works are suspended. Graphite is extensively employed for diminishing the friction of machinery ; also for the manufacture of crucibles and furnaces ; and as awash for giving a gloss to iron stoves and railings. For crucibles it is mixed with half its weight of clay. Carbonic Acid. Carbonic acid carbon dioxide of existing chemistry is the gas that gives briskness to the Saratoga and many other mineral waters, and to artificial soda water. Its taste is slightly pungent. It extinguishes combustion and destroys life. Composition. C 0,= Oxygen 72-35, carbon 27 -65 = 100. This gas is contained in the atmosphere, constituting about 4 parts, by volume, in 10,000 parts ; and it is present in minute quantities in the waters of the ocean and land. It is given out by animals in respiration, and is one of the re- sults of animal and vegetable decomposition ; and from this source the waters derive much of their carbonic acid. This gas is the choke-damp of mines, where it is often the occasion of the destruction of life. It is often present also in wells. Carbon dioxide (or carbonic acid) is given out by lime- stone (or calcium carbonate) when it is heated ; and quick- lime is limestone from which C ? has been expelled by heat, a process carried on usually in a limekiln. It is also driven from limestone by the action of sulphuric acid, with the for- mation of gypsum (a hydrous calcium sulphate), or anhy- drite (an anhydrous calcium sulphate). These processes are often carried on in volcanoes, and hence carbonic acid gas is common in some volcanic regions. The Grotto del Cane (Dog Cave) at the Solfatara near Naples; is a small cavern 109 filled to the level of the entrance with this gas. It is a com- mon amusement for the traveler to witness its effect upon a dog kept for that purpose-. He is held in the gas awhile and is then thrown out apparently lifeless ; in a few minutes he recovers himself, picks up his reward, a bit of meat, and runs off as lively as ever. If continued in the carbonic acid gas a short time longer, life would have been extinct. Carbonic acid, under high pressure, becomes a liquid, and, with pressure and cold, a white snow-like solid. In the liquid state it is often found in microscopic globules in the inte- rior of crystallized quartz, topaz, and some other mineials ; and when this is true, calcite (calcium carbonate) is often present in the same or an adjoining rock. Besides the calcium carbonate in nature, there are also carbonates of ammonium, sodium, barium, strontium, mag- nesium, iron, manganese, zinc, copper, lead, nickel, cobalt, bismuth, uranium, cerium, and lanthanum. II. MINERALS CONSISTING OF THE BASIC ELEMENTS WITH OR WITHOUT ACIDIC THE SILICATES EXCLUDED. I. GOLD. Gold occurs mostly native, being either pure, or alloyed with silver and other metals. It is occasionally found min- eralized by tellurium, making part of the valuable minerals Sylvanite, Nagyagite and Petzite. It occurs often dissemi- nated through pyrite and galenite in auriferous regions, rendering these minerals valuable sources of gold. Native Gold. Isometric. In octahedrons, dodecahedrons ; without cleav- age. Also in arborescent forms, consisting of strings of crystals, filiform, reticulated, in grains, thin laminae and masses. Color various shades of gold-yellow, becoming pale from alloy with silver ; occasionally nearly silver-white from the silver present. Eminently ductile and malleable. H. = 5-3. G. =12-20, varying according to the metals alloyed with the gold. Fuses at 2,016 F. (1,102 C.) 110 DESCRIPTIONS OF MIN..KALS. Composition. Native gold usually contains silver, and in very various proportions ; and the color becomes paler with the increase of silver. The finest native gold from Russia yielded gold 98-96, silver 0-16, copper 0-35, iron 0-05 ; *G. =19-099. A gold from Marmato afforded only 73-45 per cent, of gold, with 26-48 per cent, of silver; Gr.=12-666. This last is in the proportion of 3 of gold to 2 of silver. The following proportions also have been observed : 3J to 2 ; 5 to 2 ; 3 to 1 ; 4 to 1, and this the most common ; 6 to 1 is also of frequent occurrence. Average of California native gold is 88 per cent, gold, and the range mostly between 87 and 89; the range of the Canadian, mostly between 85 and 90 ; of Australian, between 90 and 96 per cent., and the average 93. The Chilian gold afforded Domeyko 84 to 96 per cent, of gold, and 15 to 3 per cent, of silver. The more argentiferous gold has been called Electrum; the atomic pro- portion of 1 : 1 between the gold and silver corresponds to 35-5 per cent, of silver, and that of 2 : 1, to 21'6 per cent. Copper is occasionally found in alloy with gold, and some- times also iron, bismuth, palladium and rhodium. A rhodium- gold from Mexico gave the specific gravity 15 '5-1 6 '8, and contained 34 to 43 per cent, of rhodium. A bismuth gold has been called Maldonite. Diff. Iron and copper pyrites are often mistaken for gold by those inexperienced in ores ; but these are brittle minerals, while gold may be cut in slices, and flattens under a hammer. Pyrite is too hard to yield at all to a knife, and copper pyrites affords a dull "greenish powder. Moreover pyrite gives off sulphur when strongly heated, while gold melts without odor. GOLD. HI Obs. Native gold is mostly confined to quartz, intersect- ing in veins, or interlaminated with, subcrystalline slaty or schistose rocks, especially hydromica and chloritic slates. It occurs sparingly iu similar or other veins in granite, gneiss, or mica slate. It has also been found in traces, according to J. J. Stevenson, in the trachytes of Colorado, and in Silurian and Carboniferous quartzytes. The quartz intersects the slaty rocks in veins and lies in thick seams between their layers. It is frequently cellular for a considerable distance from the surface owing to the alteration and removal of pyrite, galena, or other metallic ores that may be accompaniments of the gold, and the cavities are usually rusty with oxide of iron, and sometimes contain particles of sulphur left by the decomposing pyrite, and also strings or laminae of gold. The rock in this cav- ernous state is rather easily quarried out ; buc deep below, where the minerals are not removed by decomposition, mining is far more difficult. Pyrite itself is nearly as hard as quartz, when unaltered, and readily strikes fire with a steel. This pyrite is often very abundant, and contains throughout it considerable gold ; but the gold is so finely distributed, that little of it can be removed by the ordinary process of crushing and amalgamation ; nature's way consists in decomposing the pyrite and thereby making it drop its load. The galenite of a gold region is also usually auriferous. Gold sometimes occurs in the slate rocks adjoining the veins, though mostly confined to the latter. Auriferous quartz often contains no gold visible to the naked eye. But while quartz veins are to a large extent the actual repositories of the gold in its native state, a very large part of the gold derived from auriferous regions has come from the sand and gravel beds, in which it occurs in flat- tened grains, and sometimes in lumps and nuggets. By dif- ferent methods erosion by running waters, movements of glaciers, natural decomposition, and other disintegrating action the gold-bearing rocks have been extensively re- duced to earth and stones, and this loose material has been distributed along the river courses, making vast alluvial or diluvial gravelly formations. From these gravels the gold is obtained by simple washing, thus taking advantage of the high specific gravity of gold. Streams are carried in aque- ducts and thrown in great jets against the gravel bluffs to 112 DESCRIPTIONS OP MINERALS. reduce the material to loose earth and prepare it for further washing by the same water in sluices arranged for the pur- pose. The minerals most common in gold regions are platinum, iridosmine, magnetite, pyrite, galenite, ilmenite, chalco- pyrite, blende, tetradymite, zircon, rutile, barite ; also in some cases wolfram, scheelite, brookite, monazite and dia- mond. Platinum and iridosmine accompany the gold of the Urals, Brazil and California ; and diamonds are found in the gold region of Brazil, and occasionally in the Urals and United States. Gold is widely distributed over the globe. In AMERICA, it occurs in Brazil (where formerly a greater part of that used was obtained) along the chain of mountains which runs nearly parallel with the coast, especially near Villa Rica, and in the province of Minas Geraes ; in New Granada, at Antioquia, Choco and Giron ; in Chili ; sparingly in Peru and Mexico ; in Arizona ; in the Coast Range, and, much more abundantly, in the Sierra Nevada, California ; in Oregon, British Columbia and Alaska ; in New Mexico, Colorado, and Wyoming, and other parts of the Rocky Mountain region ; in the Appalachians from Virginia to Georgia, a region that formerly produced annually nearly a million of dollars ; very sparingly in Vermont, New Hamp- shire, and other New England States ; in Nova Scotia ; in Beauce County, Canada ; also, north of Lake Superior ; and in the gravel of Illinois and Indiana. In EUEOPE, it occurs sparingly in Cornwall and Devon, England ; North Wales, Scotland, and Ireland, formerly in the County of Wicklow, where a nugget of 22 ounces was found ; and in France, very sparingly in the Department of Isere ; in the sands of the Rhine, the Reuss, and the Aar ; in Tyrol and Salzburg ; on the southern slope of the Pen- nine Alps, from the Simplon and Monte Rosa to the Valley of Aosta, Northern Piedmont, where nearly G,000 ounces were obtained in 1867 ; more abundantly in Hungary, at Konigsberg, Schemnitz and Felsobanya, and in Transyl- vania, at Kapnik, Vorospatak and Offenbanya ; in Spain,, formerly worked in Asturias ; in Sweden, at Edelfors. In the Urals are valuable mines at Beresof, and other places on the eastern or Asiatic flank of this range, and the comparatively level portions of Siberia ; also in the Altai Mountains. Also in the Cailas Mountains in Little Thibet GOLD. H3 in the rivers of Syria and other parts of Asia inor ; in Ceylon, China, Japan, Formosa, Java, Sumatra, Western Borneo, the Philippines, and New Guinea. In AFRICA, at Kordofan, between Darfour and Abyssinia ; also south of Sahara, in the western part of Africa, from the Senegal to Cape Palmas ; also along the coast opposite Madagascar, between the 22d and 35th degrees south lati- tude, in the Transvaal Republic. Other regions are Tas- mania, New Zealand, and New Caledonia. General Remarks. The most productive gold regions at the present time are those of Australia and California. In Australia the richest mines are those of Victoria and New South Wales. Victoria yielded, in 1856, 3,000,000 ounces, and in 1875, 1,195,- 250 ; Australia, in 1875, 227,000 ounces. The Australian gold was first made known to the world in 1851. The localities discovered were on Summer Hill Creek and the Lewis Pond River (near lat. 33 N., long. 149-150 E.), streams which run from the northern flank of the Coriobolas down to the river Macquarie, a river flowing west- ward and northward ; it was soon afterward found on the Turon Eiver, which rises in the Blue Mountains ; and finally a region of country 1,000 miles in length, north and south, was proved to be auriferous ; the country is a region of metamorphic rocks, granite and slates, and in many parts abounds in quartz veins. Queensland and South Australia, and also Tasmania and New Zealand, afford some gold. The first discovery of gold in California was made early in the spring of 1848, on the American Fork, a tributary to the Sacramento? near the mouth of which Sutter's establishment was situated. Soon Feather River, another affluent, 18 or 20 miles north, was also proved to abound in gold about its upper portions ; and it was not long after before each stream in succession, north and south, along the western slope of the Sierra Nevada was found to flow over auriferous sands. The gold as now developed extends along that chain, through the whole length of the great north and south valley which holds the rivers and plains of the Sacramento and San Joaquin. It continues south nearly to the Tejon pass, in latitude 35, and north beyond the Shasta Mountains to the Umpqua, and less productively into Oregon and Washington Territories, and in British Columbia. Gold also occurs in some places in the coast range of mountains. Even the very site of San Francisco has been found to contain traces. North of Shasta Mountain there are important mines on the Klamath and the Umpqua, and some of the best on the sea-shore between Gold Bluff, in 41 30 south of the Klamath (30 miles south of Crescent City) to the Umpqua. What once was Rogue River is now called Gold River. In Colorado, gold mines occur in Gil pin County, and much less pro- ductively in Clear Creek, Park, Boulder, Lake, Summit, and Southern counties ; and the yield in 1874 amounted to $2,102,487, of which $1,525,447 were from Gil pin County. Nevada produced from the Comstock lode (seep. 123), in 1875, gold *o the amount of about $11, 740, 000, and the rest of Nevada, $2,25G..OOO 114 DESCRIPTIONS OF MINERALS. making in all nearly $14,000,000 ; and in 1876, the Comstock lode yielded $18,000,000, and the rest of Nevada about $1,338,000. v The yield of the United States in gold in the years 1870 to 1876, is stated as follows in a note dated February 5, 1877, by J. J. Valentine, in Jones's " Report of the Silver Commission (1877)" : 1870.. $33,750,000 1871 34,398,000 1872 38,109,395 1873 39,206,558 1874 38,466,488 1875 39,968,194 1876 42,886,935 The amount, in 1874, from California is stated at $17,620,000 ; from Oregon, $609,000 ; Washington, $155,500 ; Idaho, $1,328,430 ; Mon- tana, $2,850,000 ; Utah, $92,000 ; Arizona, $25,700 ; Colorado, $2,- 102,487 ; Mexico, $84,655 ; British Columbia, $1,636,200. According to the Report of A. del Mar, in the ' ' Report of the Sil- ver Commission of 1877," the yield of gold from all America from 1492 to the year 1800, was $1,872,300,000. From 1800 to 1847 inclu- sive, 48 years, the yield from America, Europe, and Africa is stated at $42i),200,000 ; and from 1848 to 1876 inclusive, 29 years, $3,381,500,- 000. The largest annual amount was produced in the year 1856, in which the yield was $147,600,000 ; and next to this, in 1859, with $144,900,000 ; as shown in the annexed table, giving the amounts in millions of dollars : 1848.. 1849.. 1850.. 1851 . 1852.. 1853 155-0 1854 1'3;-0 1855 135-0 1856 147-6 1857. . . .133-3 . 67-5 , 87-0 , 93-2 ,120-0 193-7 1858 , 1859 1850. 1881 18I3-3 , 1833, 1864. 1835 1836 1837. .144-6 .144-9 .119-3 .113-8 .107-8 .107-0 .113-0 .130-7 .122-2 ,114-0 1888. 1869. 1870. 1871. 187-3. 1873. 1874 1875. 1876. ..109-7 ..106-2 ..106-9 . 1070 .. 99-6 .. 97-2 .. 90-8 .. 97-5 . 90 The total amount for these years is $3,381,500,000 The following table is taken from a Report to the British House of Commons in 187( the amount for the United States only being corrected : Russia. United States. Mexico and South America. Australia. Other Countries. Total. 1850 . $16,950,000 $27,500,000 1855.. . 1860 . . 1865.. . 1870.. . 1875 . 14,200,000 15,265,000 16,135,000 22.070,000 20,000,000 73.700,000 46,000,000 53,225,000 33,750,000 40,000,000 $5,000,000 4,500,000 4,000,000 2,500,000 3,750,000 $60.325,000 52,500,000 44,100,000 29,150,000 28,750,000 $2,500,000 2.500,000 2,500,000 2,500,000 2,500,000 $155,725.000 1-20, '.65,0(10 119,960,000 89,970,000 95,000,000 GOLD. 115 Masses of gold of considerable size have been found in North Caro- lina. The largest was discovered in Cabarrus County ; it weighed 28 pounds avoirdupois (" steel-yard weight," equals 37 pounds troy), and was 8 or 9 inches long, by 4 or 5 broad, and about an inch thick. In Paraguay, pieces from 1 to 50 pounds weight were taken from a mass of rock which fell from one of the highest mountains. The largest masses of gold yet discovered have been found in aurife- rous gravel. The " Blanch Barkley Nugget," found in South Austra- lia, weighed 140 pounds, and only six ounces of it were gangue ; and one still larger, the " Welcome Nugget," from Victoria, weighed 2,195 ounces, or nearly 183 pounds, and yielded 8,376 10s. M. sterling of gold. Two others from Victoria weighed 1,021, and 1,105 ounces. In Russia, a mass was found in 1842, near Miask, weighing 90 pounds troy ; another of 27 pounds, and several of 10 pounds have been found in the Urals. The largest mass yet reported from California weighed 20 pounds. A remarkably beautiful mass, consisting of a congeries of crystals, weighing 201 ounces (value $4,000), was found in 1805, seven miles from Georgetown, in El Dorado County. The origin of gold veins, or rather of the gold in the veins, is little understood. The rocks, as has been stated, are metamorphic slates that have been crystallized by heat ; and they are the hydromica, chloritic, and argillaceous, that have been but imperfectly crystal- lized, rather than the mica schist and gneiss, which are well crystal- lized ; and the veins of quartz which contain the gold, occupy fissures through the slates, and openings among the layers, which must have been made when the metamorphic changes or crystallization took place. It was a period, for each gold region, of long-continued heat (occupying, probably, a prolonged age), and also of vast upliftings and disturbances of the beds ; for the beds are tilted at various angles, and the veins show where were the fractures of the layers, or the sep- arations and gapings of the tortured strata. The heat appears not to have been of the intensity required for the better crystallization of the more perfectly crystalline schists. The quartz veins could not have been filled from below, by injection ; they must have been filled either laterally, or from above. In all such conditions of upturning and metamorphism, the moisture present would have become intensely heated, and hence have had great dissolving and decomposing power ; it would have taken up silica with alkalies from the rocks (as happens in all Geyser regions), along with whatever other mineral substances were capable of solution or removal ; and the vapor, thus laden, would have filled all open spaces, there to make depositions of the silica and ether ingredients it contained. These mineral ingredients would have been derived either from the rock adjoining the veins or opened spaces, or from depths below through ascending vapors. By one or both of these means, the quartz must have received its gold, pyrite, and ores of lead, copper and other materials all having been carried into the open cavities at the same time with the silica or quartz. The pyrite of the vein is usually auriferous, showing that it was crystallized under the same circumstances that attended the de- positing of the gold in strings, crystals, and grains ; and the same is often true of the galena. Calavcrite is a bronze-yellow gold telluride. AuTe 4 = Tellurium LI 6 DESCRIPTIONS OF MINERALS. 55'5, gold 44-5=100, with a little silver, occurring massive at the Stan, islaus Mine, California, and the Red Cloud Mine, Colorado, and also the Keystone and Mountain Lion mines, in the Magnolia District. Krennerite is another gold telluride. Sylvanite, called also Graphic tellurium, is a telluride of gold and silver, also containing sometimes antimony and more or less lead (see p. 118). Nagyagite is a telluride of lead containing 9 to 13 per cent, of gold (see p. 149). Petzite is a telluride of silver, allied to Hessite (p. 118^, containing gold ; a specimen from Golden Rule Mine, Colorado, contained 25-60 per cent, according to Genth. II. SILVER. Silver occurs native, and alloyed, or combined with gold ; also combined with sulphur, selenium, tellurium, arsenic, antimony, bismuth, chlorine, bromine, or iodine ; but nevei as an oxide, carbonate, sulphate, or phosphate. Native Silver. Isometric. In octahedrons and other forms. No cleavage apparent. Occurs often in filiform and arborescent shapes, the threads having a crystalline character ; also in laminae, and massive. Color and streak silver-white and shining. Often black externally from tarnish. Sectile. Malleable. H. =2-5-3. G.= 10 -1-11-1. Composition. Native silver is usually an alloy of silver and copper, the latter ingredient often amounting to 10 per cent. It is also alloyed with gold, as mentioned under that metal. A bismuth silver from Copiapo, S. A., contained 16 per cent, of bismuth. B.B. fuses easily to a silver- white globule. Dissolves in nitric acid, from which it is precipitated as white chloride on adding hydrochloric acid. A clean plate of copper im- mersed in the nitric solution becomes coated with silver. Diff. Distinguished by being malleable ; from bismuth and other white native metals by affording no fumes before the blowpipe ; by affording a precipitate with hydrochloric acid which becomes black on exposure. Obs. Native silver occurs in masses and string-like ar- borescences, penetrating the gangue, or its minerals, in SILVER. 117 various silver mines. It is also found mixed with native copper. The mines of Norway, at Kongsberg, formerly afforded mag- nificent specimens of native silver, but they are now mostly under water. One specimen from this locality, at Copenha- gen, weighs five hundred pounds ; and two other masses have been found weighing 238 and 436 pounds. Other Eu- ropean localities are in Saxony, Bohemia, the Hartz, Hun- gary, Dauphiny. Peru and Mexico also alford native silver. A Mexican specimen from Batopilas, weighed when obtained 403 pounds ; and one from Southern Peru (mines of Huan- tajaya) weighed over 8 cwt. Arizona is reported to have produced one mass weighing 2,700 pounds. In the United States, in the Lake Superior region, the silver generally pen- etrates the copper in masses and strings, and is very nearly pure, notwithstanding the copper about it. Large masses occur at the Idaho Silver Mine, called the Poor Man's Lode ; and in strings it is occasionally found in the mines of Ne- vada, California, and Colorado. Much of the galena of the world contains a very small per- centage of silver ; that of Monroe, Conn., yields nearly 3 per cent. Native silver has also been observed near the Sing Sing state prison ; at the Bridgewater copper mines, N. J. ; and in handsome specimens at King's Mine, Davidson County, North Carolina. Native Amalgam is a compound of silver and mercury. The com- pounds AgHg = Silver 35*1, mercury 64'9, or Ag 2 H 3 = Silver 26'5, mercury 73 5, are included. Another from Chili having the formula Ag 12 Hgand containing 86 '6 per cent, of silver has been called AT- querite; and still another Ag ]8 Hg, Kongsbergite. Argentite. Silver Glance. Sulphuret of Silver. Isometric. In dodecahedrons more or less modified. Cleavage sometimes apparent parallel to the faces of the dodecahedron. Also reticulated and massive. Lustre metallic. Color and streak blackish lead-gray ; streak shining. Verysectile. H.= 2-2'5. G.-7-19- 7-4. Composition. When pure, Ag 2 S = Sulphur 12-9, silver 87'1. B.B. on charcoal in O.F. it intumesces, gives oif the odor of sulphur, and finally affords a globule of silver. Diff. Resembles some ores of copper and lead, and other 118 DESCRIPTIONS OF MINERALS. ores of silver, but is distinguished by being easily cut, like lead, with a knife ; and also by affording a globule of silver on charcoal, by heat alone. Its specific gravity is much higher than that of any copper ores. Obs. This important ore of silver occurs in Europe prin- cipally at Annaberg, Joachimstahl, and other mines of the Erzgebirge ; at Schemnitz, and Kremnitz, in Hungary, and at Freiberg in Saxony. It is a common ore at the Mexican silver mines, and also in the mines of South America. It occurs in Arizona, with chalcocite, at the Heintzelman Mine, and in Nevada. A mass of "sulphuret of silver" is stated by Troost to- have been found in Sparta, Tennessee. Acanthite is a trimetric sulphide of silver, Ag 2 S, from Joachimstahl ; and Daleminzite, another, from near Frei- berg. Stromeyerite. A steel-gray sulphide of silver and copper, Ag 2 S + Ciij S = Sulphur 15-7, silver 53'1, copper 31-2 = 100. G.= fr26. B.B. it fuses and gives in the open tube an odor of sulphur ; but a silver globule is not obtained except by cupellation with lead. From Peru, Silesia, Chili, Siberia, and Arizona. Sternbergite. A sulphide of silver and iron containing 33 per cent, of silver. It is a highly foliated ore resembling graphite, and like it leaving a tracing on paper ; the thin laminae are flexible ; color pinch- beck brown ; streak black. From Joachimstahl and Johanngeorgen- stadt. Naumannite. A selenide of silver and lead in iron -black cubes and massive ; G. =8 ; contains 73 per cent, of silver. From the Hartz. Hessite. A telluride of silver, Ag 2 Te= Tellurium 37-2, silver 62-8 = 100. Color between lead-gray and steel-gray. Sectile. G. =8*3 8'6. B.B. in the open tube, faint sublimate of tellurous acid; on char- coal with soda a silver globule. From the Altai ; at Nagyag and Retzbanya ; Coquimbo, Chili ; Calaveras Co. , Cal. ; Red Cloud Mine, Colorado ; Kearsarge Mine, Dry Canyon, Utah. Petzite is a hessite with the silver replaced in part by gold. G. = 8 '7-9 '4. Between steel-gray and iron -black. Variety from Golden Rule Mine, afforded Genth Tellurium 32 '68, silver 41 '86, gold 25 60= 10014. Occurs at the same localities with hessite. Tapalpite is a telluride of bismuth and silver from Mexico. Syfoanite or Graphic Tellurium, A telluride of gold and silver (Ag, Au) Tea = (if Ag : Au=l : 1) Tellurium 55 '8, gold 28'5, silver 15'7 = 100. Color and streak steel-gray to silver- white, and sometimes nearly brass-yellow. H.=l'5-2. G.=7'99-8'33. Called graphic because of a resemblance in the arrangement of the crystals to writing charac- ters. From Transylvania ; Calaveras Co. , California ; Red Cloud and Grand View Mines, Colorado. Eucairite. A selenide of silver and copper, containing 42-45 per cent, of silver ; color between silver- white and lead-gray ; easily cut by the knife. . From Sweden and Chili. SILVER. 119 Dyscrasite, or Antimonicd Silver, consists simply of silver and anti- mony (78 parts to 22=Ag 4 Sb), and has nearly a tin-white color. G. 9'4-9'8. B.B. fumes of antimony pass off, leaving finally a globule of silver. From Wolfach, Wittichen, Andreasberg ; also Allemont in Dauphiny ; and Bolivia, S. A. Pyrargyrite. Ruby Silver. Dark Red Silver Ore. Ehombohedral. ^72 = 108 42; E/^i-2 = 129 39'. Cleavage parallel to R imperfect. Also massive. Black to dark cochineal-red, with the streak cochi- neal-red and lustre splendent metallic-ada- mantine. H. = 2-2 -5, G. = 5 -7-5 -9. Composition. Ag 3 S 3 Sb (=3 Ag 2 S + Sb 3 S,) = Sulphur 17*7, antimony 22 -5, silver 59-8 = 100. B. B. fuses very easily ; on charcoal a white deposit of antimony oxide is deposited, and with soda a globule of silver is obtained. In an open tube gives off sulphurous fumes that redden litmus paper. Diff. Its red streak, and its reactions for antimony and silver, are distinctive. Obs. Occurs at Andreasberg ; also in Saxony, Hungary, Cornwall, Mexico, Chili ; in Nevada at Washoe ; abundant about Austin, Reese River ; at Poor Man's Lode, Idaho. Proustite, or Light Red Silver Ore, is a related ore con- taining arsenic in place of much or all of the antimony. Composition, Ag 3 S s As = Sulphur 19-4, arsenic 15*1, silver 65-5 = 100. G.=5-4-5-56. B. B. gives a garlic odor. Occurs with pyrargyrite at the above-mentioned localities. Stephanite. Brittle Silver Ore. Black Silver. Trimetric. 7 A 7=115 39'. No perfect cleavage. Often in compound crystals. Also massive. Streak and color iron-black. II. = 2-2 -5. G. = 6 -27. Composition. Ag 5 S 4 Sb ( = 5 Ag 2 S + Sb 2 S 3 ) = Sulphur 16-2, antimony 15*3, silver 68*5. B.B. it gives an odor of sulphur and also fumes of antimony, and yields a dark metallic globule, from which silver may be obtained by the addition of soda. Soluble in dilute nitric acid, and the solu- tion indicates the presence of silver by silvering a plate of copper. 120 DESCRIPTIONS OP MINERALS. Obs. It occurs with other silver ores at Freiberg, Schnee- berg, and Johanngeorgenstadt, in Saxony ; also in Bohe- mia, and Hungary. It is an abundant ore in Chili, Peru, and Mexico, and also in Nevada, and at the Comstock Lode, and at Ophir, and Mexican mines, in the Reese Eiver and Humboldt, and other regions ; in Colorado and Idaho. It is sometimes called black Polybasite is near stephanite in color, specific gravity, and composi- tion, but contains some arsenic and copper, with 64 to 72*2 per cent, of silver. The crystals are trimetric, and usually in tabular hexagonal prisms, without distinct cleavage. G. =6,214. From Freiberg, Przi- brarn ; Mexico and Chili; the Reese mines in Nevada, and Idaho. Miargyrite is an antimonial silver sulphide, containing but 36 '5 per cent, of silver, and having a dark cherry-red streak, though iron-black in color. B.B. on charcoal gives off fumes of antimony and an odor of sulphur ; and in the oxidating flame, a globule is left which finally yields a button of pure silver. Brongniardite occurs in regular octahedrons and massive, grayish- black in color, and contains about 25 per cent, of silver, with lead, an- timony, and sulphur G.=5'95. From Mexico. Polyargyrite also is isometric, having cubic cleavage, and is from Wolf ach in Baden. It is near polybasite in composition = 12 Ag 2 S + Sb ? S 3 . Freieslebenite is a monoclinic antimonial silver-and-lead sulphide, of a light steel-gray color, with G. =6-G'4. Contains 22 to 24 per cent, of silver. From Saxony, Transylvania, and Spain. Pyrostilpnite is another monoclinic silver ore ; its delicate crystals are grouped like stilbite and have a fire-red color. Contains 62 '3 per cent, of silver. From Freiberg, Andreasberg, and Przibram. Cerargyrite. Horn Silver. Silver Chloride. Isometric. In cubes, with no distinct cleavage. Also massive, and rarely columnar ; often incrusting. Color gray, passing into green and blue ; looks somewhat like horn or wax, and cuts like it. Lustre resinous, passing into ada- mantine. Streak shining. Translucent to nearly opaque. Composition. Ag Cl= Chlorine 24-7, silver 75-3. Fuses in the flame of a candle, and emits acrid fumes. B.B. af- fords silver easily on charcoal. The surface of a plate of iron rubbed with it is silvered. Obs. A very common ore and extensively worked in the mines of South America and Mexico, where it occurs with native silver ; and also abundant in Nevada about Austin, Lander Co. ; in Idaho at Poor Man's Lode ; occurs also in Comstock Lode ; and in Arizona ; also at the mines of Sax- ony, Siberia, Norway, the Hartz, and Cornwall. SILVER. 121 Bromyrite or Bromic Silver. Silver united with bromine. Ag Br Bromine 42 *6, silver 5 7 '4= 100. Occurs with the preceding in Mexico and Chili. Embolite. A chlorobromide of silver, resembling the chloride or horn silver. Color asparagus to olive green. Contains 51 of chloride of sil- ver, to 49 of bromide. This ore is not less common in Chili than the chloride. It has also been found in Chihuahua, Mexico. lodyrite. A silver iodide, Ag I=Iodine 54*0, silver 4G'0=100. It has a bright yellow color. From Spain, Chili, Mexico, and the Cerro Colorado Mine in Arizona. Tocornalite. A silver-and-mercury iodide from Chili. General Remarks. The chief sources of the silver of commerce ara (1) Native silver ; (2) the sulphide, Argcntite (or vitreous silver), com- mon in Mexico, and also in the Humboldt, lieese River mining dis- tricts ; four species among the sulpharsenites and sulphantimonites, viz., (3) Proustite or the light red or ruby silver ore, and (4) Pyrar- gyrite, or dark red silver ore, both common in Chilian, Peruvian, and Mexican mines ; (5) Freieslebenite ; (6) Argentiferous tetrahedrite, which contains sometimes 10 to 30 per cent, of silver, abundant at some Humboldt County, Nevada, mines, at Colorado silver mines, and at various Chilian, Bolivian and Mexican mines, as well as in some silver mines of Europe ; (7) Stephanite or brittle silver ore, common in Nevada, Colorado, and at the Washoe mines, Western Utah ; (8) the chloride, called horn-silver or Cerargyrite, common in Chili, Mexico, Idaho ; (9) the bromide and chlorobromide, Bromyrite and Embo- lite, common in Chili and Mexico, especially the latter, along with the rarer iodide ; (10) Argentiferous Galcnite, the lead ore, galenite, even when containing but 5 ounces of silver to the ton, being profita- bly worked for its silver. The other ores of silver mentioned beyond are seldom of great abundance. The most important of them are sil- ver amalgam or Arquerite, common especially in Chili, and Polybasite. Silver ores occur in rocks of various ages, in gneiss and allied rocks, in porphyry, trap, sandstone, limestone, and shales ; and the sand- stone and shales may be as recent as the Tertiary. The veins often, intersect trachytic, porphyry, and other eruptive rocks, or the sedi- mentary formations in the vicinity of such rocks, and have owed their existence in many cases to the heat, fracturing, and vapors from below, attending the eruptions. Silver ores are associated often with ores of lead, zinc, copper, co- balt, and antimony, and the usual gangue is calcite or quartz, with frequently fluor spar, pearl spar, or heavy spar. The silver of South America is derived principally from the horn silvers, stephanite, ruby silver, vitreous silver ore, and native silver. Those of Mexico are of nearly the same character. Besides, there are earthy ores called color ados, and in Peru pacos, which are mostly earthy oxide of iron, with a little disseminated silver ; they are found near the surface where the rock has undergone partial decomposition. The sulphides of lead, iron, and copper of the mining regions, gene- rally contain silver, and are also worked. In South America the Chilian mines are on the western slope of the Cordilleras, and are connected mostly with stratified deposits, of a shaly, sandstone, or conglomerate character, and their intersections 122 DESCRIPTIONS OF MINERALS. with porphyries. The chlorides and native amalgams are found in regions more toward the coast, while the sulphides and ontlmonial ores abound nearer the Cordilleras. The richest mines are not far dis- tant from Copiapo, in the mountains north of the valley of Huasco. The mines of Mt. Chanaryillo, about 16 leagues south of Copiapo, abound in horn silver, and begin to yield arsenic-sulphides at a depth of about 500 feet. The mines of Punta Brava, which are nearer the Cordilleras, afford the arsenical and antiinonial orec. In Peru, the principal mines are in the districts of Pasco, Chota, and Huantaya. Those of Pasco are 15,700 feet above the sea, while those of Huantaya are in a low desert plain, near the port of Yquique, in the southern part of Peru. The ores afforded are the same as in Chili. The mines of Huantaya are noted for the large masses of native silver they have afforded. Silver is obtained in Peru, also, in the districts of Caxamarca, Pataz, Huamanchuco, and Hualgayoc. The Potosi mines in Bolivia, occur in a mountain of argillaceous shale, whose summit is covered by a bed of argillaceous porphyry. The ore is the ruby silver, and argentite with native silver. The dis- trict of Caracoles, between Chili and Bolivia, yields much silver. In Europe the principal mines are those of Spain, the province of Guadalajara, where the ore is chiefly freieslebenite ; of Kongsberg in Norway ; of Saxony, chiefly at Freiberg ; the Hartz ; in Austria, Hun- gary, Transylvania, and the Banat ; and Russia. The mines of Kongs- berg occur in gneiss and hornblende slate, in a gangue of calc spar. They were especially rich in native silver. The mines of Saxony occur mostly in gneiss, in the vicinity of Frei- berg, Ehrenfriedensdorf, Johanngeorgenstadt, Annaberg, and Schnee- The ores of the Hartz are mostly argentiferous copper pyrites and galena, yet the ruby silver, argentite, stephanite, occur, especially at Andreaskreutz, and the mines of that vicinity. The rock intersected by the deposits is mostly an argillaceous shale. Calcitc is the usual gangue, though it is sometimes quartz. In the Tyrol, Austria, argentite, argentiferous tetrahedrite, and mis- pickel occur in a gangue of quartz, in argillaceous schist. The Hun- farian mines at Schemnitz and Kremnitz, occur in syenyte and horn- lende porphyry, in a gangue of quartz, often with calcite or barite (heavy spar), and sometimes fluorite. The ores are argentite. tetrahe- drite, galena, blende, pyritous copper and iron ; and the galena and copper ores are argentiferous. France produces some silver from ar- gent'rferous galena at Huelgoet in Brittany, and the mines of Pontgi- baud, Puy-de-Dome. The Russian mines are in Kolyvan in the Altai, and Nertchinsk in the Daouria Mountains, Siberia (east of Lake Baikal). The Daouria mines afford an argentiferous galena which is worked for its silver ; it occurs in a crystalline limestone. The silver ores of the Altai occur in Silurian schists in the vicinity of porphyry, which contain also gold, copper, and lead ores. The mines of Mexico are most abundant between 18 and 24 north latitude, on the back or sides of the Cordilleras, and especially the west side ; and the principal are those of the districts of Guanaxuato, Zacatecas, Fresnillo, Sombrerete, Catorce, Oaxaca, Pachuca, Real del Monte, Batopilas, and Tasco. The veins traverse very different rccka SILVER. 123 In these regions. The vein of Guanajuato, the most productive in Mexico, intersects argillaceous and chloritic shale, and porphyry ; it affords one-forth of all the Mexican silver. The Valeucian mine is the richest in Guanaxuato. The Pachuca, Real del Monte, and Moro districts, are near one another. Four great parallel veins tranversv these districts, through porphyry. In the United States the chief silver mines are in California, Ne- vada, Colorado, Utah, Montana, and Idaho. The principal California mines are in its southeastern counties bordering on Nevada, namely : Alpine, Mono, and Inyo ; the total yield in 1874, about $1,700 ; 000. Those of Nevada are the Washoe region, about Virginia City and the Comstock Lode ; in Lander County, along Reese River Valley, etc., the chief town of which is Austin ; Esmeralda County, southeast of Washoe ; in Eureka County, next east of Lander ; in Lincoln County, the southeastern of the State ; Huuiboldt County to the north ; White Pine, Nye and Elko counties, east and southeast of Lander County. The rocks connected with the veins in Eastern California and Western Nevada are eruptive rocks, related for the most part to andesyte (in part, named propylite) and trachyte, with some doleryte. The mines of Utah, are those of the Big and Little Cottonwood districts (which include the Emma Mine), the American Fork district, the Parley's ' Park district in the Wahsatch Range north of Big Cottonwood, and the East Tintic district, in which are the Eureka Hill mines ; those of Arizona, the Heintzelman, etc.; of Colorado, in the San Juan region; of Northern Michigan, at the copper mines ; of Canada, at Prince's Mine, Spar Island, Lake Superior. For the years previous to 1859 the whole yield of silver from United States mines is estimated at $1,000,000. The following are the amounts for the succeeding years, as published in Jones's Senate Report (1877), those for the years 1871 to 1876, inclusive, being from estimates by J. J.Valentine. 1859 $100,000 1860 150,000 1861 2,100,000 1862 4,500,000 1883 8,500,000 1864 11,000,000 18()5 11,250,000 1866... 10,000,000 1867 13,550,000 1868 $12,000,000 1869 13,000,000 1870 17,3iO,000 1871 19/286,000 1872 19,924,429 1873 27,483,302 1874 29,699,122 1875 31,635,239 1876 39,292,924 The Comstock Lode contributed to the silver of the world first in 1861. In 1875 it yielded $14,492,350, and the rest of Nevada $6,717,636^ $21,209,983 ; and in 1876 these amounts were 20,570,078 and 7,462,752 =$28,03 2,830. The $7,462,752 from the " rest of Nevada" in 1876, were divided, as follows, between its principal mining regions : Lan- der County, Austin district, $1,187,500 ; Esmeralda County, Columbus district, $1,624,789 ; Elko County, Cornucopia district, $460,048 ; Eu- reka County, $1,480,558 ; Lincoln County, Pioche or Ely district, $790,095 ; Nye County, Tyboe and Reveille districts, $1,450,000. The yield in 1876 of Utah was $3,351,5^0 ; of Colorado, 3,000,000 ; of California, 1,800,000; of Arizona, 500,000; of Montana, 800,000; of Idaho, 300,000 ; of New Mexico, 400,000. 124 DESCRIPTIONS OF MINERALS. In the " Elements of Metallurgy," of J. Arthur Phillips, the yield for 1872 is given approximately, as follows : Lbs. Troy. 52,400 15,000 92,000 Great Britain Norway and Sweden Hungary, Transylvania, and the Banat. Saxony 80,000) Haruz 27,500^ Rest of Germany 00,500) Russia France Italy Spain Peru Bolivia Chili , Central America Mexico United States. . 178,000 50,000 16,500 32,000 100,000 200,000 450,000 800,000 53,000 1,000,000 1,250,000 Total 3,788,900 Mr. Phillips states that the total for the year probably amounted to 4,100,000 Ibs. troy, the value of which is 13,000,000, or $03,000,000. In the above the amount from the United States is diminished to make it correspond with the preceding statement for 1872. The following table gives, in dollars, the estimated value of the World's production of silver in recent years : Russia. United States. Mexico and South America Other Countries. 1855 600,000 30,000,000 10,000,000-40,600,000 1800 1865 1870 1875 650,000 700,000 575,000 500,000 150,000 11,250,000 17,320,000 31,635,000 30,000,000 30,000,000 25,000,000 25,000,000 10,000,000=40,800,000 10,000,000=51,950,000 10,000,000=57,895,000 10,000,000=67,135,000 The total for 1876 is estimated at 76 millions. The world's production of silver for the period of twenty-six years, from 1852 to 1877, is estimated at $1,341,800,000 ; for the preceding twenty-two years from 1830 to 1851, inclusive at $600,400,000; for the preceding thirty years from 1800 to 1830 at $799,100,000. Native Platinum. Isometric : but crystals seldom observed. Usually in flat- tened or angular grains or irregular masses. Cleavage none. Color and streak pale or dark steel-gray. Lustre metallic, PLATINUM. 125 shining. Ductile and malleable. H.=4-4-5. G-. = 16-19; 17-108, small grains ; 17-608, a mass. Often slightly mag- netic, and some masses will take up iron filings. Composition* Platinum is usually combined with more or less of the rare metals iridium, rhodium, palladium, and osmium, besides copper and iron, which give it a darker color than belongs to the pure metal, and increase its hard- ness. A Russian specimen afforded, Platinum 78-9, iri- dium 5*0, osmium and iridium 1-9, rhodium 0-9, palladium 0-3, copper 0-7, iron 11-0=98'75. Platinum is soluble in heated aqua regia. It is one of the most infusible substances known, being wholly unaltered before the blowpipe. It is very slightly magnetic, and this quality is increased by the iron it may contain. Diff. Platinum is at once distinguished by its malleability and extreme inf visibility. Obs. Platinum was first detected in 1735 in grains in the alluvial deposits of Choco and Barbac.oa in New Granada (now U. States of Colombia), within two miles of the north- west coast of South America, where it received the name platina, derived from the word plata, meaning silver. Al- though before known, an account by Ulloa, a Spanish traveler in America in 1735, directed attention in Europe, in 1748, to the metal. It is now obtained in Novita, and at Santa Rita, and Santa Lucia, Brazil. It has been afforded most abundantly by the Urals. It occurs also on Borneo ; in the sands of the Rhine ; in those of the river Jocky, St. Domingo ; in traces in the United States, in North Carolina ; at La Francois Beaucc, Canada ; and with gold near Point Orford, on the coast of Northern California (probably de- rived, according to W. P. Blake, from serpentine rocks) ; in British Columbia. The Ural localities of Nischne Tagilsk and Goroblagodat have afforded much the larger part of the platinum of com- merce. It occurs, as elsewhere, in alluvial beds ; but the courses of platiniferous alluvium have been traced to a great extent up Mount La Marti ane, which consists of crystalline rocks, and is the origin of the detritus. One to three pounds are procured from 3,700 pounds of sand. Though commonly in small grains, masses of considerable size have occasionally been found. A mass weighing 1,088 grains was brought by Humboldt from South America and deposited in the Berlin Museum. Its specific gravity was 126 DESCRIPTIONS OP MINERALS. 18-94. In the year 1822, a mass from Condoto was de- posited in the Madrid Museum, measuring 2 inches and 4 lines in diameter, and weighing 11,641 grains. A more remarkable specimen was found in the year 1827 in the Urals, not far from the Demidoff mines, which weighed 11 (more accurately, 11-57) pounds troy; and similar masses are now not uncommon. The largest yet discovered weighed 21 pounds troy ; it is in the Demidoff cabinet. Russia affords annually about 35 cwt. of platinum, which is about five times the amount from Brazil, Borneo, Colom- bia, and St. Domingo. Borneo affords about 500 pounds per year. The North Carolina platinum was found with gold in Rutherford County. It was a single reniform granule, weigh- ing 2*54 grains. Other instances are reported from the Southern gold region. The infusibility of platinum and its resistance to the action of the air, and moisture, and most chemical agents, renders it of great value for the construction of chemical and philosophical apparatus. The large stills employed in the concentration of sulphuric acid are now made of plati- num ; but such stills are gilt within, since platinum when unprotected is acted upon by the acid, and soon becomes porous. It is also used for crucibles and capsules in chemi- cal anal} r sis ; for galvanic batteries ; as foil, or worked into cups or forceps, for supporting objects before the blowpipe. It alloys readily when heated with iron, lead, and several of the metals, and is also attacked by caustic potash and phos- phoric acid, in contact with carbon ; and consequently there should be caution when heating it not to expose it to these agents. It is employed for coating copper and brass ; also for painting porcelain and giving it a steel lustre, formerly highly prized. It admits of being drawn into wire of ex- treme tenuity. Platinum was formally coined in Russia. The coins had the value of 11 and 22 rubles each. This metal fuses readily before the "compound blow- pipe ; " and Dr. Hare succeeded in 1837 in melting twenty- eight ounces into one mass. The metal was almost as malle- able and as good for working as that obtained by the other process; it had a specific gravity of 19-8. He afterwards succeeded in obtaining from the ore masses which were 90 PALLADIUM. 127 per cent, platinum, and as malleable as the metal in ordi- nary use, though somewhat more liable to tarnish, owing to some of its impurities. Deville and Debray have perfected this process, and have melted over 25 pounds of platinum in less than three-quarters of an hour. In the process the osmium present is oxidized and thus removed. Platin-iridium. Grains of iridium have been obtained at Nischne Tagilsk, consisting of 76 '8 iridium, and 19 '64 platinum, with some palladium and copper. A similar platin-iridium has been obtained at Ava, in the East Indies. Another, from Brazil, contained 27 '8 iridium, 55 '5 platinum, and 6 '9 of rhodium. Iridosmine. A compound of iridium and osmium from the platinum mines of Eussia, South America, the East Indies, and California. The crystals are pale steel-gray hexagonal prisms ; usually in flat grains. H. = 6 -7. G. = 19 -5-21 1. Malleable with difficulty. The composition varies. One variety, called Newjanskite, contains iridium 40 '8, osmium 493, rhodium 32, iron 0'7. Another, Sisser- skite, iridium 25*1, osmium 74*9, and iridium 20, osmium 80. But analysis affords also from 0'5 to 12 3 of rhodium, and 02 to 6 '4 of the rarer metal ruthenium, with traces usually of platinum, cop- per and iron. The grains are distinguished by their superior hardness from those of platinum, and also by the peculiar odor of osmium when heated with nitre. Iridosmine is common with the gold of Northern California, and injures its quality for jewelry. Occurs sparingly in the gold washings on the rivers Du Loup and Des Plantes, Canada. The metal iridium is extremely hard, and is used, as well as rho- dium, for points to the nibs of gold pens. Its specific gravity is 21 '8. Laurite. In minute octahedrons. A ruthenium sulphide, with 3 per cent, of osmium. From platinum sands of Borneo and Oregon. Palladium. Isometric. In minute octahedrons. Occurs mostly in grains, sometimes composed of divergent fibres. Color steel-gray, inclining to silver- white. Ductile and malleable. H. 4-5-5. G. =11 -3-12 -2. Consists of palladium, with some platinum and iridium. Fuses with sulphur, but not alone. Obs. Occurs in Brazil with gold, and is distinguished from platinum, with which it is associated, by the divergent structure of its grains. It was discovered by Wollaston, in 1803. Selenpalladite, or Allopalladium, is native palladium in hexagonal tables from Tilkerode in the Hartz. It is re- ported also from St. Domingo and the Urals. Porpezile is palladium gold, or gold containing about 10 per cent, of palladium ; three samples assayed at the Eio de Janeiro mint yielding 11-1, 9 -75, and 7 '7 per cent, of palladium. 128 DESCRIPTIONS OF MINERALS. This metal is malleable, and when polished has a whitish steel-like lustre which does not tarnish. A cup weighing 3J pounds was made by M. Breant in^the mint at Paris, and is now in the garde-meuble of the French crown. In hard- ness it is equal to fine steel. 1 part fused with 6 of gold forms a white alloy ; and this compound was employed, at the suggestion of Dr. W^llaston, for the graduated part of the mural circle constructed by Trough ton for the Eoyal Observatory at Greenwich. Palladium has been employed also for certain surgical instruments. MERCURY. Mercury occurs native ; alloyed with silver forming na- tive amalgam ; and in combination with sulphur, selenium, chlorine, or iodine, and with sulphur and antimony in some tetrahedrite. Its ores are completely volatile, excepting when silver or copper is present. Native Mercury. Isometric. Occurs in fluid globules scattered through the gangue. Color tin-white. G. 13-56. Becomes solid and crystallizes at a temperature of 39 F. Mercury, or quicksilver, as it is often called (a translation of the old name "argentum vivum)," is entirely volatile before the blowpipe, and dissolves readily in nitric acid. Obs. Native mercury is a rare mineral, yet is met with at^the different mines of this metal, at Almaden in Spain, Idria in Carniola (Austria), in Hungary, Peru, and in Cali- fornia. It is usually in disseminated globules, but is some- times accumulated in cavities so as to be dipped up in pails. Mercury is used for the extraction of gold and silver ores. It is also employed for silvering mirrors, for thermometers and barometers, and for various purposes connected with medicine and the arts. Native Amalgam. See page 117. Cinnabar. Mercury Sulphide. Rhombohedral. R^R=12 3G'. Cleavage lateral, high- ly perfect. Crystals often tabular, or six-sided prisms. Also massive ; sometimes in earthy coatings. SILVER. 129 Lustre unmetallic, of crystals adamantine ; often dull. Color bright red to brownish red, and brownish black. Streak scarlet-red. Sub transparent to nearly opaque. H. = 2-2-5. G.= 8-5-9. Sectile. Composition. Hg S 2 = Sulphur 13-8, mercury 86-2. It often contains impurities. The liver ore, or hepatic cinna- bar, contains some carbon and clay, and has a brownish streak and color. The pure variety volatilizes entirely be- fore the blowpipe. Diff. Distinguished from red oxide of iron and chromate of lead by vaporizing before the blowpipe ; from realgar by giving off on charcoal no alliaceous fumes. Obs. Cinnabar is the ore from which the principal part of the mercury of commerce is obtained. It is when pure identical with the pigment vermilion. It occurs mostly in connection with siliceous, talcose and argillaceous slates, or other stratified deposits, both the most ancient and those of more recent date. The mineral is too volatile to be expected in any abundance in proper igneous or crystalline rocks, yet has been found sparingly in granite. The localities are mentioned beyond. Metacinnabarite is the same compound with cinnabar, but differs in crystallization ; it is from Redington Mine, Lake County, California. Guadalcazarite, of Mexico, is Hg S in which a little of the sulphur is replaced by selenium. Calomel or Horn Quicksilver. A tough, sectile mercury chloride, of a light yellowish or grayish color, and adamantine lustre, translucent or subtranslucent, crystallizing in secondaries to a square prism. H.=l-2. G.=6'48. It contains 151 per cent, of chlorine, and 84 '9 of mercury. lodic Mercury. . A reddish-brown ore, from Mexico. Tiemannite. A dark steel-gray mercury selenide, from the Hartz, and the vicinity of Clear Lake, California. Coloradoite. A grayish black mercury telluride, with G.=8'627, from the Keystone and Mountain Lion Mines, Colorado. (Genth.) Magnolite. A mercurous tellurate, Hg Te, from Magnolia dis* trict, Colorado. General Remarks. Tlie following are the regions of the principal mines of mercury. At Idria, in Austria (discovered in 1407), where the ore is a dark bituminous cinnabar distributed through a blackish shale or slate, containing some native mercury ; at Almaden, in Spain, near the frontier of Estremadura, in the province of La Mancha, in argillaceous beds and grit rock, which are intersected by dikes of " black porphyry " and granite mines mentioned by Pliny as afford- ing vermilion to the Greeks, 700 years before the Christian era ; in the Palatinate on the Rhine ; in Hungary; Sweden ; several points in France ; Ripa, in Tuscany ; in Shensi, in China ; at Arqueros, % 130 DESCRIPTIONS OF MINERALS. Chili , at Huanca Yelica and some other points in Peru ; at St. Onofre and other places in Mexico ; in California and Idaho. The most noted of the California mines, New Almaden, is situated in Mine Hill, Santa Clara County, south of San Francisco. The rocks are altered Cretaceous slates, talcose in part, with beds of serpentine either side, and associated also with beds of jasper or siliceous slate. The New Idria mine is in Fresno County, in the Mt. Diablo Range, and was discovered in 1855. The rocks are more or less altered silico- argillaceous and siliceous slates and sandstones, and the cinnabar is distributed irregularly through them ; between this and the Aurora Mine on San Carlos (the highest peak of the Diablo Range, 4,977 feet), there is much serpentine (in which is chromic iron) and siliceous rock or slate. In Napa Valley, Napa County, north of San Francisco, there are other valuable mines situated in rocks closely similar, as Whitney states, to those affording quicksilver at New Almaden. They are in a serpentine belt, the cinnabar being in some places in the serpentine, but mostly in the peculiar siliceous rock associated with it. Native mercury occurs with the cinnabar. The product of the California mines of mercury in 1874, is given as follows by Raymond, in his " Mineral Resources for 1875" : New Almaden Santa Clara County 9, 084 flasks. New Idria Fresno Cerro Bonito " California Napa Manhattan. . Phoenix Washington. Redington Lake California Borax. Great Western . . Buckeye Colusa Missouri Sonoma Oakland ' ' Saint John. . ..Solano .7,000 900 ,3,000 , 620 , 685 . 200 .7,200 , 570 1,900 , 700 , 200 307 1,900 Which, with the additions from a few other less productive open- ings, make a total of 34,254 flasks, or over 2,400,000 Ibs. The yield in 1867 was 44,386 flasks, or about 3,400,000 Ibs. The total yield of the world in 1872, is stated by Phillips at 6,670,000 Ibs. avoirdupois. COPPER. Copper occurs native in considerable quantities ; and also combined with oxygen, sulphur, selenium, arsenic, anti- mony, chlorine, and as carbonate, phosphate, arsenate, sul- phate, and vanadate. The ores of copper vary in specific gravity from 3-5 to 8-5, and seldom exceed 4 in hardness. ORES OF COPPER. 13^ Native Copper. Isometric. In octahedrons ; no cleavage apparent. Often in plates or masses, or arborescent and filiform shapes. Color copper-red. Ductile and malleable. H. =2*5-3. G.=8-84. Native copper often contains a little silver disseminated throughout it. Before the blowpipe it fuses readily, and on cooling it is covered with a black oxyd. Dissolves "in nitric acid, and produces a deep azure-blue solution on the addition of ammonia. Obs. Native copper accompanies the ores of copper, and usually occurs in the vicinity of dikes of igneous rocks. Siberia, Cornwall, and Brazil are noted for the native cop- per they have produced. A mass, supposed to be from Bahia, now at Lisbon, weighs 2,616 pounds. South of Lake Supe- rior about Portage Lake on Keweenaw Point, and also, less abundantly, on the Ontanagon Eiver, and at some other points in that region, native copper occurs mostly in veins in trap, and also in the enclosing sandstone. A mass weighing 3,704 Ibs. has been taken from thence to Wash- ington City ; it is the same that was figured hy School- craft, in the American Journal of Science, volume iii., p. 201. One large mass was quarried out in the '' Cliff Mine," whose weight has been estimated at 200 tons. It was 40 feet long, 6 feet deep, and averaged 6 inches in thickness. This copper contains, intimately mixed with it, about y\ per cent, of silver. Besides this, perfectly pure silver, in strings, masses, and grains, is often disseminated through the cop- per, and some masses, when polished, appear sprinkled with large white spots of silver, resembling, as Dr. Jackson ob- serves, a porphyry with its feldspar crystals. Crystals of native copper are also found penetrating masses of prehnite and analcite in the trap rock. This mixture of copper and silver cannot be imitated by art, as the two metals form an alloy when melted together. It is probable that the separa- tion in the rocks is due to the cooling from fusion being so extremely gradual as to allow the two metals to solidify separately, at their respective temperatures of solidification the trap being an igneous rock, and ages often elapsing, as is well known, during the cooling of a bed of lava, covered from the air. Native copper occurs sparingly in St. Ignace and Michipicoton Islands, Lake Superior. 132 DESCRIPTIONS OF MINERALS. Small specimens of native copper hare been found in the States of New Jersey, Connecticut, and Massachusetts, where the Triassic formation occurs. One mass from near Somer- yille, N. J., weighs 78 pounds, and is said originally to have weighed 128 pounds. Within a few miles to the north of New Haven, Conn., one mass of 90 pounds, and another of 200, besides other smaller, have been found in the drift, all of which came from veins in the trap or associated Triassic sandstone. Near New Brunswick, N. J., a vein or sheet of copper, from a sixteenth to an eighth of an inch thick, has been observed and traced along for several rods. Native copper occurs also in South Australia ; it is stated that a single train from the Moonta Mine carried away at one time forty tons of native copper. Chalcocite. Copper Glance. Vitreous Copper Ore. Redrutliite. Trimetric. /: 7=119 35', Cleavage parallel to /, but indistinct. Also in com- pound crystals like aragonite. Often mas- sive. Color and streak blackish lead-gray ; often tarnished blue or green. Streak sometimes shining. H.=2'5-3. G. =5-5-5 -8. Composition. Cu 2 S Sulphur 20-2, cop- per 79-8=100. B.B. on charcoal gives off fumes of sulphur, fuses easily in the exte- rior flame ; and after the sulphur is driven off, a globule of copper remains. Dissolves in heated nitric acid, with a precipitation of the sulphur. Diff. Resembles argentite, but it is not sectile, like that ore, and they afford different results before the blowpipe. The solution of the ore in nitric acid covers an iron plate (or knife blade) with copper, while a similar solution of the silver ore covers a copper plate with silver. Obs. Occurs with other copper ores in beds and veins. At Cornwall, splendid crystallizations occur. Siberia, Hesse, Saxony, the Banat, Chili, etc., afford this ore. In the United States, a vein affording fine crystallizations occurs at Bristol, Conn. Other localities are at Wolcott- ville, Simsbury, and Cheshire, Conn. ; at Schuyler's Mines, and elsewhere, N. J. ; in the U. S. copper-mine district, Blue Eidge, Orange County, Virginia; between New Market and Taneytown, Maryland ; and sparingly at the copper ORES OF COPPER. 133 mines of Michigan and the Western States; also at some mines north of Lake Huron ; in the San Juan mining region, Colorado ; north of Gila Riva, near the borders of New Mexico and Arizona ; at the Bruce Mines, Lake Huron, and at Prince's Mine, Spar Island, and on Michipicoton Islands, Lake Superior. Covellite, or Blue Copper. A dull blue-black massive mineral, with the composition CuS. G=3'8. It contains 66*5 per cent, of copper. Harrisite. A copper glance with cubic cleavage, from Canton Mine, Ga. ; probably a pseudomorph after galenite. Chalcopyrite. Copper Pyrites. Copper-and-Iron Sulphide. Dimetric. Crystals tetrahedral or octahedral ; sometimes compound. / A 7=109 53', and 108 40'. Cleav- age indistinct. Also massive, and of various imitative shapes. Color brass-yellow, often tarnished deep yellow, and also iridescent. Streak unmetallic, greenish black, and but little shining. H.=3'5-4. G. =4-15-4-3. Composition. CuFe S 2 = Sulphur 34-9, copper 34-6, iron 30-5 = 100. Fuses B.B. to a globule which is magnetic, owing to the iron present. Gives sulphur fumes on charcoal. With soda on charcoal affords a glo- bule of metallic iron with copper. The usual effect with nitric acid. Diff. This ore resembles native gold, and also pyrite. It is distinguished from gold by crumbling when it is attempted to cut it, kistead of separating in slices ; and from pyrite in its deeper yellow color, and in yielding easily to the point of a knife, instead of striking fire with a steel. Obs. Copper pyrites occurs in veins intersecting gneiss and other rnetamorphic rocks ; also in those connected with eruptive rocks ; and sometimes in cavities or veins in ordi- nary stratified rocks. It is usually associated with pyrite, and often with galenite, blende, and copper carbonates. The copper of Fahlun, Sweden, is obtained mostly from this ore, where it occurs with serpentine in gneiss. Other mines of this ore are in the Hartz, near Goslar ; in the Banat, Hun- gary, Thuringia, etc. The Cornwall ore is mostly of this kind. As prepared for sale at Kedruth it rarely yields 12 134 DESCRIPTIONS OP MINERALS. per cent., and generally only 7 or 8, and occasionally as little as 3 to 4 per cent, of metal ; "6J per cent, of metal may be considered an average of the produce of the total quantity of ore sold." (Phillips, 1874.) Such poverty of ore is only made up by its facility of transport, the moderate expense of fuel, or the convenience of smelting. Its richness may generally be judged of from the color: if of a fine yellow hue, and yielding readily to the hammer, it is a good ore ; but if hard and pale yellow it contains much pyrite, and is of poor quality. In the United States there are many localities of this ore. It occurs in mines in Vermont, at Strafford ; and at Shrews- bury, Corinth, Waterbury ; also in New Hampshire, Maine, Massachusetts, and Connecticut; in New York, at the Ancram lead mine ; also near Eossie, and at Wurtzboro' ; in Penn- sylvania, at Morgantown ; in Virginia, at the Phenix copper mines, Fauquier County, and at the Walton gold mine, Luzerne County; in Maryland, in the vicinity of Liberty and New London in Frederick County; and at the Patapsco mines near Sykesville ; in North Carolina, in Davidson and Guilford counties. In Michigan, where native copper is so abundant, this is a rare ore ; but it occurs at Presqu'isle, at Mineral Point, and in Wisconsin, where it is the predomi- nating ore ; in Tennessee, in Polk County, at the Iliwassee mines ; in the San Juan mining region, Colorado ; in Lan- der Co., and elsewhere, Nevada ; at Copperopolis, Calaveras Co., California ; also at the Bruce and other mines on Lake Huron ; and Michipicoton Islands, in Lake Superior. Cubanite is a copper-and-iron sulphide, containing Sulphur 39 '0, iron 38'0, copper 19 '8, silica 2'3=99'12. Bornite. Erubescite. Variegated Copper Pyrites. Isometric. Cleavage octahedral in traces. Occurs in oc- tahedrons and dodecahedrons. Also massive. Color between copper-red and pinchbeck-brown. Tar- nishes rapidly on exposure. Streak pale grayish-black and but slightly shining. Brittle. H. = 3. G. = 5. Composition. Cu 3 Fe S 3 = Sulphur 28-6, copper 55 -58, iron 16-36 ; but varies much. The ore of Bristol, Conn., afforded Sulphur '25 '83, copper 61-79, iron 11-77=99-39. B.B. on charcoal fuses to a brittle globule attractable by ORES OF COPPER. 135 the magnet ; dissolves in nitric acid, with separation of sulphur. I) iff. This ore is distinguished from the preceding by its pale reddish-yellow color, and its rapidly tarnishing and becoming of bluish and reddish shades of color, the quality to which the name erubescite, from the Latin word for to blush, alludes. Obs. Occurs, with other copper ores, in granitic and al- lied rocks, and also in stratified formations. The mines of Cornwall have afforded crystallized specimens, and it is there called, from its color, " horse-flesh ore." Other foreign localities of massive varieties are Ross Island, Killarney, Ire- laud ; Norway, Hessia, Silesia, Siberia, and the Banat. Fine crystallizations were formerly obtained at the Bristol copper mine, Conn., in granite; and also in red sandstone, at Cheshire, in the same State, with malachite and barite. Massive varieties occur at the New Jersey mines, and in Pennsylvania. Orookesite. A copper selenide, containing 17 '25 per cent, of thallium, and a little silver. Domeykite, Alyodonite and Whitneyite are copper arsenides ; Ber- zelianite, a copper selenide ; Eucairite, a copper-and-silver selenide. Tennantite. A compound of copper, iron, sulphur, and arsenic. It occurs in dodecahedral crystals, brilliant, with, a dark lead-gray color, and reddish-gray streak. From the Cornish mines near Redruth and St. Day in Cornwall. Tetrahedrite. Gray Copper. Fahlerz. Isometric and tetrahedral. Occurs in tetrahedral forms. Cleavage octahedral in traces. Color between steel-gray and iron- black. Streak nearly like the color, sometimes inclined to b"own and cherry-red. Rather brittle. H.=3- 4-5. G. =4-5- 5-12. Composition. Cu s S 7 Sb 2 ( = 4 Cu 2 S + Sb 8 S 3 ), but with part of the cop- per replaced usually by iron and zinc, and sometimes silver or quick- silver, and part of the antimony by arsenic, and rarely bismuth. It 'sometimes contains 30 per cent, of silver in place of part of the copper, and is then called argentiferous tetrahedrite. The amount of arsenic varies from to 10 per cent. One variety from Spain in- cluded 10 per cent, of platinum, and another from Hohen' 136 DESCRIPTIONS OF MINERALS. stein some gold. Specimens from Schwatz, and some oilier localities, contain 15 to 18 per cent, of mercury, and are called ^/Huiio/i/c. A kind containing !) (<> i:> percent, of lead and 10 to 13 of silver, has been called MalinotrHkilc. Obs. The Cornish mines, Andnwibefg in the llariz, Krcinnit?: in Hungary, Freiberg in Saxony, KapniU in Tran- sylvania, and Dillenberg in Nassau, alTord line crysialliza- tions of this ore. It is a common ore in the Chilian mines, and it is worked there and elsewhere for copper and often also for silver. Occurs also in Mexico ; in Mariposa, and Shasta counties, Cal. ; abundantly at the Sheba and De Soto mines, Ilumboldt Co.; Nevada, near Austin in Lander Co. ; in the San Juan region, Colorado; at the lleint/elman Mine, and the Santa Rita Mine, in Ari/ona ; also in line crystallizations in the caves of Huallanea, on the Peruvian Andes, at a height of about 14,700 feet, an ore yielding much silver. Bournonite, Contains Sulphur 29'f>, antimony 05-0, load 42*24, cop- per 18*0 100. Its crystals arc modified rectangular prisms, of a steel- gray color and streak, and arc often compounded into shapes like a cog- wheel, \\hence it is called trlu'.l-orc. 11. =2 '5-3. G. 5-700. Prom the Tyrol, Hart/, Transylvania, Saxony, Cornwall, and Siberia. Other sulphautiiuonites or sulpharsenites of copper are (/m/cdftihitc, Empl(t'tit<\ Itinnitc, Stylotypite, AiktHid', timiryit^, Polybasitc. 1'oly- basitc contains also silver. Atacamite. Copper Oxichloride. Trimetrio ; in rhombic prisms and other forms ; also granular massive. Color green to blackish green. Lustre adamantine to vitreous. Streak apple-irreen. Translucent to subtranslucent. II. = 3-3-5. G. = 3-75-3-9. Com- position, Cu Clj + 3 Cu O a H 8 = Chlorine 1(1 (!, oxygen 11 '25, copper 11*25, water 12-G6 = iOO. From the Atacama ilesert, hdween Chili and IVru. and clewhcre in Chili; also from Bolivia, Vesuvius, Saxony, Spain, Cornwall. ' Cuprite. Red Copper Ore. Isometric. In regular octahedrons, and modified forms of the same. Cleavage octahedral. Also massive, and some- times earthy. Color dce v p red, of various shades. Streak brownish red. Lustre adamantine or submetallic ; also earthy. Subtrans- parent to nearly opaque. Brittle. H. = 3'5-4. G. =5*85- C-15. ORES OF COPPER. 137 Civ, = Oxygen 11*2, copper 88'8. B.B. on charcoal, yields a globule of copper. Dissolves in nitric acid. The earthy varieties have been called tile ore, from the color. 8. Diff. From cinnabar it differs in not being volatile before the blowpipe ; and from red iron ore in yielding a bead of copper on charcoal, and copper reactions. Obs. Occurs with other copper ores in the Banat, Thu- ringia, Cornwall, at Chessy near Lyons, in Siberia, and Bra- zil. The octahedrons are often green, from a coating of malachite. In the United States, it has been observed crystallized and massive at Schuyler's, Somerville, and the Flemington cop- per mines, N. J. ; also near New Brunswick, N. J. ; at Bristol, Conn.; near Ladenton, Rockland County, N. Y.; in the Lake Superior region. Tenorite, Melaconite, or Black Copper. An oxide of cop- per, CuO, occurring as a black powder, and in dull black masses and botryoidal concretions, in veins or along with other copper ores ; also in iron-gray flexible scales, in the Vesuvian lavas. It is an abundant ore in some of the cop- per mines of the Mississippi Valley, and yields GO to 70 per cent, of copper. It results from the decomposition of the sulphides and other ores. At the Hiwassee Mine, Polk Co., Tennessee, it has been abundant. It was formerly found of excellent quality in the Lake Superior copper region. Chalcanthite. Blue Vitriol. Sulphate of Copper. Triclinic. In oblique rhomboidal prisms. Also as an efllorescence or incrustation, and stalactitic. Color deep sky-blue. Streak uncolored. Subtransparcnt to translucent. Lustre vitreous. Soluble, taste nauseous and metallic. H.=2-2'5. G.=2-21. 138 DESCRIPTIONS OF MINERALS. Composition. Cu O t S + 5 aq= Sulphuric acid (or sulphur trioxide) 32'1, copper oxide 31*8, water 36*1. A polished plate of iron in solutions becomes covered with copper. Obs. Occurs with the sulphides of copper as a result of their decomposition, and is often in solution in the waters flowing from copper mines. Occurs in the Hartz, at Fahlui\ in Sweden, and in many other foreign copper regions ; in,( the Hiwassee copper mine, Tennessee ; the Canton mine, Georgia ; at Copiapo, Chili. Blue vitriol is much used in dyeing operations and in the printing of cotton and linen ; also for various other pur- poses in the arts. It has been employed to prevent dry rot, by steeping wood in its solution : and it is a powerful pre- servative of animal substances ; when imbued with it and dried, they remain unaltered. It is afforded by the decom- position of copper pyrites, in the same manner as green vit- riol from iron pyrites ; but it is manufactured for the arts, chiefly from old sheathing-copper, copper turnings, and cop- per refinery scales. In Frederick County, Maryland, blue vitriol is made from a black earth which is an impure oxide of copper with cop- per pyrites. In some mines, the solution of sulphate of copper is so abundant as to afford considerable copper, which is obtained by immersing clean iron in it, and is called copper of cemen- tation. At the copper springs of Wicklow, Ireland, about 500 tons of iron were laid at one time in the pits ; in about 12 months the bars were dissolved, and every ton of iron yielded a ton and a half, and sometimes nearly two tons, of a precipitated reddish mud, each ton of which produced 16 cwt. of pure copper. The Eio Tinto Mine in Spain is an- other instance of working the sulphate in solution. These waters yield annually 1,800 cwt. of copper, and consume 2,400 cwt. of iron. Brochantite. An insoluble copper sulphate, containing 17 '7 per cent, of sulphur trioxide. Color emerald-green. In tabular rhombic crystals, from the Urals, Retzbanya, Cornwall, Mexico, Chili, Aus- tralia. Krisumgtie and Konigite are the same species. Langite, CyanotricMte (Velvet copper ore), Kronkite, Philippite, Enysite, Linarite, Dolerophanite, Hydrocyanitc, are other sulphates containing copper, the last two anhydrous ; and Gonnellite is another containing chlorine, from Cornwall. The Copper tungstate, Cuprotungstite, occurs of a yellowish-green color in Chili. g b ORES OF COPPER. 139 Olivenite. Hydrous Copper Arsenate. Trimetric. /A/ 92 30'. In prismatic crystals, and also fibrous and granular massive . Olive-green, and of other greenish shades, to liver and wood-brown. Streak olive-green to brown. Substransparent to opaque. Brittle. H. = 3. G.=4-l-4-4. Composition. Cu 4 9 As 2 = Arsenic pentoxide 40-66, copper oxide 56-15, water 3 ; 19 = 100. Fuses very easily, coloring the flame bluish green. B.B. fuses with deflagration, giv- ing off arsenical fumes, and affords a brittle globule, which with soda yields metallic copper. Obs. From Cornwall, the Tyrol, Siberia, Chili, and other places. Besides the above, there are the following salts of copper : Copper Arsenate*. Euchroite has a bright emerald -green color, and contains 33 per cent, of arsenic acid, and 48 of oxide of copper ; occurs in modified rhombic prisms ; H.=8*75 ; G=8*4 ; from Libethen, in Hun- ary. Clinoclasite (Aphancsite] is of a dark verdigris-green inclining to lue, and also dark blue; H. =25-3; G. =4 19-4 '3(3. It contains 62'7 per cent, of copper oxide ; from Cornwall. Erinite has an emerald-green color, and occurs in mammillated coatings ; H.=4'5-5 ; G.=4'04; con- tains 59 '4 per cent, of copper oxide ; from Limerick, Ireland. Liroco- nite varies from sky-blue to verdigris-green ; occurs in rhombic prisms, sometimes an inch broad ; H.=2-2'5; G.=2-8-2'98. Chalcophylliti (copper mica} is remarkable for its thin foliated or mica-like structure color emerald or grass-green ; H. =2 ; G. =2 '55. Contains 58 per cent. of copper oxide ; from Cornwall and Hungary. Tyrolite (Copper froth) is another arsenate of a pale apple-green and verdigris-green color ; it has a perfect cleavage ; it contains 43 9 per cent, of copper oxide ; from Hungary, Siberia, the Tyrol, and Derbyshire. Cormcatt- iU and Cldorotile, are names of other copper arsenates. These dif- ferent arsenates of copper give an alliaceous odor when heated on charcoal before the blowpipe. Copper Phosphates. Pseudomalachite (Phospliochalcite, Ehlite, Dt Ttydrite) occurs in very oblique crystals, or massive and incrusting, and has an emerald or blackish-green color; H. =45-5 ; G. =4'34 ; contains 64 to 70 per cent, of copper oxide ; from near Bonn, on the Rhine, and also from Hungary. Libethenite has a dark or olive-green color, and occurs in crystals, usually octahedral in aspect, and massive ; H. = 4; G.=3'6-8-8; contains 66 '5 per cent, of oxide of copper; from Hungary and Cornwall. Other copper phosphates are Veszelyite, Tagilite, Isoclasite. Torbernite is a copper-and-uranium phosphate. These phosphates give no fumes before the blowpipe, and have the reaction of phosphoric acid. Copper Vanadates. Volborthite is a copper-and- calcium vanadate from the Urals ; and Mottrammite and Psittacinite, copper-and-lead vanadates, the former from England, and the latter from gold mines in Silver Star district, Montana. Riwtite. Yellowish-green copper antimonate and carbonate. 140 DESCKIPTIONS OP MINERALS. Malachite. Green Copper Carbonate. Monoclinic. Usual in incrustations, with a smooth tube- rose, botryoidal, or stalactitic surface ; structure finely and firmly fibrous. Also earthy. Color light green, streak paler. Usually nearly opaque ; crystals translucent. Lustre of crystals adamantine inclin- ing to vitreous ; but fibrous incrustations silky on a cross fracture. Earthy varieties dull. H.=3'5-4. G.=3'7-4. Composition. Cu 2 4 C + H 2 = Carbon dioxide (or car- bonic acid) 19-9, copper oxide 71*9, water 8*2=100. Dis- solves with effervescence in nitric acid. B.B. decrepitates and blackens, colors the flame green, and becomes partly a black scoria. AVith borax it fuses to a deep-green globule, and ultimately affords a bead of copper. Diff. Eeadily distinguished by its copper-green color and its associations with copper ores. It resembles a siliceous ore of copper, chrysocolla, a common ore in the mines of the Mississippi Valley; hut it is distinguished by its complete so- lution and effervescence in nitric acid. The color also is not the bluish green of chrysocolla. Obs. Green malachite usually accompanies other ores of copper, and forms incrustations, which, when thick, have the colors banded and delicate in their shades and blending. Perfect crystals are quite rare. The mines of Siberia, at Nischne Tagilsk, have afforded great quantities of this ore. A mass, partly disclosed, measured at top 9 feet by 18 ; and the portion uncovered contained at least half a million pounds of pure malachite. Other noted foreign localities are Chessy, in France; Sandlodge, in Shetland; Schwatz in the Tyrol ; Cornwall ; the Island of Cuba ; Serro do Bembe, west coast of Africa ; copper mines of Australia ; Chili. The copper mine of Cheshire, Conn., has afforded hand- some specimens ; also Morgantown, Perkiomen, and Phoenix- ville, Penn. ; Schuyler's Mine, and the New Brunswick copper mine, N. J. ; it occurs also in Maryland, between Newmarket and Taneytown ; and in the Catoctin Mountains ; in the Blue Kidge, Penn., near Nicholson's Gap ; also in ntic district, Utah. TiAt Mineral Point, Wisconsin, a bluish silico-carbonate of ocpper occurs, which is for the most part chrysocolla, or a mixture of this mineral with the carbonate. ORES OF COPPER. 141 This mineral receives a high polish and is used for tables, mantelpieces, vases ; and also ear-rings, snuff-boxes, and va- rious ornamental articles. It is not much prized in jewelry. At Versailles there is a room furnished with tables, vases, and other articles of this kind ; and similar rooms are to be found in many European palaces. Malachite is sometimes passed off in jewelry as turquois, though easily distinguished by its shade of color and much inferior hardness. It is a valuable ore when abundant ; but it is seldom smelted alone, because the metal is liable to es- cape with the liberated volatile ingredient. Azurite. Blue Copper Carbonate. Blue Malachite. Monoclinic. In modified oblique rhombic prisms, the crystals rather short and stout ; lateral cleavage perfect. Also mas- sive. Often earthy. Color deep blue, azure blue, Ber- lin blue. Transparent to nearly opaque. Streak bluish. Lustre vitreous, almost adamantine. Brit- tle. H.=3-5-4-5. G. = 3'5-3'85. Composition. Cu 3 7 C 2 + H 2 = Carbon dioxide 25 '6, copper oxide 69*2, water 5-2. B.B. and in acids like the preceding. Obs. Azurite accompanies other ores of copper. Chessy, France, has afforded fine crystals ; found also in Siberia ; in the Banat ; near Redruth in Cornwall ; at Phcenixville, Pa., in crystals ; in Wisconsin near Mineral Point ; as incrusta- tions, and rarely as crystals, near Sing Sing, N. Y. ; near New Brunswick, N. J. ; near Nicholson's Gap, in the Blue Ridge, Pa. When abundant it is a valuable ore of copper. It makes a poor pigment as it is liable to turn green. Aurichalcite (Buratite) is a hydrous copper-and-zinc carbonate, or a cuprous hydrozincite, pale green to sky-blue in color ; from the Altai, Retzbanya, Chessy in France, Tyrol, Spain, Leadhills in Scotland, and Lancaster, Pa. Dioptase. Copper Silicate. Rhombohedral. 72 A # = 126 24'. Occurs in six-sided prisms with rhombohedral terminations. Color emerald- green. Lustre vitreous. Transparent to nearly opaque. H.=5. G. =3-28-3 -35. 142 DESCRIPTIONS OF MINERALS. Composition. CuII 2 4 Si = Silica 38-1, copper oxide 50-4, water 11*5 = 100. B. B. with soda on charcoal yields copper, and this, with its hardness, distinguishes it from the spe- cies it resembles. Obs. From the Khirgeez Steppes of Siberia. Chrysocolla. Hydrous Copper Silicate. Usually as incrustations ; botryoidal and massive. Also in thin seams and stains ; no fibrous or granular structure apparent, nor any appearance of crystallization. Color bright green, bluish green. Lustre of surface of incrustations smoothly shining ; also earthy. Translucent to opaque. H. = 2-4. G. = 2-2 -4. Composition. Cu0 3 Si + 2 aq= Silica 34*2, copper oxide 45-3, water 20-5=100'. NEW JERSEY. Bowen. Beck. . 45.2 42-6 . 37-3 40-0 . 17-0 16-0 _ 1-4 SIBERIAN. Von Kobell. Berthier Oxide of copper. . . 40'0 55*1 Silica 36-5 35 "4 Water 20'2 28'5 Carbonic acid 2'1 Oxide of iron 1-0 The mineral varies much in the proportion of its consti- tuents, as it is not crystallized. B.B. it blackens in the inner flame, and yields water without melting. With soda on charcoal yields a globule of copper. Diff. Distinguished from green malachite as stated under that species. Obs. Accompanies other copper ores in Cornwall, Hun- gary, the Tyrol, Siberia, Thuringia, etc. In Chili it is abundant at the various mines. In Wisconsin and Missouri it is so abundant as to be worked for copper. It was for- merly taken for green malachite. It also occurs at the Som- erville and Schuyler's mines, N. J., at Morgantown, Penn., and Wolcottville, Conn. This ore in the pure state affords 30 per cent, of copper ; but as it occurs in the rock will hardly yield one-third thia amount. Still, when abundant, as it appears to be in the Mississippi Valley, it is a valuable ore. General EemarTcs. The most valuable sources of copper for the arts are native copper, chalcopyrite or "yellow copper ore," chalcocite or "copper glance," bornite or "variegated copper ore," malachite ORES OF COPPER. 143 or " green carbonate of copper," chrysocolla or' silicate," cuprite or "red oxide of copper ; " and occasionally tenorite or " black copper." The principal copper regions, exclusive of the American, are as follows. The Cornwall and Devon, England, where the ere is mostly chalcopyrite ; about Mansfeld, in Prussia, having the ore distributed through a bed of red shale in the Permian (Kupferschiefer), about eighteen inches thick, making about 2^ per cent, of the bed ; the Urals on their western slope, in the Permian, as in Mansfeld ; also more productively on the eastern side of the Urals, at the Nischne Tagilsk and Bogoslowskoi mines, in Silurian limestone where tra- versed by eruptive rocks, and at the Gumeschewskoi mine, in argil- laceous shale, the ore chiefly malachite and cuprite ; in France, at Chessy, near Lyons, of malachite and azurite, now of little value ; in Norway, at Alten, and in Sweden, at Fahlun ; in Hungary, at Scheni- nitz, Kremnitz, Kapnik, and the Banat ; in Italy, at Monte Catini ; in Spain, in the province of Huelva, where is the Rio Tinto mine, which affords chalcopyrite, and also the sulphate (p. 138) ; in Portugal, at San Domingo, near the mouth of the Guadiana ; in Algeria, Turkey, China, Japan, Cape of Good Hope ; in South Australia, where are three prominent mines, the Burra, Wallaroo, and Moonta, their yield in 1875, 451,500 ; New South Wales, the yield in 1875, about 6,000 tons, the value 508,800. In South America, in Chili, in the vicinity of Copiapo, and less abundantly at other places to the south ; in Bolivia, also in Peru, and the Argentine Republic, but not much developed. In Cuba, but much less productive than formerly. In Eastern North America, some copper has been afforded by the ^Triassic of New Jersey and the Connecticut Valley, but there are no 'producing mines. Corinth, Vermont, and the Hiwassee mine, Ten- nessee, are worked. The chief sources of copper are the veins of Northern Michigan, near Lake Superior. The veins are connected with trap-dikes intersecting a red Lower Silurian sandstone as stated on page 131. The first discoveries of copper ore were made at Copper Harbor. Near Fort Wilkins the black oxide was afterward found in a large deposit, and 40,000 pounds of this ore were shipped to Boston. On further exploration in the trap, the Cliff mine, 25 miles to the westward, was laid open, where the largest masses of native copper have been found, and which still proves to be highly productive. Other veins have since been opened in various parts of the region, at Eagle Harbor, Eagle River, Grand Marais, Lac La Belle, Agate Harbor, Torch Lake, on the Ontonagon, in the Porcupine Mountains, and else- where. The country north of Lakes Superior and Huron, IsLe Royale and the Michipicotoii Islands, in Lake Superior, also afford copper ores, and the vicinity of Quebec at the Acton and Harvey Hill mines, in rocks referred to the Quebec formation. In Western North America, in Arizona, there are large veins of copper north of the Gila, on the borders of New Mexico, where are the Santa Rita and Hanover mines, and the ores are cuprite, chalco- cite, malachite ; there are rich veins also in Colorado, especially in Gilpin and Park counties, in Nevada, and California. The amount of copper produced in 1872, is stated as follows by J. Arthur Phillips (Elements of Metallurgy) : 144 DESCRIPTIONS OF MINERALS. England 5,600 tons. Prussia 8,000 Russia 6,500 Hungary 3,500 Sweden and Norway 2,500 Spain 7,500 Portugal 5,500 Japan 1,000 South Australia 12,000 South Africa 7,500 Chili and Bolivia 46,500 United States 12,600 The total annual production is estimated by Phillips at 126,000 to 130,000 tons. The metal copper was known in the earliest periods and was used mostly alloyed with tin, forming bronze. The mines of Nubia and Ethiopia are believed to have produced a great part of the copper of the early Egyptians. Eubsea and Cyprus are also mentioned as afford- ing this metal to the Greeks. It was employed for cutting instru- ments and weapons, as well as for utensils ; and bronze chisels are at this day found at the Egyptian stone-quarries, that were once em- ployed in quarrying. This bronze (chalkos of the Greeks, and ces of the Romans) consisted of about 5 parts of copper to 1 of tin, a propor- tion which produces an alloy of maximum hardness. Nearly the same material was used in early times over Europe ; and weapons and tools have been found consisting of copper, edged with iron, indicating the scarcity of the latter metal. Similar weapons have also been found in Britain ; yet it is certain that iron and steel were well known to the Romans and later Greeks, and to some extent used for warlike" weapons and cutlery. Bronze is hardened by hammering or pressure. Copper knives, axes, chisels, spear heads, bracelets, etc. , have been found in the Indian Mounds of Wisconsin, Illinois, and the neighbor- ing States ; and there is evidence that the Indians, besides using drift masses of copper, knew of the copper veins of Northern Michigan, and worked them, especially in the Ontonagon region, where their tools and excavations have been discovered. Copper at the present day is very various in its applications in the arts. It is largely employed for utensils, for the sheathing of ships, and for coinage. Alloyed with zinc it constitutes brass, and with tin it forms bell-metal as well as bronze. Brass consists of copper 65 per cent., zinc 35 ; with 53 '5 per cent, of zinc the alloy is silver- white ; casting 'brass of 65-72 copper, 35-28 zinc ; or molu or Dutch metal, of 70-85 copper, 15-25 zinc, with 03 of each, lead and tin ; brass for lathe-work of 60-70 copper, 28-38 zinc, 2 lead ; Muntz metal, for the sheathing of ships, 60 copper, 39 zinc, 1 lead ; spelter solder for brass, copper 50, zinc 50. Bronze for medals consists of copper 93, tin 7 ; for speculum metal, copper 60, tin 30, arsenic 10 ; for casting bronze, copper 82-83, tin 1-3, zinc 17-18 ; for gun-metal, copper 85-92, tin 8-15 ; for bell-metal, copper 65-80, tin 20-35, antimony 0-2 ; antique bronze, copper 67-95, tin 8-15, lead 0-1, zinc 0-15. Lord Rosse used for the speculum of his great telescope, 126 parts ORES OF LEAD. 145 of copper to 57| parts of tin. The brothers Keller, celebrated for their statue castings, used a metal consisting of 91 '4 per cent, of cop- per, 5 '53 of zinc, 1/7 of tin, and 1/37 of lead. An equestrian statue of Louis XIV., 21 feet high, and weighing 53,263 French pounds, was cast by them in 1699, at a single jet. An alloy of copper 90, and aluminum 10, is sometimes used in place of bronze. LEAD. Lead occurs rarely native ; generally in combination with sulphur ; also rarely with arsenic, tellurium, selenium, and in the condition of sulphate, carbonate, phosphate and arsenate, chromate and molybdate. The ores of lead vary in specific gravity from 5*5-8-2, They are soft, the hardness of the species with metallic lus- tre not exceeding 3, and others not over 4. They are easily fusible before the blowpipe (excepting plumbo-resinite) ; and with soda on charcoal (and often alone), malleable lead may be obtained. The lead often passes olf in yellow fumes, when the mineral is heated on charcoal in the outer flame, or it covers the charcoal with a yellow coating. Native Lead. A rare mineral, occurring in thin laminae or globules, G. = 11-35. Said to have been seen in the lava of Madeira ; at Alston in Cumberland with galena ; in the County of Kerry, Ireland ; in an argillaceous rock at Carthagena ; at Camp Creek, Montana. Galenite. Galena. Lead Sulphide. Isometric. Cleavage cubic, eminent, and very easily ob- tained. Also coarse or fine granular ; rarely fibrous. 1. Color and streak lead- gray. Lustre shining metallic. Fragile. H.=2-5. G. = 7'25-7-7. 146 DESCRIPTIONS OF MINERALS. Composition. PbS= Sulphur 13-4, lead 86-6 = 100. Often contains some silver sulphide, and is then called argentifer- ous galena ; and at times zinc sulphide is present. The ore of veins intersecting crystalline metamorphic rocks is most likely to be argentiferous. The proportion of silver varies greatly. In Europe, when it contains only 7 or 8 ounces to the ton it is worked for the silver. The galenite of the Hartz affords -03 to *05 per cent, of silver ; the English '02 to -03 per cent. ; that of Leadhills, Scotland, -03 to -06 ; that of Pike's Peak, Colorado, '05 to -06; that of Arkan- sas, -03 to -05 ; that of Middletown, Ct., 15 to -20 ; that of Roxbury, Ct., 1*85 ; that of Monroe, Ct., 3*0 ; while that of Missouri afforded Dr. Litton only '0012 to "002? per cent, A little antimony or cadmium is sometimes present. B.B. on charcoal, it decrepitates unless heated with cau- tion, and fuses, giving off sulphur, coats the coal yellow, and finally yields a globule of lead. Diff. Galenite resembles some silver and copper ores in color, but its cubical cleavage, or granular structure when massive, will usually distinguish it. Its reactions before the blowpipe show it to be a lead ore, and a sulphide. Obs. Galena occurs in granite, limestone, argillaceous and sandstone rocks, and is often associated with ores of zinc, silver and copper. Quartz, barite, or calcite is gener- ally the gangue of the ore ; also at times fluor spar. The rich lead mines of Derbyshire and the northern districts of England, occur in the Subcarboniferous limestone ; and the same rock contains the valuable deposits of Bleiberg, in Austria, and the neighboring deposits of Carinthia. The ore of Cornwall is in true veins intersecting slates and is argentiferous. At Freiberg in Saxony, it occupies veins in gneiss ; in the Upper Hartz, and at Przibram in Bohemia, it traverses clay slate, of Lower Silurian age ; at Sahla, Sweden, it occurs in crystalline limestone. There are other valuable beds of galena, in France at Poullaouen and Hue! oet, Brittany, and at Villefort, department of Lozere ; in pain in the granite and argillyte hills of Linares, in Cata Ionia, Grenada, and elsewhere ; in Savoy ; in Netherlands a Yedrin, not far from Namur ; in Bohemia, southwest o Prague ; in Joachimstahl, where the ore is worked princi pally for its silver ; in Siberia in the Daouria Mountains in limestone, argentiferous and worked for the silver. The deposits of this ore in the United States are remark- ORES OP LEAD. ably for their extent. They occur in limestone, in the States of Missouri, Illinois, Iowa, and Wisconsin ; argillaceous iron ore, pyrite, calamine and smithsonite ("dry bone" of the miners), blende ("black-jack"), carbonate of lead or cerussite, and barite or heavy spar, are the most common associated minerals ; and less abundantly occur chalcopy- rite and malachite, ores of copper ; also occasionally the lead ores, anglesite and pyromorphite ; and in the Mine La Motte region, black cobalt, and linnaeite an ore of nickel. Lead ore was first noticed in Missouri in 1700 and 1701. In 1720 the mines were rediscovered by Francis Renault and M. La Motte ; and the La Motte bears still the name of the latter. Afterward the country passed into the hands of Spaniards, and during that period, in 1763, a valuable mine was opened by Francis Burton, since called Mine a Burton. The lead region of Wisconsin, according to Dr. D. D. Owen, comprises 62 townships in Wisconsin, 8 in Iowa, and 10 in Illinois, being 87 miles from east to west, and 54 miles from north to south. The ore, as in Missouri, is abundant, and throughout the region there is scarcely a square mile in which traces of lead may not be found. The principal indications in the eyes of miners, as stated by Mr. Owen, are the following : fragments of calcite in the soil, unless very abundant, which then indicate that the vein is wholly calcareous or nearly so ; the red color of the soil on the sur- face, arising from the ferruginous clay in which the lead is often imbedded; fragments of lead ("gravel mineral"), along with the crumbling magnesian limestone, and den- dritic specks distributed over the rock; also, a depression of the country, or an elevation, in a straight line ; or " sink- holes ; " or a peculiarity of vegetation in a linear direction. The ore, according to Whitney, occupies chambers or open- ings in the limestone instead of true veins, and in this respect it is like that of Derbyshire and Northern England. The mines of Wisconsin and Illinois are in Lower Silurian limestone of the Trenton period, called the Galena lime- stone ; those of Southeastern Missouri, situated chiefly in Franklin, Jefferson, Washington, St. Frangois, St. Gene- vieve, and Madison counties, are in the " Third Magnesian limestone ; " also Lower Silurian, but, of the Calciferous or Potsdam period ; those of Southwestern Missouri, situated mostly in Newtown, Jasper, Lawrence, Green and Dade counties, and in the western part of McDonald, Barry, DESCRIPTIONS OF MINERALS. Stone, and Christian counties, are in the " Keokuk lime- stone," of the Subcarboniferous period, but partly in Web- ster, Taney, Christian, and Barry counties, in the Lower Silurian "magnesian limestone;" those of Central Mis- souri, situated in Moniteau, Cole, Miller, Morgan, and other counties, are mostly in the Lower Silurian "magnesian limestone," but partly, as in Northern Moniteau, in the Sub- carboniferous. The conditions in which the ore occurs in Missouri confirms the opinion of Prof. Whitney, as to there being no true veins. Mr. Adolf Schmidt, in his account of the Missouri lead ores, says that the deposits contain red clay, broken chert, from the chert bed, and portions of the limestone beds, along with the lead ; that the barite was in troduced after the lead ; that some caves are filled througl all their ramifications, while others arc only partly fille ~ and he adds that the same solvent waters that made the caves and horizontal fissures or openings may have held the vari ous minerals in solution. In Derbyshire, England, the de- posits contain fossils of Permian rocks, showing that, al though occurring in Subcarboniferous limestone, they wen much later in origin. Galenite also occurs in the region of Chocolate River anc elsewhere, Lake Superior copper region ; on Thunder Bay and Black Bay ; at Cave-in-Eock in Illinois, along with fluorite ; in New York at Rossie, St. Lawrence County, in gneiss, in a vein 3 to 4 feet wide ; near Wurtzboro' in Sul- livan County, a large vein in millstone grit ; at Ancram, Columbia County ; Martinsburg, Lewis County, N. Y., and Lowville ; in Maine, at Lubec ; also of less interest at Blue Hill Bay, Birmingham and Parsonsfield ; in New Hampshire, at Eaton, Bath, Tamworth and Haverhill ; in Vermont, at Thetford ; in Massachusetts, at Southampton, Leverett, and Sterling, but without promise to the miner; at Newbury- port, Mass., in a vein which is now worked ; at Middletown, Ct., formerly worked as a silver-lead mine ; in Virginia, i Wythe County, Louisa County, and elsewhere ; in Nort Carolina, at King's Mine, Davidson County, where the lea appears to be abundant ; in Tennessee, ab Brown's Creek and at Haysboro', near Nashville ; in Pennsylvania, a Phcenixville ; in Michipicoton and Spar Islands, Lake Supe- rior. In Nevada it is abundant on Watkins River, and a Steamboat Springs, Galena district ; in Colorado, at Pike's Peak, etc.; in Arizona, in the Patagonian Mts., Santa Rita ORES OF LEAD. 149 Mts., and in Yuma County; in the Castle Dome, Eureka, and other districts, where the ore is worked for the silver it contains. The lead of commerce is obtained from this ore. It is also employed in glazing common stoneware : for this pur- pose it is ground up to an impalpable powder and mixed in water with clay ; into this liquid the earthen vessel is dipped and then baked. Lead Selenides and Tellurides. These various ores of lead are distinguished by the fumes before the blowpipe, and by yielding, on charcoal, ultimately, a globule of lead. Clausthalite, or lead selenide, has a lead-gray color, and granular fracture, and is occasionally foliated. H.=2'5-3. G. =7-6-8*8. B.B. on charcoal a horse-radish odor (that of selenium). From the Hartz. There is a lead and copper selenide (Zorgite) which has the sp. gr. 7-7 '5. A lead-and-mercury selenide (Lehrbachite) occurs in foliated grains or masses of a lead-gray to bluish and iron-black color. Altaite, or lead telluride. A tin- white cleavable mineral, with H. =3 -3'5, and G. =816. From the Altai Mountains. Nagyagite, or Foliated tellurium, is a less rare species, remarkable for being foliated like graphite ; color and streak blackish lead-gray ; H.=1-1'5. G. =7-085. It contains Tellurium 32*2, lead 54'0, gold 9'0, with often silver, copper, and some sulphur. From Transylvania. Antimonial and Arsenical Sulphides of lead. These include Sartorite, Zinkenite, Plagionite, Jamesonite, Dufrenoysite, Boulangerite, Kobel- lite, Meneghinite, Geocronite ; also Brongniardite and Freieslebenite, in which silver is also present, and Stylotypite and Aikenite in which copper is also present. Minium. Oxide of Lead. Pulverulent. Color bright red, mixed with yellow. Gr. = 4 '6. Composition, Pb 3 4 . Affords globules of lead in the reduction flame of the blowpipe. Obs. Occurs at various mines, usually associated with galena, and is found abundantly at Austin's Mines, Wythe County, Virginia, with white lead ore. Uses. Minium is the red lead of commerce ; but for the arts it is artificially prepared. Plumbic ochre is lead protoxide, of a yellow color. Mendipite. Color white, yel>3wish or reddish, nearly opaque. Lustre pearly. G. =7-7-1. PbCl 2 + Pb 0= Chloride of lead 38 '4, lead oxide 61 6. From Mendip Hills, Somersetshire. Cotunnite is a chloride of lead, Pb C1 2 , occurring at Vesuvius in white acicular crystals. It con- tains 74 -5 per cent, of lead. Plumbogummite. In globular forms, having a lustre somewhat like gum arable, and a yellowish or reddish-brown color. H. =4-4*5. 150 DESCRIPTIONS OF MINERALS. G. 6*3-6*4. Also a variety 4-4 -9. Consists of lead, alumina, and water. From Huelgoet in Brittany, and at a lead mine in Beaujeu ; also from the Missouri mines, with black cobalt, and from Canton mine, Ga. Anglesite. Lead Sulphate. Trimetric. In rhombic prisms and other forms. Lateral cleavage. /A 7= 103 43 '. Also massive ; la- mellar or granular. Color white or slightly gray or green. Lustre adamantine ; some- times a litte resinous or vitreous. Transparent to nearly opaque. Brit- tle. H. = .2-75-3. G. = G -1-6 -4. Composition. Pb 0* S, affording about 73 per cent, of oxide of lead. PHCENIXVILLE. B. B. f uses in the flame of a candle, and, on charcoal, yields lead with soda. Diff. Resembles aragonite and some other earthy species ; but this and the other ores of lead are at once distinguished by specific gravity, and also by their yielding lead in blow- pipe trials. Differs from the carbonate of lead in lustre and in not dissolving with effervescence in acid. Obs. Usually associated with galena, and results from its decomposition. Occurs in fine crystals at Leadhills and Wanlockhead, Great Britain, and also at other foreign lead mines. In the United States, it is found at the lead mines of Missouri and Wisconsin ; in splendid crystallizations at Phoenixville, Pa. ; sparingly at the Walton gold mine, Louisa County, Va. ; at Southampton, Mass.; in Arizona, and in Cerro Gordo, Cal. Caledonite is a lead-and-copper sulphate, of azure-blue color. It is remarkable for a very perfect cleavage in one direction. G.=6'4 From Leadhills and Roughten Gill, England; also from MinelaMotte, Missouri. Lead selenate. A sulphur-yellow mineral, occurring in small glob- ules, and affording before the blowpipe on charcoal a garlic odor, and finally a globule of lead. It is named Kerstenite. Crocoite. Crocoisite. Lead Chromate. Monoclinic. In oblique rhombic prisms, massive, of a bright red color and translucent. Streak orange-yellow. G.=5-9-6-l. ORES OF LEAD. Composition. Pb 04 Cr= Chromium trioxide 31-1, lead oxide 68-9. Blackens and fuses, and forms a shining slag containing globules of lead. Obs. Occurs in gneiss at Beresof in Siberia, and also in Brazil. This is the chrome yellow of the painters. Phcenicochroite (or Melanochroite) is another lead chromate, contain- ing 23*0 of chromium trioxide, and having a dark red color ; streak brick-red. Crystals usually tabular and reticulately arranged. G. =5'75. From Siberia. Vauquelinite, A lead and copper chromate, of a very dark green or pearly black color, occurring usually in minute irregularly aggre- gated crystals ; also reniform and massive. H. =2-5-3. G. =5*5-5 '8. From Siberia and Brazil ; also at the lead mine near Sing Sing, in mammillary concretions. Stolzite, or lead tungstatc. In square octahedrons or prisms. Color green, gray, brown, or red. Lustre resinous. H. =2*5-3. G. 7'9- 81. Contains 51 of tungstic acid and 49 of lead. Wulfenite, or lead molybdate. In dull-yellow octahedral crystals, and also massive. Lustre resinous. Contains molybdenum trioxide 34*25, protoxide 64 '43. From Bleiberg and elsewhere in Carinthia ; also Hungary. It has been found in small quantities in the Southamp- ton lead mine, Mass. , and in fine crystals, at Phcenixville, Penn. Lead SulpJialo-carbonates. There are two whitish or grayish ores of this composition called Lanarkite and Leadhillite. The former con- tains 71 per cent, of carbonate of lead ; the latter, 47. Pyromorphite. Lead Phosphate. Hexagonal. In hexagonal prisms ; often in crusts made of crystals. Also in globules or reniform, with a radiated structure. Color bright green to brown ; sometimes fine orange-yellow, owing to an intermix- ture with cfiromate of lead. Streak white or nearly so. Lustre more or less resinous. Nearly transparent to subtranslucent. Brit- tle. H. =3-5-4. G. = 6-5-7 -1. Composition. Pb s 8 P 2 + Pb C1 2 = Phos- phorus pentoxide 15 '71, lead oxide 82-27, chlorine 2 -62 = 100-60. B.B. fuses easily in the forceps, coloring the flame bluish green. On charcoal fuses, and on cooling, the globule becomes angular ; the coal is coated white from the chloride, and nearer the assay, yellow from lead oxide. Soluble in nitric acid. Diff. Has some resemblance to beryl and apatite ; but is quite different in its action before the blowpipe, and much higher in specific gravity. 152 DESCRIPTIONS OF MINERALS. Obs. Leadhills, "Wanlockhead, and other lead mines of Europe are foreign localities. In the United States, very handsome crystallized specimens occur at King's Mine, in Davidson County, N. C. ; other localities are the Perkiomen and Phoenixville mines, Pa. ; the Lubec lead mines, Me. ; Lenox, N. Y. ; formerly, a mile south of Sing Sing, N. Y. ; and the Southampton lead mine, Mass. The name pyromorpMte is from the Greek pur, fire, and morplie, form, alluding to its crystallizing on cooling from fusion before the blowpipe. Mimetite. A lead arsenate, resembling pyromorphite in crystalliza- tion, but giving a garlic odor on charcoal before the blowpipe. Color pale yellow, passing into brown. H. =2*75-3*5. G. =6*41. Com- position, Pb 3 O 8 As 7 + 14 PbCl 2 = Arsenic pentoxide 23*20, lead oxide 74*96, chlorine 2 *30 =100 '55. From Cornwall and elsewhere ; Phce- nixville, Pa. Hedyphane is a variety of mimetite containing much lime. It occurs amorphous, of a whitish color, and adamantine lustre. H. = 3-5-4. G. =5-4-5 -5. Karyinite. A lead arsenate containing manganese and calcium, from Norway. Ecdemite. A lead chloro-arsenate. Vanadinite. A lead vanadate occurring in hexagonal prisms like pyromorphite, and also in implanted globules. Color yellow to red- dish brown. H. =2 -75-3. G. =6*6-7 '3. From Mexico; also from Wanlockhead in Dumfriesshire. Monimolite. A yellow lead antimonate. Nadorite. A yellow lead chlor-antimonate. Bindheimite. A hydrous lead antimonate. Cerussite. White Lead Ore. Lead Carbonate. Trimetric. In modified right rhombic prisms, and often in compound crystals, two or three crossing one another as 1. 2. in fig. 2. /A 1=117 13'. Also in six-sided prisms like aragonite. Also massive ; rarely fibrous. Color white, grayish, light or dark. Lustre adamantine. Brittle. H. = 3-3 -5. G. = 6 46-6 -48. LEAD. 153 Composition. Pb 3 = Carbon dioxide 16*5, lead oxide 83-5 = 100. B.B. decrepitates, fuses, and with care on char- coal affords a globule of lead. Effervesces in dilute nitric acid. Diff. Like anglesite, distinguished from most of the spe- cies it resembles by its specific gravity and yielding lead when heated. From anglesite it differs in giving lead alone before the blowpipe, as well as by its solution and efferves- cence with nitric acid, and its less glassy lustre. Obs. Associated usually with galena. Leadhills, Wan- lockhead, and Cornwall have afforded splendid crystalliza- tions ; also Linares, in Spain, and other lead mines on the continent of Europe. In the United States, handsome specimens are obtained at Austin's Mines, Wythe County, Virginia, and at King's Mine, in Davidson's County, North Carolina ; at the latter place it has been worked for lead, and it is associated with native silver and pyromorphite. Perkiomen and Phoenix- ville, Penn., afford good crystals. It occurs also at "Vallee's Diggings," Jefferson County, Missouri, and other mines, in that State ; at Brigham's Mine, near the Blue Mounds, Wisconsin, partly in stalactites ; at " Deep Diggings," in crystals ; and at other places, both massive and in fine crystallizations. When abundant, this ore is wrought for lead. Large quantities occur about the mines of the Mississippi Valley. It was formerly buried up in the rubbish as useless, but it has since been collected and smelted. It is an exceedingly rich ore, affording in the pure state 75 per cent, of lead. Carbonate of lead is the " white lead " of commerce, so extensively used as a paint. The material for this purpose is, however, artificially made. Phosgenite or Corneous Lead. A cliloro-earbonate of lead, occurring in whitish adamantine crystals. H.=r2*75-4. G. =6-6 31. Composi- tion, Pb0 3 C+PbCl 3 . From Derbyshire and Germany. Hydrocerussite. Hydrous lead carbonate. From Sweden. Ganomal'te is a white lead-manganese silicate, affording 34 89 per cent, of lead oxide. From Sweden. Hyalotccite is a lead-barium-lime silicate. Both are from Longban, Sweden. General Eemarks. The lead of commerce is derived almost wholly from the sulphide of lead or galenite, the localities of which have already been mentioned. In some mining regions, the carbonate and sulphate are abundant. The lead mines of the Central United States afforded in 1826, 1,770 tons ; iu 1842, 17,340 tons ; and of late years, 12,000 to 15,000 tons. 154 DESCRIPTIONS OF MINERALS. Nevada produced 10,000 tons in 1870, and 50,000 in 1875. According to Phillips, England produced in 1872, (50,450 tons ; Prussia, in 1871, 49,500 tons ; Spain, in 1873, 102,600 tons ; France, 2,500 tons ; Italy, 15,500 tons ; Austria, 10,000 tons. ZINC. Zinc occurs in combination with sulphur and oxygen ; and also in the condition of silicate, carbonate, sulphate, and arsenate. It is also a constituent of one variety of the species spinel. The chief sources of the metal are smith- sonite or the carbonate ; willemite and calamine, or sili- cates ; zincite, or the oxide ; sphalerite (blende), or the sulphide ; and franklinite. Sphalerite. Blende. Zinc Sulphide. Isometric. In dodecahedrons, octahedrons, and other allied forms, with a perfect dodecahedral cleavage. Also massive ; sometimes fibrous. Color wax-yellow, brownish-yellow, to black, sometimes green, red and white ; streak white, to red- dish brown. Lustre resinous or waxy, and brilliant on a cleavage face ; sometimes submetallic. Transparent to sub- translucent. Brittle. H.=3-5-4. G. =3 -9-4 '2. Some specimens become electric with friction, and give off a yel- low light when rubbed with a feather. Composition. ZnS = Sulphur 33, zinc 67 = 100. Contains frequently a portion of iron sulphide when dark colored ; often also 1 or 2 per cent, of cadmium sulphide, especially the red variety. Nearly infusible alone and with borax. Dissolves in nitric acid, emitting sulphuretted hydrogen. Strongly heated on charcoal yields fumes of zinc. Diff. This ore is characterized by its waxy lustre, perfect cleavage, and its being nearly infusible. Some dark varieties look a little like tin ore, but their cleavage and inferior hardness distinguish them ; and some clear red crystals, ZINC. 155 which resemble garnet, are distinguished by the same char- aracters and also by their very difficult fusibility. Obs. Occurs in rocks of all ages, and is associated gener- ally with ores of lead ; often also with copper, iron, tin, and silver ores. The lead mines of Missouri and Wisconsin afford this ore abundantly. Other localities are in Maine, at Lu- bec, Bingham, Dexter, Parsonsfield ; in New Hampshire, at Eaton, Warren, Haverhill, Shelburne ; in Vermont, at Hatfield ; in Connecticut, in Brooktield, Berlin, Roxbury, and Monroe ; in New York, at Ancram lead mine, the Wurtzboro' lead vein, at Lockport, Root, 2 miles southeast of Spraker's Basin, in Fowler, at Clinton ; at Franklin, N. J., colorless (Cleiophane) ; in Pennsylvania, at the Perkio- men lead mine ; in Virginia, at Austin's lead mine, Wythe County; in Tennessee, near Powell's River, and at Haysboro'; at Prince's Mine, Spar Island, Lake Superior, with ores of sil- ver ; in Beauce Co., Canada, where it is slightly auriferous. This ore is the Black-jack of miners. Blende is a useful ore of zinc, though more difficult of re- duction than calamine. By its decomposition (like that of pyrite), it affords sulphate of zinc or white vitriol. Wurtzlte is zinc sulphide in hexagonal crystals from Bolivia. Huas- colite and Youngite are zinc-lead sulphides. Zincite, Red Zinc Ore. Red Zinc Oxide. Hexagonal. Usually in foliated masses, or in disseminated grains ; cleavage eminent, nearly like that of mica ; but the laminae brittle, and not so easily separable. Color deep or bright red ; streak orange-yellow. Lustre brilliant, subadamantine. Translucent or subtranslucent. H. =4-4-5. G. =5-4-5 -7. Thin scales by transmitted light deep yellow. Composition. Zn = Oxygen 19-7, zinc 80-3 = 100. B.B. infusible alone, but yields a yellow transparent glass with borax ; on charcoal, a coating of zinc oxide. Dissolves in nitric acid without effervescence. Diff. Resembles red stilbite, but distinguished by its in- fusibility and also by its mineral associations. Obs. Occurs witli franklinite at Mine Hill and Sterling Hill, Sussex County, N. J. A good ore of zinc, and easily reduced. Voltzite. A compound of sulphur, oxygen and zinc, 4 Zn S +Zn O. Occurs in implanted globules of a dirty rose-red color, with a pearly lustre on a cleavage surface. From France, and near Joachimstahl. 156 DESCRIPTIONS OP MINERALS. Goslarite. Sulphate of Zinc. White Vitriol. Trimetric. Cleavage perfect in one direction. / A /= 90 42'. Color white. Lustre vitreous. Easily soluble ; taste as- tringent, metallic, and nauseous. Brittle. H. =2-2-5. G.= 1-9-2-1. Composition. Zn0 4 S + 7 aq. =Zinc oxide 28-2, sulphur trioxide 27*9, water 43-9 = 100. B.B. gives off fumes of zinc on charcoal, which cover the coal. Obs. Eesults from the decomposition of blende. Occurs in the Hartz, in Hungary, in Sweden, and at Holywell in Wales. Sulphate of zinc is extensively employed in medicine and dyeing. For these purposes it is prepared to a large extent from blende by decomposition, though this affords, owing to its impurities, an impure sulphate. It is also obtained by direct combination of zinc with sulphuric acid. White Vitriol, as the term is used in the arts, is one form of sulphate of zinc, made by melting the crystallized sul- phate, and agitating till it cools and presents an appearance .like loaf sugar. Kottigite. A hydrous zinc-cobalt arsenate of reddish color (owing to presence of cobalt) from Schneeberg Adamite. A hydrous zinc-arsenate of honey -yellow to violet color, from Chili. Smithsonite. Carbonate of Zinc. Ehombohedral. R A 72=107 40'. Cleavage R perfect. Massive or incrusting ; reniform and stalactitic. Color impure white, sometimes green or brown ; streak uncolored. Lustre vitreous or pearly. Subtransparent to translucent. Brittle. H.=5. G. =4-3-4-45. Composition. Zn0 3 C = Carbon dioxide 35 -2, zinc oxide 64-8 (four-fifths of which is pure zinc) = 100. Often con- tains some cadmium. B.B. infusible alone, but carbonic xicid and oxide of zinc are finally vaporized. Effervesces in nitric acid. Negatively electric by friction. Diff. The effervescence with acids distinguishes this mineral from the following species ; and the hardness, diffi- cult fusibility, and the zinc fumes before the blowpipe, from the carbonate of lead or other carbonates. Besides, the crystals over a drusy surface terminate usually in sharp three-sided pyramids. ZINC. 157 Obs. Occurs commonly with galena or blende, and usual- ly in calcareous rocks. Found in Siberia, Hungary, Sile- sia ; at Bleiberg in Carinthia ; near Aix-la-Chapelle in the Lower Rhine, and largely in Derbyshire and elsewhere in England. In the United States, it is abundant at Vallee's Diggings in Missouri, and at other lead " diggings" in Iowa and Wisconsin ; also in Claiborne County, Tenn. Sparingly also at Hamburg, near the Franklin Furnace, N. J. ; at the Perkiomen lead mine, Pa., and at a lead mine in Lancaster County. Hydrozincite is a hydrous zinc carbonate, ZnO 3 C+ 2 Zn0 2 H, of a whitish color, with G.=3'58-3'8. Aurichaldte is a hydrous carbonate of zinc and copper, occurring in drusy incrustations of acicular crystals, having a pale verdigris-green color. From Siberia, Hungary, England, and Lancaster, Pa. Buratite is a liine aurichalcite. Willemite. Zinc Silicate. Troostite. Ehombohedral. R A 72=116 1'. In hexagonal prisms, and also massive. Color whitish, greenish yellow, apple-green, flesh-red, yel- lowish brown. Streak uncolored. Transparent to opaque. Brittle. H.=:5-5, G.=3-89-4-18. Composition. Zn 3 Si = Silica 27*1, zinc oxide 72 '9 = 100. B.B. fuses with difficulty to a white enamel ; on char- coal, and most easily on adding soda, yields a coating which is yellow while hot, and white on cooling, and which, moistened with cobalt solution and treated in O.F., is colored bright green. Gelatinizes with hydrochloric acid. Obs. From Moresnet, between Liege and Aix-la-Chapelle ; Raibel in Carinthia ; Greenland. Abundant at both Frank- lin and Sterling, mixed with zincite, and used as an ore of zinc ; also in prismatic crystals that occasionally are six inches long. Calamine. Hydrous Zinc Silicate. Galmei. Trimetric. In rhombic prisms, the opposite extremities with unlike planes. / A /=104 13'. Cleavage perfect parallel to /. Also massive and inerusting, mammillated or stalactitic. Color whitish or white, sometimes bluish, greenish, or brownish. Streak uncolored. Transparent to translucent. Lustre vitreous or subpearly. Brittle. H.=4'5-5. Gr. = 3-16-3*9. Pyro-electric. 158 DESCRIPTIONS OP MINERALS. Composition. Zn 2 4 Si + aq. = Silica 25'0, zinc oxide 67'5, water 7'5 = 100. B.B. alone it is almost infusible. Forms a clear glass with borax. In heated sulphuric acid it dissolves, and the solution gelatinizes on cooling. Diff. Differs from calcite and aragonite by its action with acids ; from a salt of lead, or any zeolite, by its infusibility ; from chalcedony by its inferior hardness, and its gelatiniz- ing with heated sulphuric acid ; and from smithsonite by not effervescing with acids, and by the rectangular aspect of its crystals over a drusy surface. Obs. Occurs with calamine. In the United States it is found at Vallee's Diggings, Mo.; at the Perkiomen and Pho3nixville lead mines ; on the Susquehanna, opposite Selinsgrove ; at Friedensville in Saucon Valley, two miles from Bethlehem, Pa,, with massive blende. Abundantly at Austin's Mines, Wythe County, Va. Valuable as an ore of zinc. Hopeite is a rare mineral occurring in grayish-white crystals or mas- sive, with calamine, and supposed to be a hydrous zinc-phosphate. Franklinite, an ore of iron, manganese and zinc, is described under iron, on page 179. General Remarks. The metal zinc (spelter of commerce) is supposed to have been unknown in the metallic state to the Greeks and Romans. It has been long worked in China, and was formerly imported in large quantities by the East India Company. The principal mining regions of zinc in the world arc in Upper Sile- sia, at Tarnowitz and elsewhere ; in Poland ; in Carinthia, at Eaibel and Bleiberg ; in Netherlands at Llmberg ; at Altenberg, near Aix-la- Chapelle in the Prussian province of the Lower Rhine ; in England, in Derbyshire, Alstonmoor, Mendip Hills, etc. ; in the Altai in Eussia ; besides others in China, of which little is known. In the United States, smithsonite and calamine occur with the lead of the West in large quantities. They were formerly considered worthless and thrown aside, under the name of " dry bone." In Tennessee, Claihorne County, there are workable mines of the same ores. Calamine occurs at Friedensville, Pennsylvania, along with massive blende : the bed has been, but is not now worked. The zincite, willemite, and frank- linite of Franklin, New Jersey, are together worked as a zinc ore, and both zinc and zinc oxide are produced. Blende is sufficiently abun- dant to be worked at the Wurtzboro' lead mine, Sullivan County, New York ; at Eaton and Warren, in New Hampshire : at Lubec, in Maine ; at Austin's Mine, Wythe County, Virginia, and at some of the Missouri lead mines. The amount of zinc produced in 1872, in Europe, was about 45,745 tons for Belgium ; 55,744 for Germany ; 3,000 for Austria : 15,000 for Great Britain ; 4,400 for France ; 4,400 for Spain : making the total amount 128,289 tons. In the United States the amount of zinc made in 1875 was about 15,000 tons ; of zinc oxide, 8,500 tons. TIN. 159 Zinc is a brittle metal, but admits of being rolled into sheets when heated to about 21 2 F. In sheets it is extensively used for roofing and other purposes, it being of more difficult corrosion, much harder, and also very much lighter than lead. It is also employed largely for coating (that is, making what is called galvariized) iron. Its alloys with copper (page 144) are of great importance. The white oxide of zinc is much used for white paint, in place of white lead ; and also in making a glass for optical purposes. An impure oxide of zinc, called cadmia, often collects in large quan- tities in the flues of iron and other furnaces, derived from ores of zinc mixed with the ores undergoing reduction. A mass weighing 600 pounds was taken from a furnace at Bennington, Vt. It has been ob- served in the Salisbury iron furnace, and at Ancram, in New Jersey, where it was formerly called Ancramite. CADMIUM. There is but a single known ore of this rare metal. It is a sulphide, and is called Greenockite. It occurs in hexagonal prisms, with dissimilar pyramidal termination, of a light yellow color, high lustre, and nearly transparent. H. =3- 3-5. G. =4-8-5. From Bishopton, Scotland. Cadmium is often associated with zinc in sphalerite and calamine. The cadmiferous sphalerite is called Przibramite. The metal cadmium is white like tin, and is so soft that it leaves a trace upon paper. It fuses at 442 F. It was discovered by Stromeyer in 1818. TIN. Tin has been reported as occurring native in the gold washings of the Ural, and in Bolivia. There are two ores, a sulphide and an oxide. It also occurs in some ores of columbium, tantalum, and tungsten. Stannite. Tin Pyrites, Sulphuret of Tin. Tin Sulphide. Commonly massive, or in grains. Color sfceel-gray to iron- black ; streak blackish. Brittle. H.=4. G. =4-3-4 -6. Composition. Sulphur 30, tin 27, copper 30, iron 13 = 100. Obs. From Cornwall, where it is often called lell-metal ore? from its frequent bronze appearance ; also from Ireland and the Erzgebirge. 160 DESCRIPTIONS OF "MINERALS. Cassiterite. Tin Ore. Tin Oxide. Dimetric. 1. In square prisms and octahedrons; often com- 2. pounded. 1 A 1 = 121 40' ; 1 i Al i (over the summit) 112 10', (over a terminal edge) 133 31'. Cleavage indistinct. Also massive, and in grains. Color brown or black, with . a high adamantine lustre when in crystals. Streak pale gray to brownish. Nearly trans- parent to opaque. H.=6-7. G.= 6-4-7-1. Composition. Sn 2 = Oxygen 21*33, tin 78-67 ; often con- tains a little iron, and sometimes tantalum. B.B. alone infusible. On charcoal with soda, affords a -globule of tin. Stream tin is the gravel-like ore found in debris in low grounds. Wood tin occurs in botryoidal and reniform shapes with a concentric and radiated structure ; and toads-eye tin is the same on a small scale. Diff. Tin ore has some resemblance to a dark garnet, to black zinc blende, and to some varieties of tourmaline. It is distinguished by its infusibility, and its yielding tin before the blowpipe on charcoal with soda. It differs from blende also in its superior hardness. Obs. Tin ore occurs in veins in the crystalline rocks, granite, gneiss, and mica slate, associated often with wolfram, copper and iron pyrites, topaz, tourmaline, mica or talc, and albite. Cornwall is one of its most productive localities. It is also worked in Saxony, at Altenberg, Geyer, Ehren- friedersdorf and Zinnwald; in Austria, at Schlackenwald and other places ; in Malacca, Pegu, China, and especially the Island of Banca in the East Indies ; in Queensland and Northern New South Wales, Australia, in large quantities ; in Greenland. It occurs* also in Galicia, Spain ; at Dale- carlia in Sweden ; in Russia ; in Mexico at Durango; and Bolivia. In the United States it has been found spar- ingly at Chesterfield and Goshen, Mass.; in some of the Vir- ginia goldmines ; in Lyme and Jackson, N. H. ; and in the Temescal Range, California. General Remarks. The principal tin mines now worked, are those of Cornwall, Banca, Malacca, and Australia. The Cornwall mines were worked long before the Christian era. TIN. 161 Herodotus, 450 years before Christ, is believed to allude to the tin islands of Britain under the cabalistic name Cassiterides, derived from the Greek kassiteros, signifying tin. The Phoenicians are allowed to have traded with Cornubia (as Cornwall was called, it is supposed from the horn-like shape of this extremity of England). The Greeks residing at Marseilles were the next to visit Cornwall, or the isles ad- jacent, to purchase tin ; and after them came the Romans, whose merchants were long foiled in their attempts to discover the tin market of their predecessors. Camdeu says : " It is plain that the ancient Britons dealt in tin mines from the testimony of Diodorus Siculus, who lived in the reign of Augustus, and Timaus, the historian in Pliny, who tells TIS that the Britons fetched tin out of the Isle of Icta (the Isle of Wight), in their little wicker boats covered with leather. The import of the passage in Diodorus is that the Britons who lived in those parts dug tin out of a rocky sort of ground, and carried it in carts at low water to certain neighboring islands ; and that from thence the merchants first trans- ported it to Gaul, and afterwards on horseback in thirty days to the springs of Eridanus, or the city of Narbona, as to a common mart. JEthicus too, another ancient writer, intimates the same thing, and adds that he had himself given directions to the workmen." In the opinion of the learned author of the Britannica here quoted, and others who have followed him, the Saxons seem not to have meddled with the mines, or, according to tradition, to have employed the Saracens ; for the inhabitants of Cornwall to this day call a mine that is given over working Attal-Sarasin, that is, the leavings of the Saracens. The Cornwall veins, or lodes, mostly run east and west, with a dip hade, in the provincial dialect varying from north to south ; yet they are very irregular, sometimes crossing each other, and sometimes a promising vein abruptly narrows or disappears ; or again they spread out into a kind of bed or floor. The veins are considered worth work- ing when but three inches wide. The gangue is mostly quartz, with some chlorite. Much of the tin is also obtained from beds of loose stones or gravel (called sh'tdes^, and courses of such gravel or tin de- bris are called streams, whence the name stream tin. The Australian mines are mainly in the New England district of Northern New South Wales, and the adjoining part of Queensland, and a large part of the ore goes north through Queensland. The value of the tin exported in 1875 from Queensland was 88,2*24, and from New South Wales (Ann. Rep. Dept. of N. S. W. Mines, 1876), 561,311, cor, responding to 6,058 tons of tin in ingots, besides 2,0?2 tons of ore. The value of all the tin raised in N. S. Wales, prior to 1875 is 866,461. Beechwood, Victoria, also affords a little tin. The annual production of tin in 1871 in Great Britain was 11,320 tons, and in Banca and Malacca, 7,500. Tin is used in castings, and also for coating other metals, especially iron and copper. Copper vessels thus coated were in use among the Romans, though not common. Pliny says that the tinned articles could scarcely be distinguished from silver, and his use of the words incoquere and incoctilia seems to imply, as a writer states, that the process was the same as for the iron wares of the present day, by im- mersing the vessels in melted tin. Its alloys with copper are mentioned on page 144. 162 DESCRIPTIONS OF MINERALS. Tin is also used extensively as tinfoil ; but most tinfoil consists be* neath the surface of lead, and is made by rolling out plates of lead coated with tin. With quicksilver it is used to cover glass in the manufac- ture of mirrors. Tin oxide (dioxide), obtained by chemical processes, is employed, on account of its hardness, in making a paste for sharp- ening fine cutting instruments, and also to some extent in the prepara. tion of enamels. The chlorides of tin are important in the precipita- tion of many colors as lakes, and in fixing and changing colors in dye- ing and calico-printing. The bisulphide has a golden lustre, and wa^ termed aurum musivum, or mosaic gold, by the alchemists. It ismucr used for ornamental painting, for paper-hangings and other purposes, under the name of bronze powder. TITANIUM. Titanium occurs in nature combined with oxygen, form- ing titanium dioxide or titanic acid, and also in oxygen com- binations with iron and calcium, and in some silicates. It has not been met with native. The ores are infusible alone before the blowpipe, or nearly so. Their specific gravity is between 3-0 and 4-5. Rutile. Dimetric. In prisms of four, eight, or more sides, with pyramidal terminations, and often bent as in the figure; lAl = 123 7J'. Crystals often acicular, and penetrating quartz. Some- times massive. Cleavage lateral, somewhat distinct. Color reddish-brown to nearly red ; streak very pale brown. Lustre submetallic-ada- mantine. Transparent to opaque. Brittle. H. =6-6-5. G. =4-15-4 -25. Composition. Ti 2 = Oxygen 39, titanium 61 = 100. Sometimes contains iron, and lias nearly a black color ; this variety is called Nigrine. B.B. alone unaltered ; with salt of phosphorus a colorless bead, which in the reducing flame becomes violet on cooling. Diff. The peculiar subdamantine lustre of rutile, and brownish-red color, much lighter red in splinters, are striking characters. It differs from tourmaline, idocrase, and augite, by being unaltered when heated alone before the blowpipe ; and from tin ore, in not affording tin with soda ; from ephene in its crystals. COBALT AND NICKEL. 163 Obs. Occurs imbedded in granite, gneiss, mica schist sye- nyte, and in granular limestone. Sometimes associated with hematite, as at the Grisons. Yrieix in France, Castile, Brazil, and Arendal in Norway, are some of the foreign localities. In the United States, it occurs in crystals in Maine, at "Warren ; in New Hampshire, at Lyme and Hanover ; in Massachusetts, at Barre, Windsor, Shelburne, Leyden, Con- way ; in Connecticut, at Monroe and Hunting-ton ; in New York, near Edenville, Warwick, Amity, at Kingsbridge, and in Essex County at Gouverneur ; in Pennsylvania, in Chester County ; in the District of Columbia, at Georgetown ; in North Carolina, in Buncombe County ; in Georgia, in Lin- coln and Ilabersham counties ; at Magnet Cove in Arkansas. The specimens of limpid quartz, penetrated by long aci- cular crystals, are often very handsome when polished. A re- markable specimen of this kind was obtained in Northern Vermont, and less handsome ones are not uncommon ; they are found in North Carolina. Polished stones of this kind are c&Ned. fleches (T amour (love's arrows) by the French. This ore is employed in painting on porcelain, and quite largely for giving the requisite shade of color and enamel appearance to artificial teeth. Octahedrite (Anatase) ; Brookite. These species have the same com- position as rutile. Octahedrite occurs in slender nearly transparent octahedrons, of a brown color. lAl=97 51'. H. = 5'5-6. G.=3'8- 3-95. From Dauphiny, the Tyrol, and Brazil ; at Smithfield, R. I. Brookite is met with in thin hair-brown flat trimetric crystals, at- tached by one edge. Also in thick iron-black crystals, as in the va- riety called Arkansite. H. 5 '5-6. From Dauphiny; Snowdon in Wales ; Ellenville, Ulster County, N. Y. ; Paris, Maine ; gold wash- ings of North Carolina ; Magnet Cove, Arkansas (Arkansite). Perofskite. In cubic crystals, of yellow, brown, and black colors ; chemical formula (Ti, Ca) a O 3 . From the Urals, the Tyrol, and Magnet Cove, Arkansas. Besides the ores here described, titanium is an essential constituent also of ilmenite (titanic iron), and of the silicates titanite or sphene (p. 290), keilliauite (p. 291), wanoickite ; and occurs also in the zir- conia and yttria ores ceschynite, cerstcditc, and polymignite, and in some other rare species ; sometimes in pyrochlore. COBALT, NICKEL. Cobalt has not been found native. The ores of cobalt are sulphides, arsenides, arseno-sulphides, an oxide, a car- bonate, a phosphate, and an arsenate; and nickel is often 164 DESCRIPTIONS OP MINERALS. associated with cobalt in the sulphides and arsenides. The ores having a metallic lustre vary in specific gravity from 6 -2 to 7 '2 ; and the color is nearly tin-white or pale steel, gray, inclined to copper-red. The ores without a metallic lustre have a clear red or reddish color, and specific gravity of nearly 3. Cobalt is often present also in arsenopyrite (or mispickel), and sometimes in pyrite. The ores of nickel are sulphides, arsenides, arseno-sulph- ides, and anti mono-sulphides, a sulphate, carbonate, silicates, arsenate ; and the metal is a constituent of several cobalt ores, and also often of pyrrhotite (magnetic pyrites). Specific gravity between 3 and 8 ; hardness of one 3, but mostly be- tween 5 and 6. Those of metallic lustre resemble some cobalt ores ; but they do not give a deep blue color with borax. Linnaeite. Cobalt Sulphide. Cobalt and Nickel Sulphide. Isometric. In octahedrons and cubo-octahedrons ; also massive. Color pale steel-gray, tarnishing copper red. Streak blackish gray. H. = 5 -5. G. = 4 -8-5. Composition. Co 3 S 4 = Sulphur 42 -0, cobalt 5 -80 = 100 ; but with part of the cobalt replaced by nickel ; copper some- times present. Siegenite is a variety containing 30 to 40 per cent, of nickel. B.B. on charcoal yields sulphurous odor and a magnetic globule ; often also arsenical fumes. Obs. From Sweden, Prussia ; Mine la Motte in Missouri (Siegenite) ; Mineral Hill in Maryland. Sometimes called cobalt pyrites. Millerite. Nickel Sulphide. Capillary Pyrites. Ehombohedral. Usually in capillary or needle-like crys" tallizations ; sometimes like wool. Also in columnar crusts and radiated. Color brass-yellow, inclining to bronze-yellow, with often a gray iridescent tarnish. Streak bright. Brittle. H.=3-3-5. G. =4-6-5 -65. Composition. Ni S = Sulphur 35-6, nickel 64-4=100. In the open tube sulphurous fumes. B.B. on charcoal fuses to a globule ; and after roasting, gives, with borax and salt of phosphorus, a violet bead in O.F., which in K.F. becomes gray from reduced metallic nickel. COBALT AND NICKEL. 165 Obs. From Joachimstahl, Przibram, Kiechelsdorf ; Sax- ony ; Cornwall ; at the Sterling Mine, Antwerp, N. Y.; at the Gap Mine, Lancaster Co., Pa.; at St. Louis, Mo., in capillary forms, and sometimes wool-like, in cavities in mag- nesian limestone. A valuable ore of nickel. Beyrichite has the formula Ni 5 S 7 . Smaltite. Cobalt Glance. Chloanthite. Isometric. Occurs in octahedrons, cubes, and dodecahe- drons, and other forms. See figs. 1, 2, 3, page 17, and 17, 27, page 20. Cleavage octahedral, somewhat distinct. Also reticulated ; often massive. Color tin-white, sometimes inclining to steel-gray. Streak grayish black. Brittle. Fracture granular and uneven. Composition. (Co, Ni) As 2 ; the ore being either a cobalt arsenide, or cobalt-nickel arsenide ; and graduating into the nickel arsenide called Chloanthite. The cobalt in the ore may constitute 23*5 per cent. ; but it may be wholly absent as in the chloanthite. In addition, iron often replaces part of the other metals, as in the variety Safflorite. In the closed tube gives a sublimate of metallic arsenic ; in the open tube a white sublimate of arsenous oxide, and sometimes traces of sulphurous acid. B.B. on charcoal, affords an arsenical odor, fuses to a globule which gives re- action for iron, cobalt, and nickel. Diff. Arsenopyrite (mispickel) has tho white color of smaltite, but it yields sulphur as well as arsenic, and in a closed tube affords arsenic sulphide, orpiment and realgar. Obs. Usually in veins with ores of cobalt, silver, and copper. Occurs in Saxony, especially at Schneeberg ; also in Bohemia, Hessia, and Cornwall. In the United States it is found in gneiss with copper nickel (niccolite), at Chatham, Conn. Cobaltite. Isometric. Crystals like those of pyrite, but silver-white in color with a tinge of red, or inclined to steel-gray. Streak grayish black. Brittle. H. = 5 -5. G. = 6 -63. Composition. CoS 2 + Co As 2 = Co AsS = Arsenic 45-2, sul- phur 19-3, cobalt 35-5 = 100, but often with much iron and occasionally a little copper. Unaltered in the closed 16(> DESCRIPTIONS OF MINERALS. tube ; but in the open tube, yields sulphurous fumes and a white sublimate of arsenous oxide. B.B. on charcoal yields sulphur and arsenic and a magnetic globule ; with borax a cobalt-blue globule. Diff. Unlike smaltite affords sulphur, and has a reddish tinge in its white color. Obs. From Sweden, Norway, Siberia, and Cornwall. Most abundant in the mines of Wehna in Sweden, first opened in 1809. Niccolite. Copper Nickel. Arsenical Nickel. Hexagonal. Usually massive. Color pale copper-red. Streak pale brownish-red. Lustre metallic. Brittle. H. = 5-5-5. G. = 7-3-7-7. Corn-position. Ni As Nickel 44, and arsenic 56 ; some- times part of the arsenic is replaced by antimony. Gives off arsenical (alliaceous) fumes before the blowpipe, and fuses to a pale globule, which darkens on exposure. Assumes a green coating in nitric acid, and is dissolved in aqua-regia. Diff. Distinguished from pyrite and linnaeite by its pale reddish shade of color, and also its arsenical fumes, and from much of the latter by not giving a blue color with borax. None of the ores of silver with a metallic lustre have a pale color, excepting native silver itself. Obs. Accompanies cobalt, silver, and copper ores in the mines of Saxony, and other parts of Europe ; also sparingly in Cornwall. It is found at Chatham, Conn., in gneiss, associated with white nickel or cloanthite. Skutterudite. A cobalt arsenide of the formula Co As 3 , from Skut- terud, Norway. Breithauptite or Antimonicd Nickel. Ni Sb= Antimony 67 '8, nickel 32-2 = 100. It has a pale copper-red color, inclining to violet. H. 5'5 -6. G.=7'54 Crystals hexagonal. From Andreasberg. Gersdorffite. A nickel arsenosulphide ; NiS 2 + Ni As 2 =:Ni AsS= Arsenic 45 '5, sulphur 19 '4, nickel 35 !, but varying much in composi- tion. Color sulphur- white to steel-gray. H. =5'5. G.=5'6-6 - 9. Ullmatmite or Nickel Stibine. An antimonial nickel sulphide, con- taining 25 to 28 per cent, of nickel. Color steel-gray, inclining to sil- ver-white. In cubical crystals, and also massive. H.=:5-5'5. G. =6'45. From the Duchy of Nassau. Grunauite or Bismuth Nickel. A sulphide containing 31 to 38*5 of sulphur, 10 to 14 per cent, of bismuth, with 22 to 40 '7 of nickel. Color light steel --gray to silver- white ; often tarnished yellowish. H. = 4-5. G. =5-13. From the district of Altenkirchen, Prussia. COBALT AND NICKEL. 167 Asbolite. Earthy Cobalt. Black Cobalt Oxide. Earthy, massive. Color black or blue-black. Soluble in muriatic acid, with an evolution of fumes of chlorine. Obs. Occurs in an earthy state mixed with oxide of man- ganese as a bog ore, or secondary product. Abundant at Mine La Motte, Missouri, and also near Silver Bluff, South Carolina. The analyses vary in the proportion of oxide of cobalt associated with the manganese, as the compound is a mere mixture. Sulphide of cobalt occurs with the oxide. The Carolina ores afforded Cobalt oxide 24, manganese oxide 76. The ore from Missouri, as analyzed by Prof. Silliman, afforded 40 per cent, of cobalt oxide, with oxides of nickel, manganese, iron and copper. This ore has been found abroad in France, Germany, Austria, and England. The ore is purified and made into smalt, for the arts. Erythrite. Cobalt Bloom. Hydrous Cobalt Arsenate. Monoclinic. In oblique crystals having a highly perfect cleavage, like mica ; laminae flexible in one direction. Also as an incrustation, and in reniform shapes, sometimes stel- late. Color, peach-red, crimson-red, rarely grayish or greenish ; streak a little paler, the dry powder lavender-blue. Lustre of laminae pearly ; earthy varieties without lustre. Trans- parent to subtranslu cent. H. 1 '5-2. G. = 2. 95. Composition. Co 3 8 As 2 + 8aq = Arsenic acid 38-4, oxide of cobalt 37 -6, water 24-6. B.B. on charcoal gives arsen- ical fumes and fuses ; yields a blue glass with borax. The earthy ore is sometimes called peach-blossom ore, from its color; and also red cobalt, ochre. Kottigite is a kind containing zinc. Diff. Eesembles red antimony, but that species wholly volatilizes before the blowpipe. From red copper ore it differs in giving a blue glass with borax ; moreover, the color of the copper ore is more sombre. Obs. Occurs with ores of lead and silver, and other co- balt ores. Schneeberg, in Saxony; Saalfield, in Thuringia ; and Riechelsdorf, in Hessia, are noted European localities. It is found also in Dauphiny, Cornwall, and Cumberland. Valuable as an ore of cobalt when abundant. 168 DESCRIPTIONS OF MINERALS. Roselite is a rose-red triclinic arsenate of cobalt. Bieberite or Cobalt Vitriol. Has a flesh-red or rose-red tint, and astringent taste. Co 4 S + 7aq = Sulphuric acid 28 '4, cobalt oxide 25'5, water 461. Morenosite. A nickel vitriol, Ni O 4 S + 7aq, having apple-green to greenish- white color. Lindackerite, hydrous nickel -copper arsenate. Zaratite or Emerald Nickel. Incrusting, minute globular or stalac- titic. Color bright emerald-green. Lustre vitreous. Transparent or nearly so. H. =;3-3'25. G. 2'5-2'7. It is a nickel carbonate, con- taining nearly 30 per cent, of water. B.B. infusible alone, but loses its color. Occurs with chromic iron and magnesium carbonate on serpentine, in Lancaster County, Pennsylvania. Remingtonite. A hydrous cobalt carbonate, rose-colored, from Finksburg, Md. Spherocobaltite. A cobalt carbonate, Co O 3 C, from Saxony. Nickel Silicates. Genthite is a hydrous magnesium and nickel sili- cate, of a pale apple-green color, yielding in one analysis 30 per cent, of nickel oxide. From Texas, Lancaster County, Pa., and other localities. Rottisite, from Rottis, Voigtland, is similar. Pimelite is an impure apple-green silicate, affording in one case 15 '6 per cent, of nickel oxide. Alipite is similar ; so also Oarnierite (and Noumeite), from New Caledonia, and worked there for nickel. General Remarks. The two arsenical ores of cobalt afford the greater part of the cobalt of commerce. The earthy oxide when abundant is a profitable source of the metal. Erythrite (Cobalt Bloom) occurs abundantly with other cobalt ores at its localities in Saxony, Thuringia and Hesse Cassel. Arsenopyrite (mispickel) yields at times 5 to 9 per cent, of cobalt. Cobalt is never employed in the arts in a metallic state, as its alloys are brittle and unimpor- tant. It is chiefly used for painting porcelain and pottery, and is required for this purpose in the state of an oxide, or the silicated oxide called smalt and azure. Zaffre is an impure oxide obtained in the calcining of the ore with twice its weight of sand; and from it the smalt and azure are produced. Nickel is worked in Germany, Austria, Russia, Sweden, England, United States, and New Caledonia. It is obtained largely from the copper nickel (niccolite) and chloan- thite, or from an artificial product called speiss (an impure arsenide), derived from roasting ores of cobalt containing nickel ; from siegenite (or nickel-linnaeite), a sulphide of cobalt and nickel ; from millerite), in part ; from the apple-green silicate ; and largely from pyrrhotite or "magnetic iron pyrites." At the Gap Mine, near Lancaster, Pa., the ore is millerite and pyrrhotite ; in Missouri, the siegenite ; in New Caledonia, chiefly the silicate. Nickel also occurs in meteoric iron, forming an alloy with the iron, which is characteristic of most meteorites. The proportion sometimes exceeds 20 per cent. As nickel does not rust or oxidize (except when heated), it is supe- rior to steel for the manufacture of many philosophical instruments. An alloy of copper, nickel, and zinc (one-sixth to one-third nickel), constitutes the German silver, or argentane. " German silver " is not a very recent discovery. In the reign of William III., an act was passed making it felony to Uanch copper in URANIUM. 1(59 imitation of silver, or mix it with silver for sale. " Wliite copper" has long been used in Saxony for various small articles ; the alloy employed is stated to consist of copper 88 '00, nickel 8 '75, sulphur with a little antimony 0'75, silex, clay, and iron 1*75. A similar alloy is well known in China, and is smuggled into various parts of the East Indies, where it is called packfong. It has been sometimes identified with the Chinese tutenague. M. Meurer analyzed the white copper of China, and found it to consist of copper 65*24, zinc 19 '52, nickel 13, silver 2 '5, with a trace of cobalt and iron. Dr. Fyfe ob- tained copper 40*4, nickel 31 '6, zinc 25'4, and iron 2 '6. It has the color of silver, and is remarkably sonorous. It is worth in China about one-fourth its weight of silver, and is not allowed to be carried out of the empire. An alloy of 88 per cent, copper and 12 per cent, nickel is the mate- rial of the United States cent, introduced in 1851. Switzerland, Bel- gium and Jamaica also have used a nickel alloy for coins. Nickel is mostly used at the present time for nickel-plating by electro deposition. The value of the metal in commerce rose in the years 1870 to 1875, from $1.25 to $3.00 per pound. The amount annually produced is about 600 tons. URANIUM. Uranium ores have a specific gravity not above 7, and a hardness below 6. The ores are either of some shade of light green or yellow, or they are dark brown or black and dull, or submetallic and without a metallic lustre when powdered. They are not reduced when heated with carbonate of soda ; and the brown or black species fuse with difficulty on the edges or not at all. Uraninite. Pitchblende. Uranium Oxide. Isometric. In octahedrons and related forms. Also mas- sive and botryoidal. Color grayish, brownish, or velvet- black. Lustre submetallic or dull. Streak black. Opaque. H.=5-5. G.=6-47. Composition. 75 to 87 per cent, of uranium oxides with silica, lead, iron, and some other impurities. Related to the spinel group. B.B. infusible alone ; a gray scoria with borax. Dissolves slowly in nitric acid, when powdered. Obs. Occurs in veins with ores of lead and silver in Saxony, Bohemia, and Hungary ; also in the tin mines of Cornwall, near Eedruth. In the United States, very spar- ingly at Middletown, Redding, and Haddam, Conn. ; in Nortb Carolina ; on the north side of Lake Superior (Coracite). 170 DESCRIPTIONS OF MINERALS. The oxides of uranium are used in painting upon porce- lain, yielding a fine orange in the enameling tire, and a black color in that in which the porcelain is baked. Cleveit?. Hydrated oxide of uranium, iron, erbium, cerium, yttrium, in cubic forms. From Norway. Oummite, An amorphous uranium ore, looking like gum, of a red- dish or brownish color. It is a hydrous uraninite, and has resulted from its alteration. Occurs at Johanngeorgenstadt, and in North Caro- lina. Eliasite. Another hydrous ore, more or less resin-like in aspect, of a reddish-brown to black color. Hatchettolite. A hydro as columbo-tantalate of uranium, in isome- tric octahedrons, resembling pyrochlore from North Carolina. G. = 4-76-4-84. Blomstrandite. A hydrous titano-columbate, from Sweden. Torbernite. Uranite. Chalcolite. Uran-Mica. Dimetric. In square tables, thinly foliated parallel to the base, almost like mica ; laminae brittle. Color emerald and grass-green ; streak a little paler. Lustre of laminae pearly. Transparent to subtranslucent. H. = 2-2-5. G.- 3 -4-3 -6. Composition. A uranium-copper phosphate, consisting if pure of Phosphorus pentoxide 15-1, uranium trioxide 61-3, copper oxide 8 '4, water 15-3 = 100. B.B. fuses to a blackish mass, and colors the flame green. Diff. The micaceous structure, connected with the bright green color and square tabular form of the crystals, are strik- ing characters. The folia of mica are not brittle, like those of uranite. Obs. Occurs with uranium, silver and tin ores. It is found at St. Symphorien, in splendid crystallizations, near Redruth and elsewhere in Cornwall ; in the Saxon and Bohemian mines ; in North Carolina. Autunite is similar to torbernite ; but has a bright citron-yellow color, and is a uranium-calcium phosphate. From the same mining ^regions, also from near Autun in France, and sparingly, from Portland, Middletown, and Redding, Conn.; Acworth, N. H. ; Chesterfield, Mass.; and in North Carolina. Uranospinite is an autunite containing arsenic instead of phos- phorus ; and Zeunerite is a torbernite containing arsenic instead of phosphorus. Samarskite (formerly named uranotantalite and yttroilmenite) is a compound of oxyd of uranium with columbic and tungstic acids, from Miask in the Ural. It is of a dark brown color and submetallic lustre. H=5'5. G.=5'4-5'7. Abundant in North Carolina. IRON. 171 Johannite or Uranmtriol is a sulphate of uranium. It has a fine emerald-green color, and a bitter taste. From Bohemia. Trdgerite and Walpurg&e are uranium ars f nates. Voglite and Liebigite are uranium carbonates. Johnnnite is a uranium vitriol ; Uranochalcitc , Medijdile, Zippeite, Voglianite, Uraconite, are other uranium sulphates. Uranocircite is a hydrous barium-uranium phosphate. IRON. Iron occurs native, and alloyed with nickel in meteoric iron. Its most abundant ores are the oxides and sulphides. It is also found combined with arsenic, forming arsenides and sulpharsenides ; with oxygen and other metals, as chro- mium, aluminum, magnesium ; and in the condition of sul- phate, phosphate, arsenate, columbate, silicate and carbon- ate, of which the last is an abundant and valuable ore. Its ores are widely disseminated. The oxides and silicates are the ordinary coloring ingredients of soils, clays, earth and many rocks, tinging them red, yellow, dull green, brown, and black. The ores have a specific gravity below 8, and the ordinary workable ores seldom exceed 5. Many of them are infusible before the blowpipe, and nearly all minerals containing iron become attractable by the magnet after heating, when not so before. By their difficult fusibility, the species with a metallic lustre are distinguished from ores of silver and cop- per, and also more decidedly from these and other ores by blowpipe reaction. Native Iron. Isometric. Usually massive with octahedral cleavage. Color and streak iron-gray. Fracture hackly. Malleable and ductile. H. =4 -5. G. =7 -3-7 -8. Acts strongly on the magnet. Obs. Native iron occurs in grains disseminated through some doleryte, basalt, and other related igneous rocks ; and in Greenland, in very large masses in such igneous rocks, the largest weighing over a ton. It is suggested by J. Lawrence Smith, that the iron was reduced "by means of carbohydrogen vapors, taken into the rock from carbonaceous rocks passed through on the way to the surface. 172 DESCRIPTIONS OP MINERALS. It is a constituent of nearly all meteorites, and the chief ingredient in a large part of them ; and in this state it is with a rare exception alloyed with nickel, and with traces of cobalt and copper. The Texas meteorite, of Yale College, weighs 1,635 pounds ; the Pallas meteorite, now at Vienna, originally 1,600 ; but one in Mexico, the San Gregorio meteorite, is stated to weigh five tons ; and one in the dis- trict of Chaco-Gualamba, S. A., nearly fifteen tons. Meteoric iron often has a very broad crystalline structure, long lines and triangular figures being developed by putting nitric acid on a polished surface. The coarseness of this structure dif- fers in different meteorites, and serves to distinguish speci- mens not identical in origin. Nodules of troilite (FeS), and schreibersite (iron phosphide) are common in iron me- teorites. Meteoric iron may be worked like ordinary malle- able iron. The nickel diminishes the tendency to rust. But some kinds contain iron chloride, or are open in texture, and rust badly. Pyrite. Iron Pyrites. Iron Bisulphide. Isometric. Usually in cubes, the strise of one face at right angles with those of either adjoining face, as in fig. 1. Also IRON. 173 figs. 2 to 7 ; also figs. 8 to 15 on page 6. Fig. 6, a pentag- onal dodecahedron, is a common form. Occurs also in imi- tative shapes, and massive. Color brass-yellow ; streak brownish black. Lustre of crystals often splendent metallic. Brittle. H. = 6-6-5, be- ing hard enough to strike fire with steel. G. =4: -8-5-1. Composition. Fe S 2 Sulphur 53-3, iron 46-7 = 100. B.B. on charcoal gives off sulphur, and ultimately affords a globule attractable by the magnet. Pyrite often contains a minute quantity of gold, and is then called auriferous pyrite. See under Gold. Nickel, cobalt and copper occur in some pyrite. Diff. Distinguished from copper pyrites in being too hard to be cut by a knife, and also in its paler color. The ores of silver, at all resembling pyrite, instead of having its pale bronze-yellow color, are steel-gray or nearly black ; and be- sides, they are easily scratched with a knife and quite fusible. Gold is sectile and malleable. Obs. Pyrite is one of the most common ores on the globe. It occurs in rocks of all ages. Cornwall, Elba, Piedmont, Sweden, Brazil, and Peru, have afforded magnifi- cent crystals. Alston Moor, Derbyshire, Kongsberg in Nor- way, are well-known localities. It has also been observed in the Vesuvian lavas, and in many other igneous rocks. In the United States, the localities are numerous. Fine crystals have been met with at Eossie, N. Y. ; at many other places in that State ; also in each of the New England States and in Canada ; in New Jersey, Pennsylvania, Vir- ginia, North Carolina, Georgia, in Colorado, Wyoming and the States west. It occurs in all gold regions, and is one source of gold. This species is of the highest importance in the arts, although not affording good iron on account of the diffi- culty of separating entirely the sulphur. It affords the greater part of the sulphate pf iron (green vitriol or copperas) and sulphuric acid (oil of vitriol) of commerce, and also a considerable portion of the sulphur and alum. To make the sulphate the pyrites is sometimes heated in clay retorts, by which about 17 "per cent, of sulphur is distilled over and collected. The ore is then thrown out into heaps, exposed to the atmosphere, when a change ensues by which the re- maining sulphur and iron become through oxidation sul- phate of iron. The material is lixiviated, and partially eva- 174 DESCRIPTIONS OF MINERALS. porated, preparatory to its being run off into vats or troughs to crystallize. In other instances, the ore is coarsely broken up and piled in heaps and moistened. Fuel is sometimes used to commence the process, which afterwards the heat generated continues. Decomposition takes place as before, with the same result. Cabinet specimens of pyrite, espe- cially granular or amorphous masses, often undergo a spon- taneous change to the sulphate, particularly when the atmo- sphere is moist. Pyrite, owing to its tendency to oxidation, and its very general distribution in rocks of all kinds and ages, is one of the chief sources of the disintegration and destruction of rocks. No granite, sandstone, slate, or limestone, contain- ing it, is fit for architectural purposes or for any outdoor uses. The same destructive effects come from pyrrhotite and marcasite, which also are widely diffused. The name pyrites is from the Greek pur, fire, because, as Pliny states, "there was much fire in it," alluding to its striking fire with steel. Thi.3 ore is the mundic of miners. Marcasite or White iron pyrites. This ore has the same composition as pyrites, but differs in crystallizing in trimetic forms. /A/=106 36 . The color is a little paler than that of pyrite, and it is more liable to decomposition ; hardness the same ; specific gravity 4'6-4'85. Radi- ated pyrites, Hepatic pyrites, Cockscomb pyrites (alluding to its crested shapes;, and Spear pyrites, are names of some of its varieties. It oc- curs in crystals at Warwick and Phillipstown, N. Y. Massive varie- ties are met with at Cummington, Mass.; Monroe, Trumbull, and East Haddam, Conn. ; and at Haverhill, N. H. Pyrrhotite. Magnetic Pyrites. Iron Sulphide. Hexagonal. Occurs occasionally in hexagonal prisms, which are often tabular ; generally missive. Color between bronze-yellow and copper-red ; streak dark grayish-black. Brittle. H. =3-5 -4-5. G.=44-4;65. Slightly attracted by the magnet. Liable to speedy tarnish. Composition. Fe 7 S 8 =: Sulphur 39-5, iron 60-5. It is often a valuable ore of nickel, containing sometimes 3 to 5 per cent, of this metal. B.B. on charcoal in the outer flame it is converted into red oxide of iron. In the inner flame it fuses and glows, and affords a black globule which is magnetic, and has a yellowish color on a surface of frac- ture. Diff. Its inferior hardness and shade of color, and its IRON. 175 magnetic quality distinguish it from pyrite ; and its pale- ness of color from chalcopyrite or copper pyrites. Obs. Crystallized specimens have been found at Kongs- berg in Norway, and at Andreasberg in the Hartz. The massive variety is found in Cornwall, Saxony, Siberia, and the Hartz ; also at Vesuvius and in meteoric stones. In the United States, it is met with at Trumbull and Monroe, New Fairfield, and Litchfield, Conn. ; at Straff ord and Shrewsbury, Vt. ; at Corinth, New Hampshire; in many parts of Massachusetts and New York ; at Lancaster, Pa., where it is worked for nickel. It is used for making green vitriol and sulphuric acid, like pyrite. Troilite is a similar mineral of the formula Fe S, occur- ring in meteorites. Schreibersite is a phosphide of iron and nickel, occurring in meteorites. Arsenopyrite. Mispickel. Arsenical Iron Pyrites. Trimetric. In rhombic prisms, with cleavage parallel to the faces /; /A/=lll 40' to 112. Crystals sometimes elongated horizon- tally, producing a rhombic prism of 100 nearly, with / and / the end planes. Occurs also massive. Color silver-white ; streak dark grayish-black. Lustre shining. Brit- tle. H.=5-5-G. G.=6-3. Composition. Fe AsS Arsenic 46 -0, sulphur 19-6, iron 34-4=100. A co- baltic variety contains 4 to 9 per cent, of cobalt in place of part of the iron ; Danaite of New Hampshire, consists of Arsenic 41-4, sulphur 17-8, iron 32-9, cobalt 6-5. B.B. affords arsenical fumes, and a globule of iron sulphide which is attracted by the magnet. In the closed tube a sublimate of arsenic sulphide. Gives fire with a steel and emits a garlic odor. Diff. Eesembles arsenical cobalt, but is much harder, it giving fire with steel; it differs also in yielding a mag- netic globule before the blowpipe, and in not affording the reaction of cobalt with the fluxes. Obs. Arsenopyrite is found mostly in crystalline rocks, and is commonly associated with ores of silver, lead, iron, or cop- per. It is abundant at Freiberg, Munzig, and elsewhere in Europe, and also in Cornwall, England. 176 DESCRIPTIONS OF MINERALS. It occurs in crystals in New Hampshire, at Franconia, Jackson, and Haverhill ; in Maine, at Blue Hill Bay, Corinth, Newfield, and Thomaston ; in Vermont, at Waterbury ; in Massachusetts, massive at Worcester and Sterling ; in Con- necticut, at Chatham, Derby, and Monroe ; in New Jersey, at Franklin ; in New York, in Lewis, Essex County, and near Edenville and elsewhere in Orange County ; in Kent, Putnam County. Leucopyrite. This is the name of arsenical iron Fe 2 As 3 . It re- sembles the preceding in color and in its crystals. I f\ 7=122 20'. It has less hardness and higher specific gravity. H. =5-5*5. G. =7'2 -7 '4. Contains Iron 32 '2, arsenic GO '9, with some sulphur. From Styria, Silesia, and Carinthia. Lollingite is another iron arsenide, Fe As.2=Arsenic 72'8, iron 27'2 ; specific gravity 6 '8-8 '71. Berthierite is an iron sulphantimonite. Hematite. Specular Iron Ore. Iron Sesquioxide. Khombohedral. In complex modifications of a rhombohe- 3. dron of 86 10' (fig. 1); crystals occasionally thin tabular. Cleavage usually indistinct. Often massive granular ; some- times lamellar or micaceous. Also pulverulent and earthy. Color dark steel-gray or iron-black, and often when crys- tallized having a highly splendent lustre ; streak-powder cherry-red or reddish -brown. The metallic varieties pass into an earthy ore of a red color, having none of the external characters of the crystals, but perfectly corresponding to them when they are pulverized, the powder they yield being of a deep red color, and earthy or without lustre. Gr. =4-5-5 -3. Hardness of crystals 5 -5-6 -5. Sometimes slightly attracted by the magnet. VARIETIES. Specular iron. Having a perfectly metallic lustre. Micaceous iron. Structure foliated. Red hematite. Submetallic, or unmetallic, and of a brown- ish-red color. Red ochre. Soft and earthy, and often containing clay. IRON. 177 Red chalk. More firm and compact than red ochre, and of a fine texture. Jasper y clay iron. A ha1*d impure siliceous clayey ore, and having a brownish-red jaspery look and compactness. Clay iron stone. The same as the last, the oolor and ap- pearance less like jasper. But this is one variety only of what is called "clay iron stone," a name covering also a re- lated variety of siderite and limonite. Lenticular argillaceous ore. A red ore, consisting of small flattened grains. Martite is hematite in octahedrons, derived, it is supposed, from the oxidation of magnetite. Composition. Fe0 3 = Oxygen 30, iron 70 = 100. B.B. alone infusible. Heated in the inner flame it becomes strongly magnetic. Diff. The red powder of this mineral, and the magnetism which is so easily induced in it by a reduction flame dis- tinguish hematite from all other ores. The word hematite, from the Greek haima, blood, alludes to the color of the powder. Obs. This ore occurs in crystalline and stratified rocks of all ages. The more extensive beds of pure ore abound in Archaean rocks ; while the argillaceous varieties occur in stratified rocks, being often abundant in coal regions and among other strata. Crystallized specimens are found also in some lavas, as a volcanic product. Splendid crystallizations of this ore come from Elba, whose beds were known to the Romans ; also from St. Gothard ; Arendal, Norway ; Longbanshyttan, Sweden ; Lorraine and Dauphiny. Etna and Vesuvius afford handsome specimens. In the "United States, this is an abundant ore. The two Iron Mountains of Missouri, situated 90 miles south of St. Louis, consist mainly of this ore, piled " in masses of all sizes from a pigeon's egg to a middle-are church." One of them is 300 feet high, and the other, the "Pilot Knob," is 700 feet. The massive and micaceous varieties occur there together with red ochreous ore. Large beds occur in Essex, St. Lawrence and Jefferson counties, N. Y., and at Mar- quette, in Michigan; the micaceous variety, at Hawley, Mass., Piermont, N. H., and in Stafford County, Va.; lenticular argillaceous ore abundantly in Oneida, Herkimer, Madison and Wayne counties, N. Y., constituting one or two beds of the Clinton group (tipper Silurian), in a compact sandstone ; 178 DESCRIPTIONS OF MINERALS. and the same is found in Pennsylvania and south to Alabama, and also in Wisconsin ; it contains 50 per cent, of oxide of iron, with about 25 of carbonate of lime and more or less magnesia and clay. The coal region of Pennsylvania affords abundantly the clay iron ores, but they are mostly either the argillaceous carbonate or limonite. Valuable as an iron ore, though less easily worked when pure and metallic than the magnetic and hydrous ores. Pul- verized red hematite is used for polishing metal. Eed chalk is a well-known material for red pencils. Menaccanite. Ilmenite. Titanic Iron. Washingtonite. Ehombohedral. 72A72-S5 31'. Often in thin plates or seams in quartz ; also in grains. Crystals sometimes very large and tabular. Color iron-black ; streak submetallic. Lustre metallic or submetallic. H. =5-6. G. =4'5-5. Acts slightly on the magnetic needle. Composition. Like that of hematite, except that part of the iron is replaced by titanium ; the amount replaced is very variable. Infusible alone before the blowpipe. Diff. Near specular iron, bat its powder is not red. Obs. Crystals, an inch or so in diameter, occur in War- wick, Amity and Monroe, Orange County, N. Y. ; also near Edenville and Greenwood Furnace ; also at South Royalston and Goshen, Mass. ; at Washington, South Britain, and Litchfield, Conn. ; at Westerly, Rhode Island. * It is of no value in the arts and is a deleterious constitu- ent of many iron ores. Magnetite. Magnetic Iron Ore. Isometric. Often in octahedrons (fig. 1), and dodecahe- drons (fig. 2 ). Cleavage octahe- g dral ; sometimes distinct. Also granularly massive. Occasionally in dendritic forms between the folia of mica. Col or iron-black. Streak black. Brittle. II. 5*5-6-5. G.=--5'0 -5*1. Strongly attracted by the magnet, and sometimes having polarity. Composition. Fee0 4 =:FeO-f Ee0 3 = Oxygen 27'6, iron IRON. 179 72-4=100. Infusible before the blowpipe. Yields a yellow glass when fused with borax in the outer flame. Diff. The black streak and strong magnetism distinguish this species from the following. Obs. Magnetic iron ore occurs in extensive beds, and also in disseminated crystals. It is met with in granite, gneiss, mica schist, clay slate, syenyte, hornblende and chlorite schist ; and also sometimes in limestone. The beds at Arendal, and nearly all the Swedish iron ore, consist of massive magnetic iron. At Dannemora and the Taberg in Southern Sweden, and also in Lapland at Kurun- avara and Gelivara, there are mountains composed of it. In the United States it constitutes extensive beds, in Ar- chaean rocks, in Warren, Essex, Clinton, Orange, Putnam, Saratoga and Herkimer counties, New York; and in Sussex and Warren counties, in New Jersey. Smaller deposits occur in the several New England States and Canada. Also found at Magnet Cove, in Arkansas ; in California, in Sierra County, and elsewhere. It exists with hematite in the Iron Mountains of Missouri. Masses of this ore, in a state of magnetic polarity, consti- tute what are called lodestones or native magnets. They are met with in many beds of the ore. Siberia and the Hartz have afforded fine specimens ; also the Island of Elba. They also occur at Marshall's Island, Maine; also near Providence, Rhode Island, and at Magnet Cove, in Arkansas. The lodestone is called magnes by Pliny, from the name of the country, Magnesia (a province of ancient Lydia), where it was found ; and it hence gave the terms magnet and mag- netism to science. Franklinite. Isometric. In octahedral and dodecahedral crystals. Also coarse granular massive. Color iron-black ; streak dark reddish-brown. Brittle. H.^5'5-6'5. G. =4-85-51. Usually is attracted by the magnet. Composition. General formula like that of magnetite, RE 4 , but having zinc and manganese replacing part of the iron, as indicated in the formula (Fe, Zn, Mn) (fee,Mn)0 4 . A common variety corresponds to Fe s 3 G7'6, Fe 5 '8, Zn O 6-9, MnO 9-7=100. B.B. with soda on charcoal a zinc coating is obtained ; a 180 DESCRIPTIONS OP MINERALS. soda bead in the outer flame is colored green by the manga- nese. Diff. Resembles magnetic iron, but the exterior color is a more decided black. The streak is reddish brown, and the blowpipe reactions are distinctive. Obs. This is an abundant ore at Sterling and Hamburg, in New Jersey, near the Franklin Furnace ; at the former place the crystals are sometimes four inches in diameter ; also amorphous at Altenberg, near Aix-la-Chapelle. Chromite. Chromic Iron. Isometric. In octahedral crystals, without distinct cleav- age. Usually massive, and breaking with a rough unpolished surface. Color iron-black and brownish black ; streak dark brown. Lustre submetallic ; often faint. H. =5-5. G. =4*3-4-6. In small fragments attractable by the magnet. Composition. General formula RR 4 , as for magnetite ; but part of the iron is replaced by chromium. Analysis gives Iron protoxide 32, chromium sesquioxide 68 = 100; aluminum and magnesium also are commonly present in variable amounts, replacing the other constituents. B. B. infusible alone ; with borax a beautiful green bead. This ore usually possesses a less metallic lustre than the other black iron ores. Obs. Occurs usually in serpentine rocks, in imbedded masses or veins. Some of the foreign localities are the Gulsen Mountains in Styria ; the Shetland Islands ; the de- partment of Var in France ; Silesia, Bohemia, etc. In the United States it is abundant : in Maryland in the Bare Hills, near Baltimore, and also in Montgomery County, at Cooptown, in Harford County ; and in the north part of Cecil County ; occurs also in Townsend and Westfield, Ver- mont, and at Chester and Blandford, Mass. It is also found in Pennsylvania, at Wood's Mine, near Texas, Lancaster County, in West Branford, Chester County ; at Bolton and Ham, Canada East ; in California near New Idria ; also in Sonoma County ; Tuolumne County, near Crimea House, and elsewhere ; at Seattle in Wyoming. The compounds of chromium, which are extensively used as pigments, are obtained chiefly from this ore. Meteorites have afforded a chromium-sulphide, named Daubreelite. IRON. 181 Limonite. Brown Hematite. Usually massive, and often with a smooth botryoidal or stalactitic surface, having a compact fibrous structure with- in. Also earthy. Color dark brown and black to ochre-yellow ; streak yellow- ish brown to dull yellow. Lustre sometimes submetallic ; often dull and earthy ; on a surface of fracture frequently silky. H.=5-5-5. G.=3'6-4. The following are the principal varieties : Brown hematite. The botryoidal, stalactitic and asso- ciated compact ore. Brown ochre, Yelloiv ochre. Earthy ochreous varieties, of a brown or yellow color. Brown and Yellow day iron stone. Impure ore, bard and compact, of a brown or yellow color. Bog iron ore. A loose earthy ore of a brownish-black color, occurring in low grounds. Composition. Ee 9 H 6 ( = 2 Fe 3 + 3 H 2 0) Iron sesqui- oxide 85-6, water 14-4-100; or it is a hydrous iron ses- quioxide, containing, when pure, about two-thirds its weight of pure iron. B.B. blackens and becomes magnetic; with borax in the outer flame a yellow glass. Diff. This is a much softer ore than either of the two preceding, and is peculiar in its frequent stalactitic forms, and in its affording water when heated in a glass tube. Obs. Occurs connected with rocks of all ages, but ap- pears, as shown by the stalactitic and other forms, to have resulted in all cases from the decomposition of other iron ores. An abundant ore in the United States. Extensive beds exist in Salisbury and Kent, Conn. , also in the neighboring towns of Beekman, Fishkill, Dover, Amenia, X. Y.; also in a similar situation north, in Richmond and West Stock- bridge, Mass. ; also in Bennington, Monkton, Pittsford, Putney, and Ripton, Vermont. *" Large beds are found in Pennsylvania, the Carolinas, near the Missouri Iron Moun- tains, and also in Tennessee, Iowa and Wisconsin. This is one of the most valuable ores of iron. The limo- nite of Western New England, and that along the same range geologically in Dutchess County, New York, Eastern Pennsylvania, and beyond, is remarkably free from phos- phorus, and hence is highly valued for its iron. Bog orea 182 DESCRIPTIONS OF MINERALS. usually contain much phosphorus, from organic sources, and hence the iron afforded is best fitted for castings. Li- monite is also pulverized and used for polishing metallic buttons and other articles. As yellow ochre, it is a common material for paint. Gothite (Pyrrlwsidcrite, Lepidokrokite) is another iron hydrate, often in prismatic crystals, as well as fibrous and massive, of the formula Fe O 4 H 2 ( = Ee O 3 + H, O), and G. = 4 -0-4 -4: Turgite has the formula EeO 7 H a =2EeO 3 + H 2 0. Xantho#iderit& and limnite are other related hydrates. Melanterite. Copperas. Iron Vitriol. Green Vitriol. Monoclinic. In acute oblique rhombic prisms. / A /= 82 21'; A 7= 80 37'. Cleavage parallel to perfect. Generally pulverulent or massive. Color greenish to white. Lustre vitreous. Subtranspa- rent to translucent. Taste astringent, sweetish, and metal- lic. Brittle. H.=2. G.=l-83. Composition. Fe 4 S 4- 7aq= Sulphur trioxide 28-8, iron protoxide 25-9, water 45-3 = 100. B.B. becomes magnetic. Yields glass with borax. On exposure, becomes covered with a yellowish powder, which results from oxidation. Obs. This species is the result of the decomposition of pyrite and pyrrhotite, which readily afford it if moistened while exposed to the atmosphere, and it is obtained from these sulphides for the arts (p. 173). An old mine near Goslar, in the Hartz, is a noted locality. Copperas is much used by dyers and tanners, on account of its giving a black color with tannic acid, an ingredient in nutgalls and many kinds of bark. It for the same reason forms the basis of ordinary ink, which is essentially an in- fusion of nutgalls and copperas. It is also employed in the manufacture of Prussian blue. With potassium ferrocya- nide, any soluble salt of iron sesquioxicle, even in minute quantity, gives a fine blue color to the solution (due to the formation of Prussian blue), and this is a delicate test of the presence of iron. CoquimUte, Copiaptte, Voltaitt, Raimondite, Botryogeri, Fibroferrite, Ihleite, are names of other hydrous iron sulphates ; and Halotrichite is an iron-alum. Jarosite is a hydrous iron-potash sulphate. Pisanite is an iron-copper vitriol. Lagonite. A hydrous iron borate, from the Tuscan lagoons. IRON. 183 Wolframite. Wolfram. Iron-Manganese Tungstate. Monoclinic. Sometimes pseudomorphous in octahedrons formed by the alteration of tungstate of lime. Also massive. Color dark grayish-blaok ; streak dark reddish-brown. Lustre submetallic, shining, or dull. H. =5-5*5. G. = 7-1-7-5. Composition. (Fe,Mn)0 4 W. A typical variety affords tungsten trioxide 76*47, iron protoxide 9*49, manganese protoxide 14*04=100. A manganese wolframite has been named Hiibnerite. B.B. fuses easily to a magnetic globule ; with aqua regia dissolved with the separation of yellow tungsten trioxide. Found often with tin ores. Occurs in Cornwall, and at Zinnwald and elsewhere in Europe. In the United States it is found at Monroe and Trumbull, Conn. ; on Camdage Farm, near Blue Hill Bay, Me. ; near Mine la Motte, Mis- souri ; in the gold regions of North Carolina ; in Mammoth Mining district, Nevada Hiibnerite. Columbite. Trimetric. In rectangular prisms, more or less modified. Also massive. Cleavage parallel to the lateral faces of the prism, some- what distinct. Color iron-black, brownish-black ; often with a characteristic iridescence on a surface of fracture ; streak dark brown, slightly reddish. Lustre sub- metallic, shining. Opaque. Brittle. H.=r5-G. G.=o-4-6-5. Composition. Iron columbate, of the formula F 6 Cb. 2 = Columbium pentoxide 79'G, iron protoxide 16'4, manganese protoxide 4'4, tin oxide 0'5, lead and copper oxides 0*1 = 100. Tantalum often replaces part of the columbium, and in this case the mineral is of higher speci- fic gravity. B.B. alone infusible. It imparts to the borax bead the yellow color of iron. Diff. Its dark color, submetallic lustre, and a slight iri- descence, together with its breaking readily into angular fragments, will generally distinguish this species from the ores it resembles. 184 DESCRIPTIONS OP MINERALS. Ols. Occurs in granite at Bodenmais in Bavaria, and also in Bohemia. In the United States, it is found in gra- nitic veins, at Middletown and Haddam, Conn. ; at Ches- terfield and Beverly, Mass. ; at Ac worth, N. H. ; Green- field, N. Y. A crystal was found at Middletown, which originally weighed 14 pounds avoirdupois ; and a part of it, 6 inches in length and breadth, weighing 6 Ibs. 12 oz., is now in the collections of the Wesleyan University of that place. Also at Standisb, Maine ; and in granite veins in North Carolina. This mineral was first made known from American speci- mens, by Mr. Hatchett, an English chemist, and the new metal it was found to contain was named by him columbium. Tantalite. Fe(Mn) O 6 Ta 2 . This tantalate of iron is allied to colum- bite. H. 6-6 '5. G. 7-8. It is distinguished by its higher specific gravity. It sometimes contains tin and tungsten. From Finland, Sweden, near Limoges in France, and from North Carolina and Alabama. Note. The metal named Columbium by Hatchett, is the same that has since been called Niobium, without any good reason for the change of name. Triphylite. An iron manganese-lithium phosphate. See p. 190. Vivianite. Hydrous Iron Phosphate. Monoclinic. In modified oblique prisms, with cleavage in one direction highly perfect. Also radiated, reniform, and globular, or as coatings. Color deep blue to green. Crystals usually green at right angles with the vertical axis, and blue parallel to it. Streak bluish. Lustre pearly to vitreous. Transparent to translu- cent ; opaque on exposure. Thin laminae flexible. H. = 1-5-2. G.=2'66. Composition. Pe 3 8 P 2 + 8aq = Phosphorus pentoxide, 28-3, iron protoxide 43-0, water 28-7 = 100. B.B. fuses easily to a magnetic globule, coloring the flame greenish blue. Affords water in a glass tube, and dissolves in hydro- chloric acid. Diff. The deep blue color and the little hardness are decisive characteristics. The blowpipe affords confirma- tory tests. Obs. Found with iron, copper and tin ores, and some- times in clay, or with bog iron ore. St. Agnes in Cornwall, Bodenmais, and the gold mines of Vorospatak in Transylva- nia, afford fine crystallizations. In the United States, good IRON. 185 crystals have been found at Imlaystown, N. J. At Allentown, Monmonth County, and Mullica Hill, Gloucester County, N. J., are other localities. It often fills the interior of certain fossils. Occurs also at Harlem, N. Y., in Somerset and Worcester counties, Md., and with bog ore in Stafford County, Va. Abundant at Vandreuil in Canada, where it is associated with limonitc. The blue iron earth is an earthy variety, containing about 30 per cent, of phosphoric acid. Ludlamite. A clear green hydrous phosphate of iron in monoclinic crystals ; from Cornwall. Dufrenite. A hydrous phosphate of iron sesquioxide. It has a dull green color, and is often found in radiated forms. Cacoxenite. Occurs in radiated silky tufts of a yellow or yellow- ish-brown color. H. = 3-4. G.=3 P 38. It is a phosphate of iron sesquioxide, and often contains alumina. It differs from wavellite, which it resembles, in its more yellow color and iron reactions. It also resembles carpholite, but has a deeper color, and does not give the manganese reactions. It occurs on brown iron ore in Bohemia. Clialcosideritc, and Andrewsite are other iron phosphates. Strengite. A hydrous iron phosphate related in formula to scoro- dite. From near Giessen. Ar senates of Iron. Pharmacosiderite, or Cube ore. Occurs in cubes of dark green to brown and red colors. Lustre adamantine, not very distinct. Streak greenish or brownisTi. H.=2'5. G. =3. It is a hydrous arsenate of iron sesquioxide, containing 43 per cent, of arsenic pentoxide. From the Cornwall mines ; also from France and Saxony. Scorodite. Crystallizes in rhombic prisms, with an angle of 120 10' between its secondary prismatic planes. Color pale leek -green or liver brown. Streak uncolored. Lustre vitreous to subadamantine. Sub- transparent to nearly opaque. H. = 3*5-4. G. =3'l-3'3. A hydrous arsenate of iron sesquioxide, containing 50 per cent, of arsenic pen- toxide. From Saxony, Carinthia, Cornwall, and Brazil ; and minute crystals near Edenville, N. Y., with arsenical pyrites. The name of this species is from the Greek skorodon, garlic, alluding to the odor before the blowpipe. Iron sinter is an amorphous form of the same mineral. Arseniosidcrite is another iron arsenate. Siderite. Spathic Iron. Iron Carbonate. Ehombohedral. In rhombohedrons with easy cleavage parallel to a rhombohedron of 107. Faces often curved. Usually massive, with a foliated struc- ture, somewhat curving. Sometimes in globular concretions or implanted globules. Color light grayish to brown; often dark brownish -red. It becomes nearly black on ex- 186 DESCRIPTIONS OF MINERALS. posure. Streak tincolored. Lustre pearly to vitreous. Trans* lucent to nearly opaque. H. =3-4-5. G. =3-7-3-9. Composition. Fe 3 C = Carbon dioxide 3 7 -9, iron protox- ide 62-1 = 100. Often contains some manganese oxide 01 magnesia, and lime replacing part of the iron protoxide. Before the blowpipe it blackens and becomes magnetic ; but alone it is infusible. Dissolves in heated hydrochloric acid With effervescence. The ordinary crystallized 01 foliated variety is called spathic or sparry iron, because the mineral has the aspect of a spar. The globular concretions found in some amygda- loidal rocks have been called splierosiderite because of its spheroidal forms. An argillaceous variety occurring in nod- ular forms is often called clay iron stone, and is abundant in coal measures. Diff. This mineral cleaves like calcite and dolomite, but it has a much higher specific gravity. It readily becomes magnetic before the blowpipe. Heated in a closed glass tube it gives off carbon dioxide, and becomes magnetic. This test distinguishes it from other iron ores. Obs. Spathic iron occurs in rocks of various ages, and often accompanies metallic ores. The largest deposits are in gneiss and mica schist, and clay slate. It is also abundant in the coal formation principally in the form of clay iron stone. In Styria and Carinthia, it is very abundant in gneiss, and in the Hartz it occurs in graywacke. Cornwall, Alston- moor, and Devonshire are English localities. A vein of considerable extent occurs at Roxbury, near New Milford, Conn., in quartz, traversing gneiss; "at Ply- mouth, Vt., and Sterling, Mass., it is also abundant. It oc- curs also at Monroe, Conn. ; in New York State, in Antwerp, Jefferson County, and in Hermon, St. Lawrence County. The argillaceous carbonate in nodules and beds, is very abundant in the coal regions of Pennsylvania and the West. This ore is employed extensively for the manufacture of iron and steeL Mesitite is an iron-and-magnesium carbonate. Ankerite contains in addition a large percentage of calcium. Like siderite in crystalliza- tion and cleavage. General Remarks. The metal iron has been known from the most remote historical period, but was little used until the last centuries be- fore the Christian era. Bronze, an alloy of copper and tin, was the almost universal substitute, for cutting instruments as well as weapons IRON. 187 of war, among the ancient Egyptians and earlier Greeks ; and even among the Romans (as proved by the relics from Pompeii), and also throughout Europe, it continued long to be extensively employed for these purposes. The Chalybes, bordering on the Black Sea, were workers in iron and steel at au early period ; and near the year 500 B.C., this metal was introduced from that region into Greece, so as to become common for weapons of war. From this source we have the expression chalybeate applied to certain substances or waters containing iron. The iron mines of Spain have also been known from a remote epoch, and it is supposed that they have been worked " at least ever since the times of the later Jewish kings ; first by the Tyrians, next by the Carthaginians, then by the Romans, and lastly by the natives of the country." These mines are mostly contained in the present provinces of New Castile and Aragon. Elba was another region of ancient works, "inexhaustible in its iron," as Pliny states, who enters somewhat fully into the modes of manufacture. The mines are said to have yielded iron since the time of Alexander of Macedon. The ore beds of Styria in Lower Austria, were also a source of iron to the Romans. The ores from which the iron of commerce is obtained, are the spathic iron or carbonate, magnetic iron, hematite or specular iron, limonite or "brown hematite," and bog iron ore. In England, the prin- cipal ore used is an argillaceous carbonate of iron, called often clay iron stone, found in nodules and layers in the coal measures. It con- sists of carbonate of iron, with some clay, and externally has an earthy, stony look, with little indication of the iron it contains except in its weight. It yields from 20 to 35 per cent, of cast iron. The coal basin of South Wales, and the counties of Stafford, Salop, York, and Derby, yield by far the greater part of the English iron. Brown hematite is also extensively worked. In Sweden and Norway, at the famous works of Dannemora and Arcndal, the ore is the magnetic iron ore, and is nearly free from impurities as it is quarried out. It yields 50 to 60 per cent, of iron. The same ore is worked in Russia, where it abounds in the TJrals. The Elba ore is the specular iron. In Germany, Styria, and Carinthia, extensive beds of the spathic iron are worked. The bog ore is largely reduced in Prussia. In the United States, all these different ores are worked. The local- ities are already mentioned. The magnetic ore is reduced in New England, New York, Northern New Jersey, and sparingly in Pennsyl- vania, and other States. Limonite, or brown hematite, is largely worked along Western New England and Eastern New York, in Penn- sylvania, and many States South and West. The earthy argillaceous carbonate like that of England, and the hydrate, are found with the coal deposits, and are a source of much iron. The amount of iron manufactured in the world in the year 1873 was 14,835,488 tons, of which Great Britain produced 6,566,000 tons, United States, 2,561,000 tons, Germany 1,665,000 tons, France 1,331,000 tons, Belgium 653,000 tons, Austria with Hungary 425,000 tons, Russia 354,000 tons, Sweden 322,000 tons, Luxembourg 300,000 tons. 188 DESCRIPTIONS OF MINERALS. MANGANESE. The common ores of manganese are the oxides, the car- bonate, and the silicates. There are also sulphides, an arsenide, and phosphate. They haye a specific gravity be- low 5 -2. Manganese Sulphides and Arsenide, Aldbandite or Mangariblende. A manganese sulphide Mn S, of an iron-black color, green streak, submetallic lustre. H. =8*5-4 G. 3*9-4'0. Crystals, cubes and regular octahedrons. From the gold mines of Nagyag, in Transylvania. Hauerite. A sulphide, Mn S 1 ', containing twice the proportion of sulphur in the last. Color reddish brown and brownish black, re- sembling blende. H. =4. Gr. 3*46. From Hungary. Kaneite is a manganese arsenide, of a grayish-white color, and metallic lustre, which gives off alliaceous fumes. G.=5'55. From Saxony. Pyrolusite. Manganese Dioxide. Trimetric. In small rectangular prisms, more or less modified. /A/ 93 40'. Sometimes fibrous and radiated or divergent. Of- ten massive and in reniform coatings. Color iron-black ; streak black, non- metallic. H. 2-2-5 G. = 4-8. Composition. Mn 2 = Manganese 63-2, oxygen 36 -8^100. A minute portion of it imparts to a borax bead a deep amethystine color while hot, which becomes red-brown on cooling. It yields no water in a matrass. Diff. Differs from psilomelane by its inferior hardness, and from ores of iron by the violet glass with borax. Obs. This ore is extensively worked in Thuringia, Mo- ravia, and Prussia. It is common in Devonshire and Somer- setshire, in England, and in Aberdeenshire. In the United States it is associated with the following species in Ver- mont, at Bennington, Brandon, Monkton, Chittenden, and Irasburg ; it occurs also in Maine, at Conway, and Plain- field in Massachusetts ; at Salisbury and Kent, in Conn., on hematite ; on Ked Island, in the Bay of San Francisco ; at Pictou and Walton, Nova Scotia ; near Bathurst, in New Brunswick. MANGANESE. 189 The name pyrolusite is from the Greek pur, fire, and luo, to wash, and alludes to its property of discharging the brown and green tints of glass, for which it is extensively used. Besides the use just alluded to, this ore is extensively em- ployed for bleaching, and for affording the gas oxygen to the chemist. Hausmannite. A manganese oxide, 2 Mn O + Mn 2 , which contains 721 per cent, of manganese, when pure. Brownish black and sub- metallic, occurring massive and in square octahedrons. H. =5-5*5. G.=4'7. From Thuringia and Alsatia. Hetcerolite is a zinc-hausman- nite, from Sterling Hill, N. J. Braunite. An oxide of manganese, containing 69 per cent, of man- ganese when pure. Color and streak dark brownish-black, and lustre submetallic. Occurs in square octahedrons and massive. H. =6-65. G. =4 '8. From Piedmont and Thuringia. Manganite. A hydrous sesquioxide of manganese. Occurs massive and in rhombic prisms. Color steel-black to iron-black. H.=4-4'5. G. :=4 - 3-4 - 4. From the Hartz, Bohemia, Saxony, and Aberdeenshire. It is found at several points in New Brunswick and Nova Scotia. Psilomelane. Massive and botryoidal. Color black or greenish-black. Streak reddish or brownish-black, shining. H. =5-6. G.= 4-4-4. Composition. Essentially manganese dioxide with a little water, and also some baryta or potassa. The compound is somewhat varying in its constitution. Before the blowpipe like pyrolusifce, except that it affords water. Obs. This is an abundant ore, and is associated usually with the pyrolusite. It occurs at the different localities mentioned under pyrolusite, and the two are often in alter- nating layers ; it has been considered an impure variety of the pyrolusite. The name is from the Greek psilos, smooth or naked, and melas, black. Pyrochroite. Hydrous manganese protoxide, of white color. From Sweden. MnO 2 H,. Pdugite. The manganese nodules found in many regions over the bottom of the ocean. Affords, according to an analysis, about 40 per cent, of MnOo, 27 ffe0 3 , l:j of water lost at a red heat, along with 14 per cent, of silica and 4 of alumina ; 24'5 per cent, of water were lost below 100 C. Probably a mixture. Ghalcophanite. A hydrous oxide of manganese and zinc, in rhombo- hedral crystals and stalactites ; from Sterling Hill, N. J. 190 DESCRIPTIONS OF MINERALS. Wad. Bog Manganese. Massive, reniform or earthy ; also in coatings and dendri- tic delineations. Color and streak black or brownish black. Lustre dull, earthy. H. = l-6. G. 3-4. Soils the fingers. Composition. Consists of manganese dioxide, in varying proportions, from 30 to 70 per cent., mechanically mixed with more or less of iron sesquioxide; 10 to 25 per cent, of water, and often several per cent, of oxide of cobalt or cop- per. It is formed in low places from the decomposition of minerals containing manganese. Gives off much water when heated, and affords a violet glass with borax. Obs. Wad is abundant in Columbia and Dutchess coun- ties, N. Y., at Austerlitz, Canaan Centre, and elsewhere; also at Blue Hill Bay, Dover, and other places in Maine ; at Nelson, Gilmanton, and Grafton, N. H.; and in many other parts of the country. It may be employed like the preceding in bleaching, but is too impure to afford good oxygen. It may also be used for umber paint. Lampadite, or Cupreous Manganese. A wad containing 4 to 18 per cent, of copper oxide. Triphylite. Trimetric. In rhombic crystals, massive. Color green- ish gray to bluish gray, but often brownish hlack externally from the oxidation of the manganese present. Streak grayish white. Lustre subresinous. H. =5. G. =3 "54-3 '6. Composition, (JLi 2 f R) 3 8 P 2 , in which R stands for Fe and Mn. A Bodenmais specimen afforded Phosphorus pentoxide 44*19, iron protoxide 38*21, manganese protoxide 5-63, magnesia 2-39, lime 0'76, lithia 7 '69, soda 0'74, pot- ash 0-04, silica -40= 100-05. B.B. fuses very easily, color- ing the flame a beautiful red, in streaks, with a pale bluish- green on the exterior of the flame. Soluble in hydrochloric acid. Obs. Found at Rabenstein in Bavaria ; in Finland ; at Norwich, Mass. ; Grafton, N. H. LitMophilite, A salmon-colored manganese-lithium phospliate, al. lied in composition to triphylite, but containing very little iroa From Redding (near Branchville Depot), Conn. MANGANESE. J^l Triplite. Trimetric. Usually massive, with cleavage in three di- rections. Color blackish brown. Streak yellowish gray. Lustre resinous ; nearly or quite opaque. H.=5-5-5 G = 3-4-38. Composition. (Mn,Fe) 3 8 P 2 + RF 2 , affording about 30 per cent, of manganese protoxide, 8 of fluorine. Fuses easily to a black magnetic globule. B.B. imparts a violet color to the hot borax bead. Dissolves in hydrochloric acid. Obs. From Limoges in France. Rather abundant at Washington, Conn., and sparingly found at Sterling, Mass. Heterosite, Alluaudite, Pseudotriplite, are regarded as results of alteration, either of triphyline or of triplite. Triploidite. A manganese-iron phosphate like triplite, but having the fluorine replaced by the elements of water. From Redding, Conn. Dickinsonite. An oil-green to olive-green manganese-iron-calcium phosphate. From Redding, Conn. Reddingite. A rose-pink hydrous manganese-iron phosphate. Mn, O e P 2 + 3 aq, isomorphous with scorodite and strengite. Redding, Ct. Fairfieldite, hydrous manganese-calcium phosphate. Ibid. Hureaulite. Rose-colored to brownish-orange hydrous manganese- iron phosphate. From Hureaux, France. Rhodochrosite. Manganese Carbonate. Rhombohedral. E A 12= 166 51'; like calcite in hav- ing three easy cleavages, and in lustre. Color rose-red. H. =3-5-4-5. G. = 3'4-3-7. Composition. Mn 3 C = Carbonic acid 386, manganese protoxide 61 '4=100. Part of the manganese often replaced by calcium, magnesium or iron. Obs. From Saxony, Transylvania, the Hartz, Ireland ; Mine Hill, New Jersey ; Redding, Conn. ; Austin, Nevada ; Placentia Bay, Newfoundland. Rhodonite. A manganese silicate. See p. 247 General Remarks. Manganese is never used in the arts in the pure state ; but as an oxide it is largely employed in bleaching. The im- portance of the ore for this purpose depends on the oxygen it con- tains, and the facility with which this gas is given up. As the ores are often impure, it is important to ascertain their value in this re- spect. This is most readily done by heating gently the pulverized ore with hydrochloric acid, and ascertaining the amount of chlorine given off. The chlorine may be made to pass into milk of lime, to form a chloride, and the value of the chloride then tested according to the usual modes. The amount of chlorine derived from a given quantity DESCRIPTIONS OF MINERALS. of muriatic acid depends not only on the amount of oxygen in the ore, but also on the presence or absence of baryta and such other earths as may combine with this acid. The binoxide of manganese, when pure, affords 18 parts by weight of chlorine, to 22 parts of the oxide ; or 23^ cubic inches of gas from 22 grains of the oxide. The best ore should give about three-fourths its weight of chlorine, or about 7,000 cubic inches to the pound avoirdupois. Iron ores containing some manganese are used for making spiegeleisen, a hard highly crystallized pig-iron, containing a large amount of car- bon and some manganese. A manganesian iron carbonate or siderite is thus used, and also the franklinite of New Jersey. Manganese is also employed to give a violet color to glass. The sulphate and the chloride of manganese are used in calico printing. The sulphate gives a chocolate or bronze color. ALUMINUM. The aluminum compounds among minerals include only one oxide a sesquioxide =41 3 hydrated oxides, fluorides, and, among ternaries, sulphates, phosphates, and numerous silicates. There are no sulphides or arsenides, and no car- bonate, with a single imperfectly understood exception. The silicates are described in the following section. Many aluminum compounds may be distinguished by means of a blowpipe experiment, as explained 011 page 87. Corundum. Rhombohedral. R A R or r A r=8G 4'. Cleavage some- times perfect parallel with 0, and sometimes par- allel to the rhombohedral faces. Usual in six- sided prisms, often with uneven surfaces, and sometimes so irregular that the form is scarcely traceable. Occurs also granular. Colors blue, and grayish-blue most common ; also red, yel- low, brown, and nearly black ; often bright. When polished on the surface 0, a star of six rays, corresponding with the six-sided form of the prism, is sometimes seen within the crystal. Transparent to translucent. H. = 9, or next below the diamond. Exceedingly tough when compact. G. =3*9-4*16. Composition. A10 3 = Oxygen 46-8, aluminum 53-2 = 100; pure alumina. B.B. remains unaltered both alone and with soda. The. fine powder moistened with cobalt nitrate and ignited assumes a blue color. COMPOUNDS OF ALUMINUM. 193 VARIETIES. The name sapphire is usually restricted, in common language, to clear crystals of bright colors, used as gems ; while dull, dingy-colored crystals and masses are called corundum, and the granular variety of bluish-gray and blackish colors containing much disseminated magne- tite (whence its dark color) is called emery. Blue is the true sapphire color. When of other bright tints, it receives other names ; as oriental ruby, when red ; oriental topaz, when yellow ; oriental emerald, when green ; oriental amethyst, when violet, and adamantine spar, when hair-brown. Crystals with a radiate chatoyant interior are often very beautiful, and are called asteria, or asteriated mppliire. Diff. Distinguished readily by its hardness, exceeding all species except the diamond, and scratching quartz crystals with great facility. Obs. The sapphire is often found loose in the soil. Meta- morphic rocks, especially gneissoid mica schist, and granu- lar limestone, appear to be its usual matrix. It is met with in several localities in the United States, but seldom suffi- ciently fine for a gem. A blue variety occurs at Newton, K J., in crystals sometimes several inches long ; bluish and pink, at Warwick, N. Y.; white, blue, and reddish crystals at Amity, N. Y. ; grayish, in large crystals, in Delaware and Chester counties, Pennsylvania ; pale blue crystals have been found in bowlders at West Farms and Litchfield, Conn. It occurs also in large quantities in North Carolina, where crystals are numerous though rarely fit for jewelry, and where one has been obtained weighing 312 pounds, and having a reddish color outside and bluish-gray within ; also in Cherokee County, Georgia ; in Los Angeles County, Cali- fornia. Emery is mined at Chester, in Mass. The principal foreign localities are as follows : blue, from Ceylon ; the finest red from the Capelan Mountains in the kingdom of Ava, and smaller crystals from Saxony, Bohemia and Auvergne ; corundum, from the Carnatic, on the Mala- bar coast, and elsewhere in. the East Indies ; adamantine spar, from the Malabar coast ; emery, in large bowlders from near Smyrna, and also at Naxos and several of the Grecian islands. The name sapphire is from the Greek word sapplieiros, the name of a blue gem. It is doubted whether it included the sapphire of the present day. 194 DESCRIPTIONS OF MINERALS. Next to the diamond, the sapphire in some of its varieties is the most costly of gems. The red sapphire is much more highly esteemed than those of other colors. A crystal of one, two or three carats is valued at the price of a diamond of the same size. They seldom exceed half an inch in their dimensions. Two splendid red crystals, as long as the little finger and about an inch in diameter, are said to be in the possession of the king of Arracan. The largest oriental ruby known was brought from China to Prince Gargarin, gov- ernor of Siberia ; it afterward came into the possession of Prince Menzikoff, and constitutes now a jewel in the im- perial crown of Russia. Blue sapphires occur of much larger size. According to Milan, Sir Abram Hume possessed a crystal which was three inches long. One of 9-51 carats is stated to have been found in Ava. Corundum and emery are crushed to a powder of differ- ent degrees of fineness, and make the abrading and polishing jpiaterial called in the shops emery. The iron oxide of true emery diminishes its hardness, and consequently its abrasive power ; pulverized corundum is more valuable and efficient in abrasion. Diaspore. Hydrated aluminum of the formula Al O 4 H 2 = Water 14 '9, alumina 85 '1=100. Usually found assotiated with corundum. Crys- tals usually thin and flattened. Color whitish, grayish, pinkish, etc. Very brittle. Translucent. H. 6 '5-7. G. 3 '5. From the Urals ; Schemnitz ; Chester, Mass. ; Chester County, Pa. ; North Carolina. < Gibbsite (Hydrargillite). Hydrated alumina ; Al 6 H= water 34 '5, alumina 65*5=100. Occurs in hexagonal crystals ; more commonly in stalactitic aiad mammillary forms, with smooth surface, looking like chalcedony. Color white, grayish and greenish -white ; translucent, sometimes transparent when in crystals. H. =2'5-3'5; G.=2'3-2*4. Near Slatoust in the Ural ; in Asia Minor ; on corundum at Unionville, Pa. ; at Richmond, Mass, in stalactitic forms ; in Orange County, N. Y. Hydrotalcite ( Volknerite, Houghite). A soft pearly mineral, contain- ing alumina, magnesia, and water. Accompanies spinel, and some- times a result of the alteration of spinel crystals. Occurs near Sla- toust ; at Snarum, Norway ; near Oxbow in Rossie, St. Lawrence County, N. Y. (the variety Houghite}. Spinel. Isometric. In octahedrons, more or less modified. Fig- ure 4 represents a - twin crystal. Occurs only in crystals ; cleavage octahedral, but difficult. Color red, passing into blue, green, yellow, brown, and .COMPOUNDS OF ALUMINUM. 195 black. The red shades often transparent and bright ; the dark shades usually opaque. Lustre vitreous. II. =8. G.=3-5-4'l. 2. 4. Composition. MgAl 4 =Mg -f- A10 3 = Alumina 72, mag- nesia 28 = 100. The aluminum is sometimes replaced in part by iron, and the magnesium often in part by iron, cal- cium, manganese and zinc. Infusible ; insoluble in acids. VARIETIES. The following varieties of this species have received distinct names : the scarlet or bright red crys- tals, spinel ruby ; the rose-red, balas-ruby ; the orange-red, rubicelle; the violet, almandine-ruby ; the green, cliloro- spinel ; while the black varieties are called pleonaste. Pleo- naste crystals contain sometimes 8 to 20 percent, of oxide of iron. Picotite is a variety containing 7 per cent, of chromium oxide. Diff. The form of the crystals and their hardness dis- tinguish the species. Garnet is fusible. Magnetite is at- tracted by the magnet. Zircon has a higher specific gravity and is not so hard. The red crystals often resemble the true ruby (red corundum), but the latter are never in octa- hedrons. Obs. Occurs in granular limestone ; also in gneiss and volcanic rocks. At numerous places in the adjoining coun- ties of Sussex in New Jersey, and Orange county, of various 19C DESCRIPTIONS OF MINERALS. colors from red to brown and black ; especially at Frank- lin, Newton and Sparta, in the former, and in Warwick, Amity and Edenville, in the latter. The crystals are octa- hedrons, and often grouped or disseminated singly in gran- ular limestone. One crystal, found at Amity by Dr. Heron, weighs 49 pounds. The limestone quarries of Bolton, Box- borough, Chelmsford and Littleton, Mass., afford a few crystals. Crystals of spinel are occasionally soft, having under- gone a change of composition approaching steatite in all characters except form. They are true pseudomorplis. They are met with in Sussex and Orange counties. Other spinel pseudomorplis consist of hydrotalcite (see preceding page). Uses. The fine colored spinels are much used as gems. The red is the' common ruby of jewelry, the oriental rubies being sapphire. Gahnite is a spinel in which zinc takes the place of part or all of the magnesium; when all, it is called Automolite. Color dark green or green- ish black. H. =7-5-8. G. 4-4-6. When fused with sufficient soda, B.B. on coal a white coat of zinc oxide is deposited, which is yellow when hot. B.B. infusible. At Franklin, N. J., and at the Canton mine in Georgia. Occurs in granite at Haddam with beryl, chryso- beryl, garnet, etc. In Sweden, near Fahlun, in talcose slate. Dysluite. A variety of gahnite containing oxide of manganese. Color yellowish or grayish-brown. H.r=7'5-8. G.=4'55. Composi- tion, Alumina 30'5, zinc oxide 16'8, iron sesquioxide 41 '9, manganese protoxide 7 '6, silica 3, water 0'4. From Sterling, N. J., with frank- linite and troostite. Kreittonite is a zinc-iron gahnite. Hercinite is a spinel affording on analysis alumina and iron protoxide, with only 2 '9 per cent, of magnesia. Chrysoberyl. Trimetric. /A 7=129 38'. Also in compound crystals, as in fig. 2. Crystals sometimes thick ; often tabular. Color bright green, from a light shade to emerald-green ; rarely rasptierry or columbine-red by transmitted light. Streak uncolored. Lustre vitreous. Transparent to trans- lucent, H. = 8'5. G. =3-5-3 -8. Composition. Be Al 4 = Alumina 80 -2, glucina 19;8 = 100. A little iron is sometimes present. B.B. infusible and un- altered. Alexandrite is an emerald-green variety from the Urals, colored by chrome, bearing the same relation to ordinary chrysoberyl as emerald to beryl. Fig. 7 is of this variety. COMPOUNDS OF ALUMINUM. 197 Diff. Near beryl, but distinct in not being regularly hex- agonal in crystallization. Obs. Chrysoberyl occurs in the United States in granite at Haddam, Conn., and Greenfield, near Saratoga, N. Y., associated with beryl, garnet, etc. ; in Norway, Maine. 1. The name chrysoberyl is from the Greek chrysos, golden, and beryllos, beryl. The crystals are seldom sufficiently pellucid and clear from flaws to be valued in jewelry ; but when of fine qual- ity, it forms a beautiful gem, and is often opalescent. Fluorides of Aluminum. Cryolite. In snow-white masses, having rectangular cleavages, and remarkable for melting easily in the flame of a candle, to which its name (from the Greek kruos, ice) alludes. H.=2-o. G.=2'95. It is a sodium-aluminum fluoride. Prom Greenland. Chiolite and Chodnefflte are near cryolite in composition and charac- ters. Arksutite, Gearksutite, Pachnolite, Thomsenolite are related fluor- ine compounds which occur associated with the Greenland cryolite. From Siberia. Fluellite. From Cornwall, in minute white rhombic octahedrons. Contains fluorine and aluminum. Alunogen. Hydrous Aluminum Sulphate. In silky efflorescences, and crusts of a white color, having a taste like common alum. H. 1-5-2. G. =1-6-1 '8. Composition. Al 0, 2 S 3 4- ISaq = Sulphur trioxide 36-0, alumina 15-4, water 48-0 = 100. Obs. A common efflorescence in solfataras of volcanic regions, and also often occurring in shales of coal regions and other rocks containing pyrite ; the oxidation of the pyrite an iron sulphide affords sulphuric acid, which acid combines with* the alumina of the shale. 198 DESCRIPTIONS OF MINERALS?. . Alums Frequently the sulphuric acid resulting from the oxidation of a sulphide, or in some other way, combines also with the iron, magnesia or potash or soda of the shale or other rock, as well as the alumina, and so makes other kinds of aluminum sulphate. Combining thus with potash it produces common alum called Kali- nite or potash alum, whose formula is K 2 A1 3 2 < S 4 + 18 aq ; with am- monia, it forms an ammonia-alum, named Tschermigite ; with iron, iron alum, called Halotrichite ; with soda, a soda-alum, Mendozite ; with magnesia a magnesia-alum, Pickeringite ; with manganese, a manganese-alum, Apjohnile and Bosjemanite. The formulas of these alums are alike in atomic proportions, excepting in the amount of water, which varies from 18 aq to 24 aq. Shale containing alunogen or any of the alums is often called alum shale. Such rocks, whether shales or of other kinds, are often quar- ried and lixiviated for the alum they contain or will afford. The rock is first slowly heated after piling it in heaps, in order to decompose the remaining pyrites and transfer the sulphuric acid of any iron sul- phate to the alumina and thus produce the largest amount possible of aluminum sulphate. It is next lixiviated in stone cisterns. The lye containing this sulphate is afterwards concentrated by evaporation, and then the requisite proportion of potassium in the form of the sul- phate or chloride is added to the hot solution. On cooling, the alum crystallizes out, and is afterwards washed and re-crystallized. The mother liquor left after the precipitation is revaporated to obtain the remaining alum held in solution. This process is carried on exten- sively in Germany, France, at Whitby in Yorkshire, Hurlett and Campsie, near Glasgow, in Scotland. Cape Sable in Maryland affords large quantities of alum annually. The slates of coal beds are often used to advantage in this manufacture, owing to the decomposing pyrites present. At Whitby, 130 tons of calcined schist give one ton of alum. In France, ammoniacal salts are used instead of potash, and an ammonia alum is formed. Alum is also manufactured from cryolite (see p. 197), which is ob- tained from Greenland. Alunite. Alum Stone. Rhombohedral, with perfect basal cleavage*. Also mas- sive. Color white, grayish, or reddish. Lustre of crystals vitreous, or a little pearly on the basal plane. Transparent to translucent. H. =4. G. = 2-5S-2'75. Composition. K 2 Al 22 S 4 -fG aq= Sulphuric trioxide 38*5, alumina 371, potash 11'4, water 13-0^100. B.B. decrepi- tates and is infusible ; gives reaction for sulphur. Diff. Distinguished by its infusibility, in connection with its complete solubility in sulphuric acid without forming a jelly- Obs. Found in rocks of volcanic origin at Tolfa, near Rome ; and also at Beregh and elsewhere in Hungary. When it is calcined the sulphates become soluble, and the COMPOUNDS OF ALUMINUM. 199 alum is dissolved out. On evaporation the alum crystallizes from the fluid in cubic crystals. This is called Roman alum, and is highly valued by dyers, because, although the crystals are colored red by iron oxide, no iron is chemically com- bined with the salt as is usual in common alum. Aluminite (Webstcrite). Another hydrous aluminum sulphate, in compact reniform masses, and tasteless. From New Haven, in Sussex ; Epernay, in France ; and Halle, in Prussia. Lcewiyite is a potassium-aluminum sulphate, containing half the water of potash alum. Ambly gonite. Lithium- Aluminum Phosphate. Triclinic, with cleavages unequal in two directions, mak- ing an angle with one another of 104. Lustre vitreous to pearly and greasy. Color pale mountain-green, or sea- green to white. Translucent to subtransparent. H. = 6. G.= 3-3-11. Composition. A lithium-aluminum phosphate, Al O g P 2 + 1 (Li, Na) F. B.B. fuses very easily with intumescence, coloring the flame yellowish red to rich carmine-red, owing to the lithia present, and traces of green owing to the phos- phoric acid. Gives the reaction also for fluorine. Obs. Occurs in Saxony and Norway. HebroniU is a closely related mineral from Hebron and Mount Mica in Maine, and from Redding in Connecticut. Herderite is supposed to be an anhydrous calcium-aluminum phos- phate with fluorine. Durangite. An anhydrous arsenate of an orange-red color, contain- ing aluminum, sodium, iron, and some manganese, with over 7 per cent, of fluorine. From Durango, Mexico, where it occurs with cas- siterite or tin ore. Lazulite. Monoclinic. In crystals and also massive, of an azure-blue color. H.=5-6. G. = 3'057. Composition. RA1 9 P 2 4- aq= Phosphorus pentoxide 46' 8, alumina 34'0, magnesia 13-2, water 6 '0=100. B.B. in the closed tube whitens and yields water ; with cobalt solution the color is restored; in the forceps whitens, swells, cracks, and falls to pieces without fusion, coloring the flame bluish- green. Obs. From Salzburg, Styria; \Vermland, Sweden; Crowder Mount, Lincoln County, JN T . C. ; and on Graves Mountain, Lincoln County, Georgia. 200 DESCRIPTIONS OF MINERALS. Variscite (Peganite, Callainite) is another hydrous aluminum phos- phate ; it is of a light green color, of various shades, to deep emerald- green. From Montgomery County, Arkansas, and from Colorado ; also from Messbach, in Saxon Voigtland. Fischerite, is a related mineral. Turquois. In opaque reniform masses without cleavage; of a bluish- green color, and somewhat waxy lustre. II. 6. G. 2-6 2Q O. Composition. Phosphorus pentoxide 32 *G, alumina 46*9, water 20*5 = 100. 13. B. infusible, but becomes brown and colors the flame green ; soluble in hydrochloric acid ; moist- ened with the acid it gives a momentary bluish green color to the flame, owing to the copper that it contains. Diff. Distinguished from bluish-green feldspar, which it resembles, by its infusibility and the reactions for phos- phorus. Obs. Turquois is brought from a mountainous district in Persia, not far from Nichabour ; and, according to Agaphi, occurs in veins that traverse the mountain in every direc- tion. The Callais of Pliny was probably turquois. Pliny, in his description of it, mentions the fable that it was found in Asia, projecting from the surface of inaccessible rocks, whence it was obtained by means of slings. Turquois receives a fine polish and is highly esteemed as a gem. In Persia it is much admired, and the Persian king is said to retain for himself all the large and more finely tinted specimens. The occidental or lone turquois, is fossil teeth or bones, colored with a little phosphate of iron. Green malachite is sometimes substituted for turquois, but it is of little hardness and has a different tint of color. The stone is so well imitated by art as scarcely to be detected except by chemical tests. The imitation is much softer than true turquois. Childrenite. A hydrous phosphate containing aluminum, iron, with little manganese. Found in trimetric crystals in Devonshire and Cornwall ; also at Hebron in Maine. Eosphorite. Has the crystalline form and nearly the angles of chil- drenite, and contains the same constituents, but differs in being essentially a hydrous phosphate of manganese with little iron. From Bedding, Connecticut. Henwoodite is a hydrous aluminum phosphate from Cornwall, con- taining also copper. COMPOUNDS OF CERIUM, YTTRIUM, LANTHANUM. 201 Wavellite. Trimetric. Usually in small hemispheres a third or half an inch across, attached to the surface of rocks, and having a finely radiated structure within ; when broken off they leave a stel- late circle on the rock. Some- times in rhombic crystals. Color white, green, or yellowish and brownish, with a somewhat pearly or resinous lustre. Sometimes gray or black. Translucent. H. =3*5-4. G. = 2*3. . Composition. Al 3 Oi 9 P 4 + 12aq = Phosphorus pentoxide 35-16, alumina 38-10, water 26 74 = 100. 1 to 2 per cent, of fluorine is often present, replacing the oxygen. B.B. whitens and swells, but does not fuse. Colors the flame green, especially if previously moistened with sulphuric acid. Moistened with cobalt nitrate, assumes a blue color after ignition ; gives much water in the closed glass tube. Diff. Distinguished from the zeolites, some of which it resembles, by giving the reaction of phosphorus, and also by dissolving in acids without gelatinizing. Cacoxene, to which it is allied, becomes dark reddish-brown before the blowpipe, and does not give the blue with cobalt nitrate. Obs. Occurs at the slate quarries of York County, Pa., and also at Washington Mine, Davidson County, N. C. ; at Magnet Cove, Ark. It was first discovered by Dr. Wavel, in clay slate in Devonshire. Occurs also in Bohemia and Bavaria. Zepliaromchite is near wavellite. Mellite or Hon^y stone. In square octahedrons, looking like a honey, yellow resin ; may be cut with a knife. It is an aluminum mellate. Found in Tkuringia, Bohemia, Moravia, etc. Dawsonite. Hydrous aluminum-calcium carbonate, from a felsyte dike near Montreal. CERIUM, YTTRIUM, ERBIUM, LANTHANUM, DIDYMIUM. Known in nature in the condition of fluorides, tantalates, columbates, phosphates, or carbonates, and also as constitu- ents in several silicates. Yttrocerite. Massive, of a violet-blue color, somewhat resembling a 202 DESCRIPTIONS OP MINERALS. purple fluor- spar ; sometimes reddish-brown. Opaque. Lustre glistening. II. = 4-5. G. = 3'4-3'5. (Composition. Fluorine 25'1, lime 47*6, cerium protox- ide 18*2, and yttria 9*1. Infusible alone before the blow- pipe. Obs. From Finbo and Broddbo, near Fahlun, in Sweden, with albite and topaz in quartz. Also from Mt. Mica, Maine ; Massachusetts, probably in Worcester County; and from Amity, Orange County, N.Y. Fluocerite and Fluocerine are other fluorides containing cerium, from Sweden. Samarskite. Trimetric. /A 7=122 46'. Usually massive, without cleavage, with a velvet-black color and shining submetallic lustre. Streak dark-reddish brown. Opaque. H.= 5*5-6. G. = 5-C-5-8. Composition. Analyses of the American afford Columbia and tantalic pentoxide, with sesquioxides of yttrium (12-15 per cent.), cerium, iron, and oxide of uranium. In the closed tube decrepitates and glows. B.B. fuses on the edges to a black glass. With salt of phosphorus in both flames, an emerald-green bead. Obs. Occurs at Miask, in the Ural ; also in masses, sometimes weighing many pounds, at the Mica mines of Western North Carolina, along with columbite. Noldite is near samarskite, but contains 4 "62 of water. Fergusonite. A hydrous columbate of yttrium, erbium, cerium. Color brownish black ; lustre dull, but brilliantly vitreous on a sur- face of fracture. B.B. infusible, but loses its color. From Sweden, Cape Farewell, Greenland, and Rockport, Mass. Kochelite is near fergusonite. Yttro-tantalite. A tantalate and columbate of yttrium, erbium, and iron. The different varieties are the black, the yellow, and brown or dark-colored. They are infusible. From Ytterby, Sweden, and at Broddbo and Finbo, near Fahlun. Euxenite. A columbate and tantalate of yttrium, uranium, erbium, and cerium. Massive. Color brownish black. Streak reddish brown, B.B. infusible. From Norway; also from N. Carolina. Sipylite. A columbate and tantalate of erbium and yttrium, re- sembling fergusonite in aspect. From Amherst County, Va. Pyrochlore, Microlite, Disanalyte, under CALCIUM, p. 214. jEschynite. In crystals, black to brownish yellow ; lustre resinous to submetallic ; streak gray to yellowish brown or black. H. =5-6. G. =4'9-5 1. A columbate and titanate of cerium, thorium, and lan- thanum. From Miask, in the Urals, in feldspar with mica and zircon. Polymignite and Polycrase. Related to seschynite, COMPOUNDS OF CERIUM, YTTRIUM, LANTHANUM. 203 Rogersite. A hydrous columbate of yttria, in whitish crusts, on samarskite. From N. Carolina. Monazite. Monoclinic. In modified oblique rhombic prisms ; I/\I = 93 10'. Perfect and brilliant basal cleavage. Observed only in small imbedded crystals. Color brown, brownish red ; subtransparent to nearly opaque. Lustre vitreous inclining to resinous. Brittle. H. = 5. G. =4-8-51. Composition. A phosphate containing cerium, lantha- num, yttrium, didymium and thorium, with also a little tin, mano-anese, and lime. B.B. it colors the flame green when moistened with sulphuric acid and heated. Difficultly soluble in acids. Diff. The brilliant easy transverse cleavage distinguishes monazite from sphene. Obs. Occurs near Slatoust, Eussia. In the United States it is found in small brown crystals, disseminated through a mica slate at Norwich, Conn. ; also at Chester, Conn., and Yorktown, Westchester County, N. Y. Cryptolite. A cerium phosphate in minute prisms (apparently six. sided), found with the apatite of Arendal, Norway. Color pale wine- yellow. G.=4'6. Churchite. A phosphate of cerium, didymium and calcium ; from Cornwall. Xenotime, An yttrium phosphate having a yellowish-brown color, pale brown streak, opaque, and resinous in lustre. Crystals square prisms, with perfect lateral cleavage. H. =4-5. G. =4'G. Infusible alone before the blowpipe ; insoluble in acids. From Lindesnaes, Norway ; Ytterby, Sweden ; gold washings of Clarkesville, Ga., and McDowell County, N. C. Parisite. Is a carbonate containing cerium, lanthanum, and didy rnium, with fluorine. From New Granada. Lantlianite. Occurs in thin minute tables or scales of whitish or yellowish color, and is a hydrous lanthanum carbonate. From Bast- nas, Sweden, and Saucon Valley in Lehigh County, Pa. Tengerite. An yttrium carbonate. Found in thin coatings at Yt- terby, Sweden. Rliabdophane, A didymium and erbium phosphate ; from Corn- wall, with sphalerite (blende), which it resembles. Rutherfordite. A blackish-brown vitreo-resinous mineral. From the gold mines of Rutherford County, N. C. Allanite, Gadolinite, Keilhauite, and Tscheffkinite, are silicates con- taining either cerium or yttrium. 204 DESCRIPTIONS OF MINERALS. MAGNESIUM. Magnesium occurs, in nature, as an oxide or hydrated oxide, and in the condition of sulphate, borate, nitrate, phosphate, carbonate and silicate. The sulphates and nitrate of magnesia are soluble in water, and are distinguished by their bitter taste ; the other native magnesian salts are insoluble. The presence of magnesia, when no metallic oxides are present, is indi- cated by a blowpipe experiment, explained on page 87. Periclasite. Periclase. Magnesium Oxide. Isometric. In small grayish to dark-green imbedded crystals, with cubic cleavage. H. nearly G. G. 3 - 674. Composition. Mg (or the same as for magnesia alba of the shops), with a little iron. B.B. infusible. Soluble in acids without effervescence. From Mount Somma, Vesuvius, Italy. Brucite. Magnesium Hydrate. Ehombohedral. In foliated hexagonal prisms and plates; structure thin foliated, and thin laminae easily separated and translucent ; flexible but not elastic. Also fibrous. Lustre pearly. Color white, often grayish or greenish. H.=2-5. G.=2'35. Composition. Mg0 2 H 2 =: Magnesia 69-0, water 31-0=100. B.B. infusible, but becomes opaque and alkaline. Soluble in hydrochloric acid without effervescence. Diff. It resembles talc and gypsum, but is soluble in acids ; it differs from heulanditc and stilbite also by its in- fusibility. Obs. Occurs in serpentine at Hoboken, N. J. ; in Rich- mond County, N. Y. ; in Dutchess County, 1ST. Y. , at Brewster's ; at Texas, in Pennsylvania ; also at Swinaness, in Unst, one of the Shetland Isles. The fibrous variety has been called nemalite; it resembles amianthus ; it occurs at Hoboken. Hydromagnesite. A pearly crystalline, or earthy, white, hydrous carbonate of magnesia, from Hoboken, N. J., Texas, Pa., and elsewhere. Spinel contains oxygen and magnesium along with aluminum. See page 195. Magnesium is also present in some magnetite, a variety of which is called magnoferrite. COMPOUNDS OF MAGNESIUM. 203 Chlwmagnesite. A magnesium chloride from Vesuvius. Carnallite. A hydrous magnesium-potassium chloride. Tachydrile. A hydrous magnesium-calcium chloride. Epsomite. Epsom Salt. Magnesium Sulphate. Trimetric. /A 7= 90 34'. Cleavage perfect parallel with the shorter diagonal. Usually in fibrous crusts, or botry- oidal masses, of a white color. Lustre vitreous to earthy. Very soluble, and taste bitter and saline. Composition. Mg 4 S + 7aq = Sulphur trioxide 32*5, mag- nesia 16'3, water 51*2 = 100. Liquefies in its water of crys- tallization when heated. Gives much water which has an acid reaction, in the closed glass tube. B.B. on charcoal fuses, but finally gives an infusible mass that turns pink when moistened with cobalt nitrate and ignited. Diff. The fine spicula-like crystalline grains of Epsom salt, as it appears in the shops, distinguish it from Glauber salt, which occurs usually in thick crystals. Obs. The floors of the limestone caves of the West often contain Epsom salt in minute cr} r stals mingled with the earth. In the Mammoth Cave, Ky., it adheres to the roof in loose masses like snowballs. It occurs as an efflores- cence in the galleries of mines and elsewhere. The fine efflorescences suggested the old name hair-salt. At Epsom, in Surrey, England, it occurs dissolved in min- eral springs, and from this place the salt derived the name it bears. It occurs at Sedlitz, Aragon, and other places in Europe ; also in the Cordilleras of Chili ; and in a grotto in Southern Africa, where it forms a layer an inch and a half thick. Its medical uses are well known. It is obtained for the arts from the bittern of sea-salt works, and quite largely from magnesian calcium carbonate, by decomposing it with sulphuric acid. The sulphuric acid takes the lime and magnesia, expelling the carbonic acid ; and the sulphate of magnesium remaining in solution is poured off from the cal- cium sulphate, which is insoluble. It is then crystallized by evaporation. Polylialite. A brick-red saline mineral, with a weak bitter taste, occurring in masses which have a somewhat fihrous appearance. A hydrous calcium- magnesium sulphate. Kieserite. A hydrous magnesium sulphate ; from Stassfurt. Picromeride. A hydrous potassium - magnesium sulphate ; from Stassfurt. 206 DESCRIPTIONS OF MINERALS. Bladite. A hydrous sodium -magnesium sulphate ; from the salt mines of Ischl, and near Mendoza. Jjoewcite. A hydrous sodium magesium sulphate ; from Ischl. Con' tains more sulphur trioxide than Bleed ite. Isometric. 1. traces. Boracite. Magnesium Borate. Cleavage octahedral ; but only Usual in cubes with only the alternate angles replaced ; or having all replaced, but four of them different from the other four. The crystals are translucent and "seldom more than a quarter of n inch through. Also massive. Color white or grayish ; sometimes yellowish or greenish. Lustre vitreous. H. 7 when in crystals, but softer when massive. G. =2-97. Becomes electric when heated, the opposite angles of the cube be- coming of opposite poles. Composition. Mg 3 15 B 8 + JMg C1 2 = Boron trioxide 62-0, magnesia 31'0, chlorine 7*0=100. B.B. fuses easily with in- tumescence coloring the flame green. The fused globule becomes crystalline on cooling. Dissolves in hydrochloric acid, and moistened with cobalt nitrate turns pink on igni- ,tion. Diff. Distinguished readily by its form, high hardness, And pyro electric properties. Obs. Boracite is found only with gypsum and common salt. It occurs near Luneberg in Lower Saxony, and near Kiel in the adjoining duchy of Holstein, also at Stassfurth, Prussia. Rhodizite. Resembles horacite in its crystals, hut tinges the blow- pipe flame deep red. It is supposed to be a lime-boracite. Occurs with the red tourmaline of Siberia. Ludwigite. A magnesium-iron borate ; fibrous and dark green to black. Szuibelyite. A hydrous magnesium borate, from Southeastern Hungary Warwickite. In rhombic prisms of 93 to 94, hair-brown to black with sometimes a copper-red tinge. A magnesium titanium borate ; from granular limestone of Edenville, N. Y. Sussexite. A hydrous magnesium-manganese borate. Fibrous and pearly. G=3 42. from Mine Hill. Franklin Furnace, Sussex Co., N. J. Nttromagnesite. Occurs in white deliquescent efflorescences, having a bitter taste, associated with calcium nitrate, in limestone caverns. It is used, like its associate, in the manufacture of saltpetre. Wugnerite. A magnesium fluo-phosphate, occurring in yellowish or COMPOUNDS OF CALCIUM. 20? frayish oblique rhombic prisms. Insoluble. H. =5-5 '5. G.^3'1 rom Salzburg, Austria. Kjeralfine is near wagnerite. Hcernisite and ficessleritc are hydrous calcium arsenates. Luneburgite. A magnesium boro-phosphate, from Liineburg. Magnesite. Magnesium Carbonate. Rhombohcdral. R : 72=107 29'. Cleavage rhomboliedral, perfect. Often massive, either granular, or compact and porcelain-like, in tuberose forms ; also fibrous. Color white, yellowish or grayish-white, or brown. Lus- tre vitreous ; fibrous varieties often silky. Transparent to opaque. H.- 3 4'5. G. = 3. Composition. Mg0 5 C = Carbon dioxide 52*4, magnesia 47-6^100. Infusible before the blowpipe. After ignition has an alkaline reaction. Nearly insoluble in cold dilute hydrochloric acid, but dissolves with effervescence in hot. Diff. Kesembles some varieties of calcite and dolomite ; but 'from a concentrated solution no calcium sulphate is precipitated on adding sulphuric acid. The fibrous variety is distinguished from other fibrous minerals by its efferves- c.ence in hot acid, which shows it to be a carbonate. Obs. Magnesite *is usually associated with magnesian rocks, especially serpentine. At Hoboken, N. J., it occurs in this rock in fibrous seams ; similarly at Lynnfield, Mass.; and in Canada, at Bolton, imperfectly fibrous, traversing white limestone. When abundant it is a convenient material for the manu- facture of magnesium sulphate or Epsom salt, to make which, requires simply treatment with sulphuric acid. Ilydromagncsite. A hydrous magnesium carbonate. Occurs with serpentine, at Hoboken, but more abundantly in Lancaster Co. , Penn. Dolomite. A magnesium and calcium carbonate. See page 219. CALCIUM. Calcium exists in nature in the state of fluorite, and this is its only binary compound. It occurs in ternaries in the state of sulphate, borate, columbate, phosphate, arsenate, carbonate, titanate and silicate. The carbonate (calcite and limestone) is one of the three most abundant of minerals. The fluoride and sulphate, and some silicates, are also of very common occurrence. 208 DESCRIPTIONS OP MINERALS. With the exception of the calcium nitrate, none of the native salts of lime are soluble in water except in small proportions. They give no odor, and no metallic reaction before the blowpipe ; but they tinge the flame red, and many of them give up a part of their acid constituent, and become caustic and react alkaline. The specific gravity is below 3 '2, and hardness not above 5. Fluorite. Fluor Spar. Calcium Fluoride. Isometric. Cleavage octahedral, perfect. Commonly in crystals ; rarely fibrous ; often compact, coarse or fine gran- ular. Figures 1 to 4 repffesent common forms. 3. Colors usually bright ; white, or some shade of light green, purple, or clear yellow are most common ; rarely rose-red and sky-blue ; colors of massive varieties often banded. Transparent, translucent or subtranslucent. H = 4. G. =3-3 '26. Brittle. Composition. CaF 2 =Fluorine 48*7, calcium 51 '3 100. Phosphoresces when gently heated in the dark, affording light of different colors ; in some varieties emerald-green ; in others, purple, blue, rose-red, pink, or orange. B.B. decrepitates, and ultimately fuses to an enamel, which pos- sesses an alkaline reaction ; pulverized and moistened with sulphuric acid, hydrofluoric acid gas is given off which cor- rodes glass. The name Clilorophane has been given to the variety that affords a bright green phophorescence. Diff. In its bright colors, fluorite resembles some of the gems, but its softness and its easy octahedral cleavage when crystallized at once distinguish it. Its strong phosphores- cence is a striking characteristic; and also its affording COMPOUNDS OF CALCIUM. 209 easily, with sulphuric acid and heat, a gas that corrodes glass. Obs. Fluorite occurs in gneiss, mica schist, clay slate, limestone, and sparingly in beds of coal either in veins or occupying cavities, or as imbedded masses. It is the gangue in some lead mines. Cubic crystals of a greenish color, over a foot each way, have been obtained at Muscolonge Lake, St. Lawrence County, N. Y. ; near Shawneetown on the Ohio, a beautiful purple fluor in grouped cubes of large size is obtained from limestone and the soil of the region ; at Westmoreland, N". H., at the Notch in the White Mountains, Blue Hill Bay, Maine, Putney, Vt., and Lockport, N. Y., are other locali- ties. The chlorophane variety is found with topaz at Trum- bull, Conn. In Derbyshire, England, fluor spar is abundant, and hence it has received the name of Derbyshire spar. It is a com- mon mineral in the mining districts of Saxony. Calcium fluoride also exists in the enamel of teeth, in bones and some other parts of animals ; also in certain parts of many plants ; and by vegetable or animal decomposition it is afforded to the soil, to rocks, and also to coal beds in. which it has been detected. Massive fluor receives a high polish, and is worked into vases, candlesticks and various ornaments, in Derbyshire, England. Some of the varieties from this locality, consist- ing of rich purple shades banded with yellowish white, are very beautiful. The mineral is difficult to work because brittle. Fluor spar is also used for obtaining hydrofluoric acid, which is employed in etching. To etch glass, a pic- ture, or whateverdesign it is desired to etch, is traced in the thin coating of wax with which the glass is first covered; a very small quantity of the liquid hydrofluoric acid is then washed over it ; on removing the wax, in a few minutes, the picture is found to be engraved on the glass. The same process is used for etching seals, and any siliceous stone will be attacked with equal facility. This application of fluor spar depends upon the strong affinity between fluorine and silicon. Fluor spar is also used as a flux to aid in re- ducing copper and other ores, and hence the 10 DESCRIPTIONS OF MINERALS. Gypsum. Hydrous Calcium Sulphate. Monoclinic. /A 7=143 42' ; 22A2i + lH 42'. Figure 2 represents a common twin (or arrow-head) crystal. Cleav- age parallel to i-l very easy, affording thin pearly laminae ; parallel to 0, im- perfect, giving a vitreous surface ; par- allel to /, fibrous. Occurs also in lam- inated masses, often of large size ; in fibrous masses, with a satin lustre ; in stellated or radiating forms consisting of narrow laminae ; also granular and com- pact. When pure and crystallized it is as clear and pellucid as glass, and has a pearly lustre. Other varieties are gray, yel- low, reddish, brownish, and even black, and opaque. 1-1.= 1 '5-2,orso soft as to be scratched by the finger-nail. G. = 2'33, The plates bend in one direction and are brittle in another. Composition. Ca 4 S + 2 aq Sulphur trioxide 4(ro, lime 32-6, water 20 '9 = 100. B.B. becomes instantly white and opaque and exfoliates, and then fuses to a globule, which when placed upon moistened turmeric paper shows an alka- line reaction. In a closed tube much water is given off. Dissolves quietly in hydrochloric acid, and the solution gives a heavy precipitate with barium chloride. The principal varieties are as follows : Selenite, including the transparent crystallized gypsum, so called in allusion to its color and lustre from selene, the Greek word for moon. Radiated and Plumose gypsum, having a radiated struc- ture. Fibrous gypsum or satin S2)ar, white and delicately fibrous. Snowy g ijp sum and Alabaster, including the white or light- colored compact gypsum having a very fine grain. Diff. The foliated gypsum resembles some varieties of heulandite, stilbite, talc, and mica ; and the fibrous looks like fibrous carbonate of lime, asbestus and some of the fibrous zeolites ; but gypsum in all its varieties is readily distinguished by its softness ; its becoming an opaque white powder immediately and without fusion before the blow- pipe, and by not effervescing or gelatinizing with acids. Obs. Gypsum forms extensive beds in certain limestones and clay beds, and also occurs in volcanic regions. New York, near Lockport, affords beautiful selenite and snowy - COMPOUNDS OP CALCIUM. 211 gypsum in limestone. At Camillas and Manlius, N. Y., and in Davidson County, Term., are other localities. Fine crys- tals of the form represented in figure 5 come from Poland and Canfield, Ohio, and large groups of crystals from St. Mary's in Maryland. Troy, N. Y., also affords crystals in clay. In Mammoth Cave, Kentucky, alabaster occurs in imitation of flowers, leaves, shrubbery, and vines. Alabas- ter is obtained at Castelino in Italy, 35 miles from Leghorn. Massive gypsum occurs abundantly in New York, from Syracuse westward to the western extremity of Genesee County, accompanying the rocks which afford the brine springs ; also in New Brunswick, especially at Hillsboro', where part is excellent alabaster; in Hants, Colchester, and other districts in Nova Scotia; also in Ohio, Illinois, Vir- ginia, Tennessee, Arkansas, and Nova Scotia; and in con- nection with the Triassic beds of the Rocky Mountain region; also abundant in Nevada and California. It is abundant also in Europe. Gypsum, when calcined, loses its water, becomes white, is easily ground to a powder. This powder, when mixed with a little water, takes up water again and becomes hard and compact. This gypsum is plaster of Paris, and is used for taking casts, making models, and forgiving a hard finish to walls. Alabaster is cut into vases and various ornaments, statues, etc. It owes its beauty for this purpose to its snowy whiteness, translucency, and fine texture. Moreover, owing to its softness, it can be cut or carved with common cutting instruments. Gypsum is ground up and used for improving soils. Anhydrite. Anhydrous Calcium Sulphate. Trimetric. In rectangular and rhombic prisms, cleaving easily in three directions, and readily breaking into square blocks. /A/=10030"*; 1UH=85 and 95. Occurs also fibrous and lamellar, often contorted ; also coarse and fine granular, and compact. Color white, or tinged with gray, red, or blue. Lustre more or less pearly. Trans- parent to subtranslucent. II. 3-3*5. G. = 2'iff. Its fibrous forms and its blowpipe reactions are distinctive. Obs. Occurs mostly in cavities or seams in trap or basic eruptive rocks, and occasionally in other rocks. Found at Ratho Quarry, near Edinburgh, Scotland ; at Kilsyth ; Isle of Skye ; in the Tyrol ; in fine specimens at Bergen Hill, N. J. ; a compact variety at Isle Royale, Lake Supe- rior. Okenite and Gyrolite are related hydrous calcium silicates. Okenite is from the Faroe Islands, Iceland, and Greenland, and gyrolite from the Isle of Skye, and from Nova Scotia 25 miles southwest of Cape Blomidon. Liaumontite. Monoclinic, with the angles nearly of pyroxene ; /A /= 86 16'. Cleavage parallel to the clinodiagonal section and to / perfect. Also massive, with a radiating or divergent structure. Color white, passing into yellow or gray, sometimes red. Lustre vitreous, inclining to pearly on the cleavage face. Transparent to translucent. H. = 3'5-4. G.=2'25-2'36. Becomes opaque on exposure through loss of water, and readily crumbles. Composition. CaAl 0, 5 Si 4 + 4 aq= Silica 50'0, alumina 21-8, lime 11-9, water 16-3 = 100. B.B. swells up and fuses easily to a white enamel. Decomposed by hydrochloric acid, and the solution gelatinizes on evaporation. Diff. The alteration this species undergoes on exposure to the air at once distinguishes it. This result may be prevented with cabinet specimens, by dipping them into a solution of gum arabic. 294 DESCRIPTIONS OF MINERALS. Otis. Found in the veins and cavities of trap rocks and also in gneiss, porphyry. Occurs at the Faroe Islands ; Kil- patrick Hills, near Glasgow ; Disco, Greenland ; St. Groth- ard, Switzerland ; Peter's Point, Nova Scotia ; Phippsburg, Me.; Charlestown syenite quarries, Mass. ; Bergen Hill, N. J. ; the Copper region, Lake Superior, and Isle Royale. Leonhardite. Probably Laumontite which has lost part of its water by alteration. It resembles that species in crystallization and in most of \ts characters, but differs in being less efflorescent on exposure to a dry atmosphere. Analyses of specimens from Copper Falls, Lake Superior, have obtained, Silica 55'50, alumina 2.1 '19, lime 10'5G, water 11*93 = 99-68. The Copper Falls variety alters little on exposure. Reported also from trachyte at Schemnitz, in Hungary, and from Pfitsch in the Tyrol Apophyfflte. Dimetric. In square octahedrons, prisms, and tables. Cleavage parallel with the base highly perfect. Massive 1. 3. and foliated. Color white or grayish ; sometimes with a shade of green, yellow, or red. Lustre of O pearly : of the other faces vitreous. Transparent to opaque. H.=4*5 5. G. =2 -3-2-4. Composition. A silicate of calcium and hydrogen com- bined, with potassium fluoride and water, of the formula (JH 2 Ca) 3 Si + KF+iaq = Silica 52'97, lime 24-^2, potash 5-20, water 15 '90, fluorine 2-10=100-89. B.B. exfo- liates, colors the flame violet (owing to the potash), and fuses very easily to a white enamel. In the closed tube yields water which has an acid reaction. Decomposed by hydrochloric acid with the separation of slimy silica. HYDROUS SILICATES GENERAL SECTION. 295 Diff. The pearly basal cleavage and the forms of its glassy crystals at once distinguish it from the preceding species. The prisms are sometimes almost cubes, with the angles cut oif by the planes of the pyramid ; but the difference in the lustre of the prismatic and basal faces shows that it is dimetric. The name alludes to its exfoliation before the blowpipe. Obs. Found in amygdaloidal trap and basalt. Occurs in fine crystallizations at Peter's Point and Par- tridge Island, Nova Scotia, at Bergen Hill, N. J., the Cliff Mine, Lake Superior region. Catapleiite. A hydrous zirconium and sodium silicate, from Nor- way. Dioptase and Chrysocolla. Hydrous copper silicates. See p. 141. Picrosmine, Pyrallolite, Picropliyll, Traversellite, Pitkaraiulite, Stra- konitzite, Monradite, are names of varieties of pyroxene in different stages of alteration. Xylotine is probably altered asbestus. Frehnite. Trimetric. /A 7=99 56'. Cleavage basal. Sometimes in six-sided prisms, rounded so as to be barrel-shaped, and composed of a series of united plates ; also in thin rhom- bic or hexagonal plates. Usually reniform and botryoidal, with a crystalline surface ; texture compact. Color light green to colorless. Lustre vitreous, except the face 0, which is somewhat pearly. Subtransparent to translucent. H. = 6-6-5. G. =2-8-2 '96. Composition. H 2 Ca 2 A10i 2 Si 3 = Silica 43-6, alumina 24*9, lime 27'1, water 4-4=100. B.B. fuses very easily to an en- amel-like glass. Decomposed by hydrochloric acid, leaving a residue of silica in light flakes, but the solution does not gelatinize. Yields a little water when heated in a closed tube. Diff. Distinguished from beryl, green quartz, and chal- cedony by fusing before the blowpipe, and from the zeolites by its superior hardness. Obs. Found in the cavities of trap, gneiss, and granite. Occurs in the trap rocks of the Connecticut Valley, and at Paterson and Bergen Hill, N. J. ; in gneiss at Bellows Falls, Vt. ; in syenyte at Charlestown, Mass. ; and very abundant, forming large veins, in the Copper region of Lake Superior, three miles south of Cat Harbor, and elsewhere. The Fassa Valley in the Tyrol, St. Christophe in Dau- 296 DESCRIPTIONS OP MINERALS. phiny, and the Salisbury Crag, near Edinburgh, are some of the foreign localities. Prehnite receives a handsome polish and is sometimes used for inlaid work. In China it is polished for orna- ments, and large slabs have been cut from masses brought from there. Clilorastrolitc and Zonochlorite, from the Lake Superior region, are impure prehnite. Chalcomorphite. A hydrous calcium silicate, from calcite in cavities of lava, containing but 25 "4 per cent, of silica. Gismondite (Zeagonite). A hydrous lime-aluminum silicate, occur- ring in trimetric crystals resembling square octahedrons ; found in lava at Capo di Bove, near Rome. Edingtonite. A hydrous barium-aluminum silicate. Occurring in crystals and massive. From the Kilpatrick Hills, with harmotome. Carpholite. A manganese- aluminum silicate, occurring in silky, yellow, radiated tufts. From the tin mines of Schlackenwald. PyrosmaMte. A manganese-iron silicate and chloride, from Sweden. Goldmine. A hydrous zinc unisilicate. See p. 157. Villarsite. Probably altered chrysolite. Cerite, Tritomite, Erdmannite, are cerium and lanthanum silicates. Thorite (Orangite) and JSucrasite, are thorium silicates ; the latter hydrous. Allophane. In amorphous incrustations, with a smooth small-mam- millary surface, and often hyalite-like, and sometimes pul- verulent. Color pale bluish-white to greenish-white, and deep green ; also brown, yellow, colorless. Translucent. H.=3. G.= 1-85-1-89. Composition. Mostly Al 5 Si + 6 (or 5) aq. Silica 23-75, alumina 40*6^, water 35-63 = 100. In the closed tube yields much water. B.B. infusible, but crumbles. A blue color with cobalt solution, and a jelly with hydrochloric acid. Occurs in Saxony ; at the Chessy Copper Mine near Lyons ; at a copper mine in Bohemia ; with limonite in Moravia ; in Old Chalk Pits near Woolwich, England ; with gibbsite in limonite beds in Richmond, Mass. ; at the cop- per mine of Bristol, Conn.; at Morgantown, Pa.; copper mines of Polk County, Tenn. Collyrite. A hydrous aluminum silicate containing only 14 to 15 per cent, of silica, and 35 to 40 of water ; and Schrotterite is another with 11 to 12 per cent, of silica. The latter has been reported as occurring, as a gum-like incrustation, at the falls of Little River, on Sand Moun- tain, Cherokee Counfy, Alabama. Scarbroite is a related mineral of doubtful nature. HYDROUS SILICATES ZEOLITE SECTION. 297 II. ZEOLITE SECTION. The species of the Zeolite Section have beer/ described as having some relation to the feldspars in constitution. In the feldspars, as explained on page 273, the following ratios, for the protoxides, alumina, and silica which analyses af- ford, occur: 1:3:4,1:3:6,1:3:8,1:3:9,1:3:10, 1:3:12. So, among the zeolites, if the water be left out of considera- tion, these are the ratios: 1:3:4 (in Thomsonite), 1:3:6 (Natrolite, Scolecite, etc.), 1:3:8 (Analcite, Chabazite, etc.), 1:3:10 (Harmotome), 1:3: 12 (Stilbite, Heulandite, etc.). This fact, added to the absence or nearly total ab- sence of magnesium and iron, and presence instead of Na 2 , K 2 , Ca, Ba, make out a distinct relation to the feldspars, whatever may be the part which the water sustains in the compounds. Besides barium, strontium is sometimes pres- ent, an element not yet known to characterize a species of feldspar. These minerals were called zeolites because they generally fuse easily with intumescence before the blowpipe, the term being derived from the Greek zeo, to boil. Among those described beyond, Heulandite and Stilbite, have a strong pearly cleavage, and the latter is often in pearly radiations ; Natrolite, Scolecite, are fibrous and radiated, or in very slender prisms ; Thomsonite occurs either radiated, or com- pact, or in short crystals ; while Harmotome, Analcite, and Chabazite, and the related Gmelinite, occur only in short or stout glassy crystals, those of chabazite looking some- times like cubes. The zeolites are sometimes called trap minerals, because they are often found in the cavities or fissures of amygda- loidal trap as well as related basic eruptive rocks. Yet they occur also occasionally in fissures or cavities in gneiss, granite, and other metamorphic rocks. They are not the original minerals of any of these rocks ; but the results of alteration of portions of them near the little cavities or fis- 298 DESCRIPTIONS OP MINERALS. sures in which the minerals occur ; and part were made while the rock was still hot, and as cooling went forward. Besides true zeolites, such cavities often contain also Laumontite (p. 293), noted for its tendency to crumble on exposure ; Pectolite and Okenite (p. 293), which are fibrous like Natrolite and Scolecite ; Apophyllite (p. 294), having one pearly cleavage like heulandite and stilbite ; Prehnite (p. 295), usually apple-green ; Datolite (p. 289), in stoutish glassy complex crystals, or in smooth botryoidal forms ; Aragonite (p. 218), sometimes radiated fibrous, and Calcite (p. 215) with its three directions of like easy cleav- age, both effervescing with hydrochloric acid ; Siderite (p. 185), in spheroidal or other forms ; Chlorite (p. 316), of dark olive-green color ; and Quartz, either in crystals, or as chalcedony, agate, or carnelian, and in either case easily distinguished by the hardness, absence of cleavage, and infusibility. Of all these species Calcite and Quartz are the most common. Of rarer occurrence than the above, there are Orthoclase, Asphaltic coal, Copper, etc. All the zeolites yield water in the closed tube, and many of them gelatinize with hydrochloric acid. Thomsonite. Trimetric. In right rectangular prisms. Usually in masses having a radiated structure within, and consisting of long fibres, or acicular crystals ; also amorphous. Color snow-white ; impure varieties brown. Lustre vi- treous, inclining to pearly. Transparent to translucent. H.=5-5. Brittle. G. =2-3-2-4. Composition. (Ca,Na 2 )Al 8 Si, +.2 Jaq= Silica 38-09, al- umina 31-62, lime 12-60, soda 4-62, water 13 "40 =100 '20. B. B. fuses very easily to a white enamel. Decomposed by hydrochloric acid: the solution gelatinizes when evaporated. ' Diff. Distinguished from natrolite by its fusion to an opaque and not to a glassy globule. Obs. Occurs in amygdaloid, near Kilpatrick, Scotland ; in lavas at Vesuvius, Comptonite; in clinkstone in Bohemia; the Tyrol, etc. ; at Peter's Point, Nova Scotia, in trap ; a massive variety, called Ozarkite, at Magnet Cove, Ark. HYDROUS SILICATES ZEOLITE SECTION. The species was named after Dr. Thomas Thomson, of Glasgow. Natrolite. Trimetric. In slender prisms, terminated by a short pyra mid; /A/=91; 1 Ai over a?=U3 20'. Also in globular, stellated, and divergent groups, consisting of delicate acicular fibres, the fibres often terminating in acicular prismatic crystals. Color white, or inclining to yellow, gray, or red. Lustre vitreous. Transparent to translucent. H. = 5-5'5. G. = 2 -1 7-2 -25. Brittle. Composition. NagAl 0, Si 3 + 2 aq = Silica 47'29, alumina 26*06, soda 16*30, water 9 '45 = 100. B.B. fuses easily and quietly to a clear glass ; a fine splinter melts in a candle flame. Decomposed by hy- drochloric acid, and the solution gelatinizes on evaporation. Diff. Distinguished from scolecite by its quiet fusion. Obs. Found in amygdaloidal trap, basalt and volcanic rocks; sometimes in seams in granitic rocks. The name natrolite is from natron, soda. Occurs in Bohemia; Auvergne; Fassathal, Tyrol; at Glen Farg in Fifeshire ; in Dumbartonshire ; Nova Scotia ; Ber- gen Hill, N. J. Scolecite. Resembles natrolite, and differs in containing lime in place of soda ; also in having its slender rhombic glassy prisms longitudi- nally twinned, as is shown by the meeting of two ranges of striae at an angle along or near the central line of opposite prismatic planes. The lustre is vitreous or a little pearly. B.B. it curls up like a worm (whence the name from the Greek skolex, a worm) and then melts. From Staffa, Iceland, Finland, Hindostan. Mesolite. Another related species. Analcite. Dimetric or Trimetric. Occurs usually in trapezohedron (fig. 1, also fig. 2). The appearance sometimes seen in polarized light is shown in figure 7, page 69 On account of this peculiar behavior and indications of a compound structure ob- tained in a microscopic study 1. 300 DESCRIPTIONS OF MINERALS. of thin slices, it has been suspected to be dimetric like leucite, or else t rime trie like phillipsite, although the forms of the crystals are apparently isometric. Often colorless and transparent, also milk-white, grayish and reddish- white, and sometimes opaque. Lustre vitreous. H. =5-5 '5. G.=2 25. Composition. Na 2 Al Oi 2 Si 4 4- 2aq = Silica 54*47, alumina 23-29, soda 14-07, water 8-17 = 100. B.B. fuses easily to a colorless glass. Decomposed by hydrochloric acid ; and the silica separates in gelatinous lumps. Diff. Characterized by its crystallization, without cleav- age. Distinguished from quartz and leucite by giving water in a closed glass tube ; from calcite by its fusibility, and by not effervescing with acids ; from chabazite and its varieties by fusing without intumescence to a glassy globule, and by the crystalline form. Obs. Found in cavities and seams in amygdaloid'al trap, basalt and other eruptive rocks, and sometimes in granite, syenyte and gneiss. Occurs in fine crystallizations in Nova Scotia ; also at Bergen Hill, N. J. ; Ferry, Me. ; and in the trap of the Cop- per region, Lake Superior. The Faroe Islands, Iceland ; Glen Farg, near Edinburgh ; Kilmalcolm, the Campsie Hills, and Antrim ; the Vicentine ; the Hartz at Andreas- berg ; Sicily, and Vesuvius, are some of the foreign localities. The name analcite is from the Greek, analkis, weak, al- luding to its weak electric power when heated or rubbed. EudnopMte. Near analcite. From Norway. Faujasite. In isometric octahedrons. From the Kaiserstuhl, Baden. Chabazite. Rhombohedral. Often in rhombohedrons, much resem- bling cubes. R : 72=94 46'. Cleavage parallel to R. Also in complex modifications of this form. Never massive or fibrous. Color white, also yellowish, and flesh-red or red. Lustre vitreous. Transparent to translucent. H. 4-5. G. =2-08-3-19. The red chabazite of Nova Scotia has been called Acadi- alite. Composition. CuAl 0, 2 Si 4 -f 6aq, with a little Na 2 or K 2 in place of part of the Ca. The Nova Scotia acadialite afforded HYDROUS SILICATES ZEOLITE SECTION. 301 Silica 52*20, alumina 18*27, lime 6 '58, soda and potash 2*12, water 20-52. B. B. intumesces and fuses to a nearly opaque bead. Decomposed by hydrochloric acid, with the separa- tion of slimy silica. In the closed tube gives water. Phac- olite is a variety in complex glassy crystals. Diff. The nearly cubical form often presented by the crystals of chabazite is a striking character. It is distin- guished from analcite as stated under that species ; from calcite by its hardness and action with acids ; from fluorite by its form and cleavage, and its showing no phosphores- cence. Obs. Found in trap and occasionally in gneiss, syenyte, and other rocks. Chabazite is met with in the trap of Con- necticut Valley, but in poor specimens ; also at Hadlyme and Stonington, Conn.; Charlestown, Mass.; Bergen Hill, N. J. ; Piermont, N. Y.; Jones's Falls, near Baltimore (Haydenite). Nova Scotia affords common chabazite, and also the acadialite in abundance. The Faroe Islands, Ice- land, and Giant's Causeway, are some of the foreign locali- ties ; also the County of Antrim, Ireland. Herschdite. Near chabazite, if not identical with it. From Sicily. Omelinite. Closely resembles some chabazite, but its crystals are usually hexagonal rather than rhombohedral in appearance. Formula (Na2,Ca)Al 2 O, 2 Si 4 . A Bergen Hill specimen afforded Silica 48 67, alu- mina 18'72, lime 2 -60, soda 9 '14, water 21 -35 =100 '48. Gelatinizes with hydrochloric acid, but in other respects resembles chabazite. Occurs at Andreasberg ; in Antrim, Ireland ; in Skye ; at Bergen Hill, N. J. ; in Nova Scotia at Cape Blomidon. Named after the chemist, Gmelin. Levynite (Let>yne\ Rhombohedral, and somewhat resembling gme- nite in its crystals ; excluding the water, having the quantivalent itio of labradorite, 1:3:6. Colorless, white, grayish, reddish. From eland, Greenland, Antrim, Londonderry, Hartfield Moss near Glas- >w. Named after the crystallographer, Levy. Harmotome. Monoclinic. Unknown except in compound crystals; and commonly in forms similar to the annexed figure ; also in compound rhombic prisms. Color white ; sometimes gray, yellow, red, or brownish. Subtransparent to translucent. Lustre vitreous. H. = 4'5. Cr. = 2-45. Composition. BaAl 14 Si 5 + 5 aq = Silica 46 *5, alumina 1 5 '9, baryta 23 '7, water 13 -9 = 100 ; but a little of the baryta re- placed by potash. B.B. whitens, crumbles, and fuses quietly 302 DESCRIPTIONS OP MINERALS. to a white translucent glass. Gives water in a closed glass tube. Partially decomposed by hydrochloric acid, and if sulphuric acid be added to the solution, a heavy white precipitate of barium sul- phate is formed. Some varieties phos- phoresce when heated. Diff. Its twin crystals, when distinct, cannot be mistaken for any other species except phillipsite. Much more fusible than glassy feldspar or scapolite ; does not gelatinize in acids like thomsonite. Ofa. Occurs in amygdaloidal trap, and in trachyte and phonolyte, also in gneiss, and metalliferous veins. Fine crystallizations are found at Strontian in Scotland, and in Dumbartonshire ; Andreasberg in the Hartz ; Kongs- berg in Norway. Has been found in seams in the gneiss of the upper part of New York Island. The name harmotome is from the Greek Jiarmos, a joint, and temno, to cleave. Phillipsite. Near harmotome in its cruciform crystals and other characters ; but differing in containing lime in place of baryta. It differs also in gelatinizing with acids and in fusing with some intumescence. It also occurs in sheaf -like aggregations and in radiated crystallizations. From the Giant's Causeway, Capo di Bove, Vesuvius, Sicily, Iceland. Epistttbite. A hydrous silicate of alumina and lime. Occurs in thin rhombic prisms, of a white color, with a perfect pearly cleavage like stilbite.' H.=4-4'5. G.=:2'2o. Before the blowpipe froths and forms a vesicular enamel. Does not gelatinize. From Iceland and Hindostan, and sparingly at Bergen Hill, N. J. Bravaisite. Supposed to be a zeolite ; it has potassium, magnesium and iron as the protoxide bases. Stilbite. In pyramidally terminated rectangular prisms usually flattened parallel to the face i~i, which is the direction of cleavage and is very pearly in lustre. 1A1 = 119 16', and 114. Also in sheaf-like ag- gregations, and thin lamellar and columnar ; also in pearly radiated crystallizations. Color white ; sometimes yellow, brown or red. Subtransparent to translucent. H.= 3*5-4. G.= 2 -1-2 -15. HYDROUS SILICATES SEOLITE SECTION. 303 Composition. CaAl 16 Si 6 + 6 aq = Silica 57*4, alumina 16*5, lime 8-9, water 17*2=: 100; but with a little Na 2 or K 2 in place of part of the Ca. B.B. exfoliates, swells up, and curves into fan-like forms, and fuses to a white enamel. Decomposed by hydrochloric acid without gelatinizing. Diff. It cannot be scratched with the thumb-nail, like gypsum. It is distinguished from heulandite by its crys- tals. Obs. Occurs mostly in trap-rocks ; also on gneiss and granite. Found on the Faroe Ids. ; Isle of Skye ; Isle of Ar- ran, and elsewhere, Scotland ; Andreasberg, Hartz ; the Ven- dayah Mts., Hindostan. Found sparingly at the Chester and Charlestown syenite quarries, Mass.; at New Haven, Thatchersville and Hadlyme, Conn., and other points in the Connecticut Valley trap ; at Phillipstown, N. Y.; at Bergen Hill, N. J. ; in trap, in the copper region of Lake Superior ; in beautiful crystallizations at various points in Nova Scotia. The name stilbite is derived from the Greek stilbe lustre. It has also been called desmine, and in Germany heulandite, where heulandite has been called stilbite. Heulandite. Monoclinic. In right rhomboidal prisms like the figure, with perfect pearly cleavage parallel to P and other planes vitreous in lustre. P on M or T=90 ; M on T r=129 40'. Color white ; sometimes reddish, gray, brown. Transparent to subtrnsl cent. Folia brit- tle. H. =3-5-4. G. =2-17- *& Composition. CaA10, 6 Si, + 5 aq= Silica 59*1, alu- mina 16-9, lime 9'22, water 14-8=100. Contains 1 to 2 per cent, of Na f or K 2 in place of part of the Ca. Blowpipe characters like those of stilbite. In- tumesces and fuses, and becomes phosphorescent. Dis- solves in acid without gelatinizing. Diff. The very pearly lustre of the cleavage face is a marked characteristic. 'Distinguished from gypsum by its hardness ; from apophyllite and stilbite by its crystals ; and from the latter species also in not occurring in radiated crystallizations. Obs. Found in amygdaloidal cavities and fissures in trap ; occasionally in gneiss, and in some metalliferoug 304 DESCRIPTIONS OP MINERALS. veins ; in large crystallizations at Berufiord, Iceland ; and Vendayah Mts., Hindostan ; also at Isle Skye ; near Glasgow ; Fassa Valley ; at Bergen Hill, N. J., in trap ; at Hadlyme, Conn., and Chester, Massachusetts, on gneiss ; near Baltimore, on a syenitic schist (Beaumontite) ; at Peter's Point and Cape Blomidon, and other places in Nova Scotia, in trap. The species was named by Brooke after Mr. Heuland, of London. Brewstcrite. Crystals monoclinic with a perfect pearly cleavage like heulandite ; but M : T = 93 40'. H.=4i-5. G.=2 45. The for- mula is analogous to that of heulandite, but baryta and strontia take the place of the lime and soda. Epistilbite. Composition like that of beulandite, but occurs in short and very obtuse rhombic prisms, (/A/=135 10'), at Skye ; the Faroe Ids., in Iceland ; at Margaretville, in Nova Scotia. Mordenite. Fibrous mineral from Morden, Nova Scotia. Pilinitc. In slender needles, from Silesia. ' Foresite. Near stilbite. From Elba. III. MARGAROPHYLLITE SECTION. Talc. Trimetric. In right rhombic or hexagonal prisms. I/\l = 120. Usually in pearly foliated masses, separating easily into thin translucent folia. Sometimes stellate, or diver- gent, consisting of radiating laminae. Often massive, con- sisting of minute pearly scales ; also crystalline granular, or of a fine impalpable texture. Lustre eminently pearly, and feel unctuous. Color some shade of light green or greenish white ; occasionally silvery white; also grayish green and dark olive-green. H. =1- 1*5; easily impressed with the nail. G. =2*5-2-8. Lam- inae flexible, but not elastic. There are the following varieties : Foliated Talc. The pure foliated talc, of a white or greenish-white color. Soapstone or Steatite. Gray or grayish green, and either massive, crystalline granular, or impalpable ; very greasy to the touch. French chalk is a milk-white variety, with a pearly lustre. Potstone or Lapis Ollaris is impure soap- stone of grayish-green and dark-green colors, and slaty structure. HYDROUS SILICATES MARGAROPHYLLITE SECTION. 305 Indurated Talc, is a slaty talc, of compact texture, and above the usual hardness, owing to impurities. Rensselaerite. A compact crypto-crystalline rock, from St. Lawrence and Jefferson counties, N.Y., of white, yellow, or grayish-white colors, and even black. It has sometimes the form and cleavage of pyroxene, and is in part at least a product of the alteration of that mineral. Composition. ^H 2 f Mg 3 Si = Silica 62-8, magnesia 33'5, water 3'7 = 100. It usually contains a little iron replacing magnesium. 13. B. infusible. Moistened with cobalt nitrate assumes a pink tint. Not acted upon by hydrochloric acid. In closed tube gives a little water, but not till highly heated. Diff. The softness, unctuous feel, foliated structure, when crystallized, and pearly lustre of talc are good characteris- tics. It differs from mica also in being inelastic, although flexible ; from chlorite, kaolinite, and serpentine in yielding little water when heated in a glass tube. Only the massive varieties resemble the last-mentioned species, and chlorite has a dark olive-green color. Pyrophyllite, which cannot be distinguished in some of its varieties from talc, becomes dark blue when moistened wifch cobalt nitrate and ignited. Obs. Occurs in Cornwall, near Lizard Point ; at rortsoy in Scotland ; at Croky Head, Ireland ; in the Greiner Mountain, Saltzburg. Handsome foliated talc occurs at Bridgewater, Vt. ; Smithfi Id, R. I. ; Dexter, Me. ; Lock- wood, Newton and Sparta, N. J., and Amity, N. Y. On Staten Island, near the Quarantine, both the common and indurated are obtained ; at Cooptown, Md., green, blue, and rose-colored talc occur. Steatite or soapstone is abun- dant, and is quarried at Grafton, Vt., and an adjacent town ; at Francestown and Orford, N. H. It also occurs at Keene and Richmond, N. H. ; at Marlboro' and New Fane, Vt. ; at Middl field, Mass. ; in Loudon County, Va., and at many other places. Steatite may be sawn into slabs and turned in a lathe. It is used for firestones in furnaces and stoves, and fire-places. It receives a polish after being heated, and has then a deep olive-green color. The finer kinds are made into images in China, and into inkstands and other forms in other coun- tries. Potstone is worked into vessels for culinary pur- poses in Lombardy. The harder kinds are cut into gas jets. Steatite is also used in the manufacture of porcelain ; it 306 DESCRIPTIONS OP MINERALS. makes the biscuit semi-transparent, but brittle and apt to break with slight changes of heat. It forms a polishing material for serpentine, alabaster and glass. " French chalk" is used for removing grease-spots from cloth, as well as for tracing on cloth. When ground up, soapstone is employed for diminishing the friction of machinery. Pyrophyllite. Agalmatolite, in part. Near talc in crystallization, cleavage, its occurrence in fine-grained massive forms, its greasy feel, its white to pale- green colors, varying to yellowish, its feeble degree of hard- ness (1-2). The folia are sometimes radiated. G.=2'75- 2-92. Composition. An aluminous bisilicate, instead of a mag- nesian, for the most part of the formula, Al 9 Si 3 . The Chesterfield, S. C., ; mineral afforded Genth, Silica 64-82, alumina 24*48, iron sesquioxide 0*96, magnesia 0*33, lime 0-55, water 5-25 100-39. B.B. whitens and fuses with dif- ficulty on the edges. Gives a deep blue color with cobalt solution. Yields water in the closed tube. Kadiated varie- ties exfoliate in fan-like forms. Obs. Compact pyrophyllite is the chief constituent of a kind of slate or schist, which is used for slate pencils, and henee is called pencil-stone. Occurs in the Urals ; at \Ves- tana in Sweden; in Elfdalen, with cyanite ; foliated, in North Carolina, in Cottonstone Mountain ; in South Caro- lina, in Chesterfield District, with lazulite and cyanite ; Georgia, in Lincoln County, on Graves Mountain ; in Ar- kansas, near Little Rock ; compact slaty in the Deep River region, N. C., and at Carbonton, Moore County, N. C. Sepiolite. Meerschaum of the Germans. Usually compact, of a fine earthy texture, with a smooth feel, and white or whitish color ; also fibrous, white to bluish- green in color. H.=2-2-5. The earthy variety floats on water. Composition. iH 2 f Mg 3 Si 4- 1 aq = Silica 60-8, magnesia 27*1, water 12-1 = 100. B.B. infusible, or fuses with great difficulty on the thin edges. Much water in a closed tube. A pink color with cobalt solution. Occurs in Asia Minor in masses in stratified earthy de- posits, and is extensively used for pipe bowls ; also found in HYDROUS SILICATES MARGAROPHYLLITE SECTION. 307 Greece, Moravia, Spain, etc. ; also in fibrous seams at a sil- ver mine in Utah. Aphrodite. Similar to the preceding. MgOsSi+fH. From Swe- den. Cimolite, a clay from the Island of Argentiera, Kimole of the Greeks. Smectite, a kind of "Fuller's Earth," a name given to unc- tuous clays used in fulling cloth. MontmoriUonite, Stolpenite, and Steargillite, are related clay-like minerals. Glauconite. Green Earth. In dark olive-green to yellowish-green grains, or granular masses, with dull lustre. H. =2. G.^2^-2-4. Composition. Essentially a silicate of iron and potassium. Formula RR 12 Si 4 , in which R is mainly Fe and K, with sometimes Mg ; and R is Al, but sometimes largely Fe. Analy- ses give mostly 50-58 per cent, silica, 20-24 iron protoxide, 4-12 of potash and 8-12 of water. B.B. fuses easily to a magnetic glass. Yields water in a closed tube. Obs. In a more or less pure state it forms thick beds in the Cretaceous formation, and also in the Lower Tertiary of New Jersey ; also occurs in other older rock formations down to the Lower Silurian. Found also, first by Four- tales, in the pores of corals and cavities of Rhizopod shells over the existing sea-bottom, showing it to be a marine product, and one now in progress of formation. The grains of the Cretaceous, Tertiary, and Lower Silurian beds have been shown by Ehrenberg to be the casts of the interior of shells of Rhizopods. The silica has been supposed to come from the siliceous secretions of a minute sponge growing in the cavities that afterwards became occupied by the glau- conite. Celadonite. A green earth with 53 per cent, of silica, from amygda- loid, near Verona. Probably an impure chlorite. Chloropal. A massive greenish-yellow to pistachio-green compact mineral, somewhat opal-like in appearance, consisting chiefly of silica, iron sesquioxide, and water. Montronite, Pinguite, Unghwarite and Gramenite are varieties of it. Stilpnomelane. Foliated and also fibrous, or as a velvety coating. Black to brownish and yellowish bronze in color and lustre. G.= 3-8-4. Chiefly silica and iron oxides, with 8 to 9 per cent, of water. Chalcodite of the Sterling Iron Mine, Antwerp, Jefferson County, N. Y., is here included. Serpentine. Usually massive and compact in texture, of a dark oil- green, olive-green, or blackish-green color ; also pale yel- 308 DESCRIPTIONS OP MINERALS. lo wish-green, brownish-yellow and brownish-red. Occurs also fibrous and lamellar. The lamellar varieties consist of thin folia, sometimes separable, but brittle ; colors green- ish-white, and light to dark green. Often in crystals pseu- domorphous after chrysolite, chondrodite, and some other minerals. Lustre weak ; resinous, inclining to greasy. Finer varie- ties translucent; also opaque. H. =2'5-4. G. = 2'5-2*6. Feel sometimes a little unctuous. Tough. Fracture con- choidal. Composition. A hydrous silicate of magnesium, like talc, but containing much more water and much less silica. HjMg 3 8 Si 2 + l aq = Silica 43 '48, magnesia 43*48, water 13'04 = 100. B.B. fuses with much difficulty on thin edges. Yields water in the closed tube. Decomposed by hydro- chloric acid, leaving a residue of silica. In some kinds the Mg is replaced partly by Fe. Specimens of a rich oil-green color, and translucent, bi caking with a splintery fracture, are sometimes called precious serpentine, and the opaque kind, common serpen- tine. Fibrous serpentine with a silky lustre is called Chrysotile, and also Amianthus. Unlike asbestus, which it resembles, it affords much water in a closed tube. Metaxite, Picro- lite, and Baltimorite are coarse fibrous kinds. A foliated variety, from Hoboken, N. J., was named Marmolite, be- fore it was known to be serpentine. Antiyorite is a foli- ated variety. Williamsite is similar. Refdanskite contains nickel. A porcelain-like serpentine the Meerschaum of Taberg and Sala has been called Porcello$)hite ; and a resin-like variety, Retinalite and Vorhauserite. Diff. The distinguishing characters are feeble lustre, somewhat resinous, compact structure, little hardness, being so soft as to be easily cut with a knife, and specific gravity not over 2*6. Obs. Serpentine occurs as a rock, and the several varie- ties mentioned either constitute the rock or occur in it. Occasionally it is disseminated through granular limestone, giving the latter a clouded green color : this is the verd an- tique marble, called also Opliiolyte. Serpentine occurs in Cornwall ; near Portsoy in Aber- deenshire, in Corsica, Siberia, Saxony, Norway at Snarum. HYDROUS SILICATES MARGAROPHTLLITE SECTION. 309 In the United States it occurs at Phillipstown, Port Henry, Gouverneur, Warwick, N. Y. ; Newburyport, Westfield, and Bltindford, Mass.; at Kellyvale and New Fane, Vt. ; Deer Isle, Maine ; New Haven, Conn. ; Bare Hills, Md. ; Hoboken, N. J. ; at Brewster's, Putnam County, N. Y., where it occurs pseudomorphous after chondrodite, chlo- rite, enstatite, biotite, etc. ; in Canada at Orford, Ham, Bol- ton, etc. Serpentine forms a handsome marble when polished, es- pecially when mixed with limestone, constituting verd- antique marble. Its colors are often beautifully clouded, and it is much sought for as a material for tables, jambs for fire-places, and ornamental in-door work. Exposed to the weather, it wears uneven, and soon loses its polish. Chromic iron is usually disseminated through it, and in creases the variety of its colors. Near Milford and New Haven, Conn., a handsome verd-antique marble occurs which was formerly worked. A white limestone, dotted and spotted with green serpentine at Port Henry, Essex County, N. Y., is much esteemed for its beauty, and is now extensively worked. The name serpentine alludes to the varied green colors of such rocks. Bowenite from Smithfield, R. I., has the composition of serpentine, but the hardness 5 '5-6, and the aspect of nephrite, with G. 2 '59-2' 8. Bastlte or Schiller Spar, is a foliated pyroxene or bronzite altered nearly to serpentine. AntUlite is similar. Deweylite. Massive. Whitish, yellowish, brownish-yellow, greenish, reddish, in color, with the aspect of gum arabic or a resin. Very brittle. H. =2-3 5. G. = l'9-2-25. In composition near serpentine but containing 20 per cent, of water. From Middlefield, Mass. ; Bare Hills, Maryland (Qymnito); T^xas, Pa., and from the Fleims Val- ley, Tyrol. Cerolite. Related to deweylite ; from Silesia. Limbachito from Lim* bach, and Zoblitzite from Zoblitz, are similar. Hydrophite. Like deweylite, but containing iron in place of part of the magnesium. From Taberg in Smaoland. Jenkinsite is a fibrous variety, occurring on magnetite, at O'Neil's mine in Orange County, N. Y. Genthite or Nickel-gymnite. Similar to deweylite, but containing much nickel and G.= 2 '4, analysis affording Silica 35 '36, nickel pro- toxide 30-64, iron protoxide 0'24, magnesia 14*60, lime 0'26, water 310 DESCRIPTIONS OP MINERALS. 19- 09 =100 -19. From Texas, Pa. ; Webster, N. C. ; Michipicoton Island, Lake Superior ; Malaga, Spain ; Saasthal, Upper valois. Eottisite is similar. Saponite. Soft, clay-like, of the consistence before drying of cheese or butter, but brittle when dry. Color white, yellowish, grayish-green, bluish, reddish. Does not adhere to the tongue. Composition. A hydrous silicate of magnesia containing some alumina. From Lizard's Point, Cornwall, in serpentine. Also from geodes of datolite, Roaring Brook, Conn. ; in trap, north shore of Lake Superior. Eaolinite. Trimetric. /A 7= 120. Occurs massive, clay-like, but consisting usually of thin, microscopic, rhombic or hex- agonal, crystals ; either compact, friable, or mealy. Color wliite, grayish-white, yellowish, sometimes brown- ish, bluish, or reddish. Scales transparent or translucent ; flexible, inelastic, greasy to the touch. H. = 1-2 '5. G.= 2-4-2-6. Composition. H 2 A1 8 Si 2 + l aq= Silica 46 '4, alumina 39*7, water 13'9 = 100. The similarity of the composition to that of serpentine will be seen on comparing the two formulas. B. B. infusible. A blue color with cobalt solution. Yields water in the closed tube. Insoluble in acids. Obs. The soapy feel of kaolinite distinguishes a clay con- sisting of it from other kinds of clay ; and when common clays are " unctuous " it is usually owing to the presence of kaolinite. Kaolinite has been made through the decompo- sition of aluminous minerals, and especially the potash and soda feldspars, orthoclase, albite, and oligoclase. In the case of these feldspars the process (1) removes the alkalies ; (2) leaves the alumina, or a large part of it, and part of the silica ; and (3) adds water. So that, with orthoclase, K 2 Al O 16 Si 6 becomes changed to H 2 A1 8 Si 2 + l aq ; half the water which is added replaces K 2 which is removed. Many gran- ites, gneisses, and other feldspar-bearing rocks undergo rapidly this change, so that extensive beds of kaolinite have been formed and are now making in many regions. The kaolinite is usually washed out by streams or the waves from the decomposed material to make the large pure deposits. HYDROUS SILICATES MARGAROPHYLLITE SECTION. 311 The New Jersey clay-beds of the Cretaceous formation are mainly kaolinite, and have been thus formed. In other cases permeating waters have washed out the oxides of iron present, and have left the white clay in place. A pure kaolinite bed occurs at Brandon, Vermont, along with a limonite bed, where the rock decomposed was probably a feldspathic hydromica slate. Most of the limonite beds of Western New England afford kaolinite ; yet it is generally more or less colored by iron oxide. Common clays consist of finely-powdered feldspar, quartz, and other mineral material, with often more or less kaoli- nite. They burn red in case they contain iron in the state ordinarily present in them of iron carbonate, or hydrous iron oxide (limonite), or in combination with an organic acid, or in some other alterable state of composition, heat driving off the carbonic acid or water, or destroying the or- ganic acid, and so leaving the red oxide of iron (or sesqui- oxide), or favoring its production. But the iron may be so combined as not to give the red color; and this has been found to be true with the clays from which the cream-col- ored Milwaukee (Wisconsin) brick are made, and that of other clay beds in that vicinity. The iron may be there in the state of the silicate, zoisite, or epidote. Pure kaolinite (or kaolin as it is ordinarily called) is used in making the finest porcelain. For this purpose it is mixed with pulverized feldspar and quartz, in the proportion needed to give, on baking, that slight incipient degree of fusion which renders porcelain translucent. The name kaolin is a corruption of the Chinese word Kauling, mean- ing high ridge, the name of a hill near Jauehau-Fu, where the mineral is obtained; and i\\Qpetuntze (peh-tun-tsz) of the Chinese, with which the kaolin is mixed in China for the manufacture of porcelain, is, according to S. W. Williams, a quartzose feldspathic rock* consisting largely of quartz. The word porcelain was first given to China-ware by the Portuguese, from its resemblance to certain sea-shells called Porcellana; they supposed it to be made from shells, fish- glue, and fish-scales (8. W. Williams). The impure kaolin is used for stoneware and fire-bricks. The presence of iron, in any state, makes a clay more or less fusible, and therefore an unfit material for fire-bricks. But a little of it exists in all clays employed for making or- dinary bricks, and hence their red color. 312 DESCRIPTIONS OF MINERALS. Pholerite, Hattoysite, Smectite, Severite, Glagerite, Lenzinite, Bole, Li thomarge, are names of clay-like minerals. Finite. Amorphous, and usually cryptocrystalline ; but often having the form of the crystals of other minerals from the alteration of which it has been made. Colors grayish, green- ish, brownish, and sometimes reddish. Lustre feeble; waxy. Translucent to opaque. Acts like a gum on polarized light, and thus indicates the absence of true crystallization, even when under the forms of crystals. H.=2'5-3. G. 2-6-2'85. Composition. Mostly (H 3 K) 2 A1 2 Q m Sis. The pinite of Saxony afforded Silica 46-83, alumina 27*65, iron sesquioxide 8 -71, magnesia 1-02, lime 0*49, soda 0'40, potash 6 '52, water 3 '83 = 99-42 ; and, in another analysis, potash 10*74. The phy- sical characters ally it to serpentine, and also nearly the atomic ratio, and it may be viewed as a potash-alumina ser- pentine. But at the same time it has very nearly the com- position of a hydrous potash mica, or damourite (see next page). Obs. The varieties are pseudomorphs after different min- erals, and hence comes a part of their variations in compo- sition. They include Pinite, from the Pini Mine, near Schneeberg and elsewhere ; Gieseckite, pseudomorph after nephelite from Greenland, and from Diana, N. Y. ; Dysyn- tribite, from Diana, identical with gieseckite ; Pinitoid, from Saxony ; Wilsonite, from Bathurst, Canada, having the cleavage of scapolite ; Terenite, from Antwerp, N. Y., like Wilsonite ; Agalmatolite, or Pagodite, from China, be- ing one of the materials for carving into images, ornaments, models of pagodas, etc. ; gigantolite and iberite, which have the form of iolite. Polyargite, Eosite, Cataspilite, Biharite are related materials. Palagonite. Yellow to brownish yellow, garnet-red to black in color, and resinous to vitreous in lustre. The material of some tufas, and the result of change through the agency of steam or hot water at the time, probably, of the deposition of the material. From tufas of Iceland, Germany, Italy, Sicily, and named from Palagonia, in Sicily. HYDROMIOA GROUP. The following species are mica-like in cleavage and aspect, but talc-like in wanting elasticity, greasy feel, ajid pearly lustre. They arc sometimes brittle. Common mica, mus- HYDROMICA GROUP. 313 covite, readily becomes hydrated on exposure ; but hydrous micas are not all a result of alteration. The Hydromica slates form extensive rock-formations, equal to those of the ordinary mica schists. They were for the most part called Talcose slates (or Talk-scUiefer in German) from their greasy feel, until the fact was ascertained that they contained no magnesia : a point demonstrated for the Taconic slates of the western border of Massachusetts, by C. Dewey, in 1819, and later, by G. F. Barker, for those of Vermont. Finite is related in composition, but is not micaceous. Margarodite. Like muscovite (page 267), but inelastic. Composition. Specimens from the topaz vein, Trunftmll, Conn., afforded Silica 46'50, alumina 33 '91, iron sesquiox- ide 2-69, magnesia 0-90, soda JJ '70, potash 7'32, water 4-63, fluorine 0-82, chlorine 0-31 = 99-78. Another from Litch- field, Conn., accompanying cyanite, afforded water 5*26 per cent., soda 4-10, potash 6-20, showing a large percentage of soda. It is probable that both of these micas were originally hydrous. Damourite. Mica-like, consisting of an aggregation of fine pearly scales, yellow to white in color. Composition. Near margarodite, being a hydrous potash mica. A specimen from Brittany afforded Silica 45-22, alumina 37 '85, potash 11 '20, water 5-25 = 99-52. The quan- tivalent ratio for the protoxide, sesquioxide, silica, and water is 1: 9: 12:2, instead of that of margarodite, which is 1:6:9:2. A schistose hydromica slate from Lehigh County, Pennsylvania, afforded Dr. Genth, Silica 49 '92, alumina 34-06, iron sesquioxide 0*91, magnesia 1/77, lime 0-11, soda 0-74, potash 6 -94, water 6 -52 = 100-97. Obs. From a locality of cyanite in Brittany, and another in Warmland ; also the constituents of a garnetiferous schist at Salm-Chateau, in Belgium; and in part of extensive schistose formations in Vermont, Western Massachusetts, "Western Connecticut, and also just west of New Haven, Connecticut ; Eastern Pennsylvania, etc. 314 DESCRIPTIONS OF MINERALS. For other analyses of hydromica slates, see Dr. Genth's report on the Mineralogy of Pennsylvania ; also Geological Report of F. Prime, Jr., for 1874, p. 12. Parophitc. The material of a schist or slate Parophite Schist which cuts like massive talc, is of greenish, yellowish, reddish, and grayish colors, and is probably a damourite or hydromica slate, with some free silica (quartz). An analysis afforded Silica 48 '46, alumina 27*55, iron protoxide 5 '08, magnesia 2 '02, lime 2 '05, ^oua 2 '35, potash 516, water 7 14=99 '81. It is from Pownal, Vt., and St. Nicholas, Stanstead, and other neighboring parts of Canada. Sericite. A damourite-like mineral, with the pearly lustre of talc, and the composition of a hydrous mica ; it is the basis of a glossy schist ; near Wiesbaden. The scales are described by Rosenbusch as appearing fibrous when highly magnified. Analysis afforded Silica 49-00, alumina 23'65, iron protoxide 8*07, magnesia 94, lime 0*63, soda 1*75, potash 9 '11, water 3 '47, titanic dioxide 1/39, silicon fluoride 1-60=100-14. Paragonite. A hydrous mica containing soda in place of potash. From Mount Campione, in the region of St. Gothard. Color whitish, grayish, yellowish, greenish. Analysis afforded Silica 46 '81, alu- mina 40 06, magnesia 0'65, lime 1*26, soda 6 '40, potash trace, water 4-82=100. Pregrattite. from the Tyrol, afforded soda 7'06, potash 1-71, water 5 '04 ; it exfoliates like the Vermiculites. Cossaite is here included. Groppite. A rose-red to brownish-red foliated mineral from Gropp- torp, Sweden. EuphyUite. Mica -like, with folia rather brittle, pearly lustre, white or colorless. Contains much sodium. An analysis afforded Silica 41-6, alumina 42*3, lime 1 -5, potash 3 '2, soda 5 '9, water 5 '5 =100. Occurs with corundum at Unionville, Delaware County, Pa. (EUacherite. Mica-like ; strong pearly in lustre, grayish white to white ; elastic. Analysis obtained 7 '61 potash, 1'42 soda, 4*65 baryta, and 4'43 water, besides silica, alumina, etc. Cookeite. In minute mica-like scales, and in slender six-sided prisms. Affords only 2 '57 of potash, with 2 '82 of lithia ; the water 13*41 per cent. Occurs on crystals of red tourmaline at Hebron and Paris, Me., and has proceeded from its alteration. Named after Prof. J. P. Cooke, of Cambridge, Mass. Voigtite is the mica of a granite at Ehrenberg, near Ilmenau, which has the composition of biotite, plus 9 to 10 per cent, of water. Roscoelite. A vanadium-mica, of dark brownish-green color, occur- ring in micaceous scales, and affording over 20 per cent, of vanadium oxides, along with 47*69 of silica, 14'10 of alumina, 7 '59 of potash, 4*96 of water, and a little magnesia and soda. From Granite Creek Gold Mine, El Dorado County, California. Fahlunite In six and twelve-sided prisms, usually foliated, parallel to the base, but owing its prismatic forms to the mineral from which it was derived. Folia soft and brittle, of a HYDROUS SILICATES. 315 grayish-green to dark olive-green color, and pearly lustre. G. =2-7. Composition. A hydrous silicate of aluminum and iron with little or no alkali, and in this last point differing from pinite. An average specimen afforded Silica 44-60, alumina 30-10, iron protoxide 3-86, manganese protoxide 2-24, mag- nesia 6*75, lime T35, potash 1-98, water 9'35 = 100-2-3. B.B. fuses to a white glass. In a closed tube gives water. Insoluble in acids. Diff. It is distinguished from talc by affording much water before the blowpipe, and readily by its association with iolite, and its large hexagonal forms, with brittle folia. Obs. Fahlunite has been derived from the alteration of iolite. The quantivalent ratio of iolite for the protoxides, sesquioxides, and silicon is 1:3:5; and for fahlunite, the same, with 1 for the water, making the whole 1:3:5:1. The hydration appears to go on at the ordinary temperature, and in some localities all the iolite to a considerable depth in the rock is changed to fahlunite. There are different varieties, depending on the amount of water, and the con- ditions under which the change has taken place. The names they have received are Hijdrous Iolite, Chlorophyllite, Esrnarkite, Aspasiolite, Pyrargillite, Triclasite. Fahlunite was so named from its locality, Fahlun, Sweden ; and Chlo- Tophyllite from its greenish color and foliated structure ; the specimens to which it was given occurring at Unity, N. H. Haddam, Ct., is another locality. Gigantolite, Iberite, are also altered iolite, but they contain potash, and belong hence to the Pinite Group. Hisingerite. Massive ; reniform ; of a black to brownish-black color, yellowish-brown streak, greasy lustre inclining to vitreous. H.=3. G.=3'045. Composition. A hydrous iron silicate. Silica 35'9, iron sesquioxide 42'6, water 21-5 = 100. But in some analyses part of the iron is in the protoxide state. B.B. fuses with difficulty to a magnetic slag. Obs. From Sweden, Norway, Finland. Scotiolite and Deyeroite are referred to it. Melanolite, from Milk-Row quarry, near Charlestown, Mass., is related in composition, if the material analyzed was a pure species. 316 DESCRIPTIONS OF MINERALS. Approaches in composition the chlorites, and may belong to that group. Gillingite from Sweden, including Thraulitc from Bavaria, EpicMo- rite, and Lillite, are other hydrous silicates containing iron . Ekmannite, foliated, chlorite-like, occurs in the rifts of magnetite, in Sweden ; it is a hydrous iron silicate, but the iron is mostly in the protoxide state. Neotocite (Stratopeite) and Wittingite are results of the alteration of rhodonite, and contain manganese. Stubelite also contains manganese oxide. Slrigomte from Striegau, Siberia, and Jollyte from Bodenmais in Bavaria, are hydrous silicates of aluminum and iron, with little mag- nesium. CHLORITE GROUP. The chlorite group includes the hydrous Subsilicates of the Margarophyllite Section and also some related species that are Unisilicates. The proportion of silica is small, the percentage afforded by analyses being under 38, and mostly under 30. The minerals when well crystallized are foliated like the micas, and have the plane angle of the base of the crystals 120, but the folia are inelastic and in some species brittle. They also occur in fibrous and in fine granular and compact forms, and the latter are usually most common. Green, varying from light to blackish green, is the prevail- ing color, yet gray, yellowish, reddish, and even white and black also occur ; and the colored transparent or translu- cent are dichroic. The green color is owing to the presence of iron, and fails only in species containing little or none of it. All of the species yield water in a closed tube. The quantivalent (or combining-power) ratio for R + & and Si is, in the Pyrosclerite subdivision 1:1. Chlorite subdivision 1 : i, 1 : f, 1 : . Chloritoid subdivision 1 : to 1 : . The chlorite subdivision includes Penninite, Ripidolite and Prochlorite, together with some related dark -green to blackish-green species. Some species of this subdivision characterize extensive rock formations, making chlorite CHLORITE GROUP. 317 schist or slate ; and they give rise also to chloritic varieties of other rocks. Moreover, chlorite is a result of the altera- tion of pyroxene, hornblende, and some other iron-bearing minerals ; and pyroxcnic igneous rocks, like doleryte, are often strongly chloritic (as revealed by the microscopic examination of thin transparent slices), in consequence of this alteration but alteration that took place before the rock had cooled. Such green chloritic material, where the species is not determinable, has been called Viridite. The cavities in amygdaloid are often lined, and sometimes filled, by a species of chlorite, which was made from certain con- stituents of the amygdaloid in the manner just stated ; and the rocks adjoining trap dikes are at times penetrated by chlorite made in them by means of the heat, and the mois- ture contained in them or ascending with the erupted rock. Pyrosclerite. Trimetric or monoclinic. Mica-like in cleavage ; folia flexible, not elastic, and pearly in lustre. Color apple-green to emerald-green. H.=3. G. =2'74. Composition, (f Mg s JA1), 18 Si 3 + 3 aq = Silica 38 '9, alu- mina 14-8, magnesia 34-6, water 11'7=100. B.B. fuses to a grayish glass ; gelatinizes with hydrochloric acid. Obs. Occurs in serpentine, on Elba. Chonicrite (Metaxoite) is related to the above in composition, but affords 13 to 18 per cent, of linie. Vermiculite. Mica-like in cleavage. Grayish, brownish, and yellowish- brown in color. In aggregated scales. Also in large mi- caceous crystals or plates. Laminae flexible, not elastic. Lustre pearly. Composition. Mg 3 (Fe,Al) 12 Si 3 . When heated it exfo- liates, and when scaly-granular the scales open out into worm-like forms ; and thence the name, from the Latin vermicular, I breed worms ; B.B. fuses finally to a gray mass. From Milbury, Mass. Jefferisite is a similar mineral in composition and exfoliation, occur- ring in broad folia. Composition Mg 3 (Fe 2 ,Al 2 )O 12 Si 3 . From veins in serpentine in Westchester, Pa. Culsageeite from Culsagee, North 318 DESCRIPTIONS OP MINERALS. Carolina ; Hallite from Lerni, Delaware Co., Pa. ; Protovermiculite from Magnet Cove, Ark., are other micaceous hydrous unisilicates similar to vermiculite and jefferisite in exfoliation. Kerrite and Maconite are related to the above. They are from Franklin, Macon Co., North Carolina. Pdhamite is from Pelham, Mass. Penninite. Chlorite in part. Pennine. Khombohedral. Cleavage basal and highly perfect, mica- like. Also massive, consisting of an aggregation of scales, and cryptocrystalline. Color green of various shades ; also yellowish to silver- white, and rose-red to violet. Lustre pearly on cleavage surface. Transparent to translucent. Laminae flexible, not elastic. H. = 2-2-5, 3 on edges. G.= 2 -6-2-85. Composition. A specimen from Zermatt, in the Pennine Alps, aiforded Silica 33-64, alumina 10'64, iron sesquioxide 8-83, magnesia 34-95, water 12-40=100-46. The rose-red, from Texas, Pa., gave Silica 33*20, alumina 11-11, chro- mium oxide 6-85, iron sesquioxide 1*43, magnesia 35 '54, water 12-95, lithia and soda 0-28, potash 0-10 = 101-46. Other Texas specimens afforded 0-90 to 4'78 per cent, of chromium oxide. B.B. exfoliates somewhat and fuses with difficulty. Partially decomposed by hydrochloric acid, and wholly so by sulphuric acid. From Zermatt, Ala in Piedmont, the Tyrol, etc. Kdm- mererite, Rhodochrome, and Rhodophyllite include the red- dish variety from near Miask, Russia ; Texas, Pennsylva- nia ; etc. Pseudomorphs after hornblende, named Loganitt have the composition of this species ; and so has the mas- sive mineral called P seudopliite and Allophite. Ddessite. A fibrous mineral near the above in composition, from amygdaloid at Oberstein. Euralite is an amorphous chlorite near Penninite, from Eura, Fin- land ; from amygdaloid. Diabaniite (Diahantoclironyri] is a chlorite from amygdaloid. A Farmington (Conn.) specimen afforded Hawes, Silica 33 "68, alumina 10'84, iron sesquioxide 2'86, iron protoxide 24'33, MnO and CaO I'll, magnesia 16'52, soda 0'33, water 10'02=99-69. Chlorophwite is a doubtful species of chlorite, from amygdaloid. Ripidolite. Chlorite, in part. Monoclinic. Similar in cleavage and mica-like character to penninite, and also in its colors, lustre, hardness and specific gravity. CHLORITE GROUP. 319 Composition. A specimen from Chester Co. , Pennsylvania, afforded Silica 31*34, alumina 17-47, chromium sesquioxide 1 -69, iron sesquioxide 3*85, magnesia 33-44, water 12-60= 100 "39. B.B. and with acids nearly like penninite. A va- riety from Willimantic, Ct., exfoliates like vermiculite and jefferisite. Kotscliubeite is a red variety from the Urals. Clinochlore and Grastite are here included. Occurs at Achmatovsk and elsewhere in the Urals ; at Ala, Piedmont ; at Zermatt ; at Westchester, Union ville and Texas, Pa. ; at Brewster's, N. Y. Prochlorite. Chlorite in part. Hexagonal. Similar in cleavage and mica-like characters the preceding. Color green to blackish-green ; some- imes red across the axis by transmitted light. Laminae >t elastic. Composition. A specimen from St. Gothard afforded Sili- 25*36, alumina 18*56, iron protoxide 28 '79, magnesia 17*09, water 8-96 = 98-70 ; and a North Carolina specimen, Silica 24-90, alumina 21*77, iron sesquioxide 4*60, iron protoxide 24*21, manganese protoxide 1*15, magnesia 12*78, water 10-59=100. B.B. same as for preceding. Lophoite, Ogcoite, Helminthe belong here. Occur at St. Gothard, at Greiner in the Tyrol, at Traversella in Pied- mont, and many other places in Europe. Also at Steele's Mine, N. C. Leuchtenbergite is a proclilorite with the base almost solely magne- sium. Aphrosiderite, Metachlorite are near the above in composition. Venerite is a pale-green earthy chlorite, from a magnetite mine in Berks County, Pa. Corundophilite is a chlorite near prochlorite in composition. Occurs with corundum at Asheville, N. C. Orochauite is from Grochau in Silesia. Cromtedtite. Hexagonal, with perfect basal cleavage. Black. G.= 3'35. Consists mainly of silica, iron oxides, and water, with a little manganese oxide. From Bohemia and Cornwall. Thuringite. Another hydrous iron silicate, having G.=3'15-3-20, from Thuringia, and also Hot Springs, Arkansas, and near Harper's Ferry, on the Potomac. Patter sonite, from Union ville, Pa., is near it. Margarita. Emerylite. Diphanite. Clingmanite. Corundellite. Trimetric. Foliated, mica-like. Laminae rather brittle. Color white, grayish, reddish. Lustre of cleavage surface 320 DESCRIPTIONS OP MINERALS. strong pearly and brilliant, of sides of crystals vitreous. H.=3'5-4-5. G. = 2.99. Composition. II 2 RA1 2 Oi 2 Si 2 = Silica 30*1, alumina 51.2, lime 11 *6, soda 2-6, water 4*5 = 100. B.B. whitens and fuses on the edges. Obs. Often associated with corundum and diaspora. Oc- curs in Asia Minor ; at Sterzing in the Tyrol ; in the Urals ; in Village Green, and Unionville, Pa. ; in Buncombe County, N". 0.; at Chester, Mass. Named from the Greek margarites, a pearl. Wittcoxite is near margarite. Dudleyite is an alteration product of margarite. Chloritoid. Masonite. Phyllite. Ottrelite. Monoclinic or triclinic. Cleavage basal, perfect. Also coarse foliated massive ; and in thin disseminated scales (phyllite or ottrelite). Brittle. Color dark gray, greenish, to black. Lustre of cleavage surface somewhat pearly. Composition. FeAl 6 Si + l aq= Silica 24'0, alumina 40 '5, iron protoxide 284, water 7*1 = 100. B.B. becomes darker and magnetic, but fuses with difficulty. Decomposed com- pletely by sulphuric acid. Obs. Found at Kossoibrod, Urals, with cyanite ; in Asia Minor, with emery; at St. Marcel ; Ottrez, France (Ottre- lite) ; Chester, Mass.; in Eh ode Island (Masonite) ; at Brome and Leeds, Canada. Phyllite in scales character- izes the " spangled mica slate " of Newport, R. I., and Sterling, Goshen, etc., Mass. Seybertite. Occurs in somewhat mica like, or thin foliated forms, with perfect basal cleavage, and laminae brittle, the color reddish or yellowish brown to copper-red. Analysis by Brush obtained Silica 20 24, alumina 39 '13, iron sesquioxide 3 '27, magnesia 20*84, lime 13-69, water 1'04, potash and soda T43, zirconia 0'75=100'39, giving the quantiva- lent ratio for protoxides, sesquioxides, silica, and water 6 : 9 : 5 : . From Amity, N. Y. ; Slatoust, Urals (Xanthophyllite) ; Fassa Valley (Bran- disite and Disterrite). IV. HYDROCARBON COMPOUNDS. The following are the subdivisions here used. I. SIMPLE HYDKOCABBOHS : Marsh-gas, Mineral oils, and Mineral wax. SIMPLE HYDROCARBONS. 321 II. OXYGENATED HYDROCARBONS : mostly resins. III. ASPHALTUM AND MINERAL COALS. I. SIMPLE HYDROCARBONS. Marsh-Gas. Light Carburetted Hydrogen Colorless and inodorous gas in the pure state. Inflam- mable, and burns with a yellow flame. Composition CII 4 = Carbon 75, hydrogen 25 100. Obs. This gas (mixed with more or less carbon dioxide and nitrogen) often rises in bubbles through the waters of marshes, whence its name ; and frequently it is discharged from fissures into coal mines in large quantities, constituting the fire-damp of the mine. Such natural discharges, called blowers, sometimes continue for months. It is the cause of the explosions in mines, a mixture of it with the atmo- sphere exploding on the approach of the flame of a can- dle. It destroys life both by the concussion occasioned, by the exhaustion of the atmosphere of oxygen, and by the production of carbon dioxide which takes place. The gas which issues from the oil springs or wells of Western New York (Fredonia), and Eastern Pennsylvania, is marsh-gas mixed with other vapors of the Marsh-gas series. It is used in some places for lighting houses, and even villages ; and also for other purposes where heat is required. The gas bubbling up from a marsh in Europe afforded Websky Carbon dioxide 2-97, marsh-gas 43-36, nitrogen 53-67=100. The first of these ingredients is in fact one of the more abundant results of decomposition, whetlter vegetable or animal ; and the percentage is here small because the gas is soluble in water, and because it readily enters into combinations with the earthy ingredients of plants. Petroleum. Mineral oils, varying in density from 0*60 to 0-85. Solu- ble in benzine or camphene. They consist chiefly of liquids of the Naphtha and Ethylene series. The composition of the Naphtha or Marsh-gas series is expressed by the general formula, C n H 2n + 2, of which Marsh-gas is the first or lowest term ; and that of the Ethylene series by the for- mula, C n H 2n =rCarbon 85'71, hydrogen 14-29-100. The oils vary greatly in density from the lightest naphtha, too DESCRIPTIONS OP MINERALS. inflammable for use in lighting, to thick viscid fluids ; and thence they pass by insensible gradations into asphaltum or solid bitumen. The Marsh-gas series contains also gases, of the composition C 2 H 6 and C 3 H 8 and these, in addition to Marsh-gas, often exist in connection with petroleum. Petroleum occurs in rocks of all ages, from the Lower Silurian to the most recent ; in limestones, the more com- pact sandstones, and shales ; but it is mostly obtained from large cavities or caverns existing among the earth's strata. Black shales and much bituminous coal afford it abundantly when they are heated. But the oil obtained is not present in these rocks, for when the rocks are treated with benzine, the benzine takes up little or none ; instead, the rocks con- tain an insoluble hydrocarbon, which yields the oil when heat is applied. In the United States the oil, or the hydrocarbon which yields it, has been observed in beds of the Lower and Upper Silurian, Devonian, Carboniferous, Triassic, Cretaceous, and Tertiary eras. Surface oil springs also occur in many places, as at Cuba, Alleghany County, N. Y., called Seneca Oil Spring ; and on a large scale in Santa Barbara, Southern California ; at Rangoon in Burmah, where there are about 100 wells ; on the peninsula of Apcheron, on the Caspian, and elsewhere. Pliny mentions the oil spring of Agrigen- tum, Sicily, and says that the liquid was collected and used for burning in lamps, as a substitute for oil. Moreover he distinguishes the oil from the lighter and more combustible naphtha, a locality of which about the sources of the Indus, ^n Parthia," he mentions. Petroleum is obtained chiefly at the present time from more or less deeply-seated subterranean chambers or cavities among the rock "strata, reached by boring. Being under pressure of gas associated with it, and also, in many cases, that also of water, it rises to the surface in the boring, and sometimes makes a "spouting" well. As early as 1833, Hildreth mentioned the discharge of oil with the waters of the salt wells of the Little Kanawha valley ; and speaks also of a well near Marietta, Ohio, which threw out at one time, he says, 50 to 60 gallons of oil at " each eruption." The mineral oil of the rocks has been formed through the decomposition of animal and vegetable substances. From the nature of the rocks which most abound in the species of hydrocarbons that yield oil, it is evident that SIMPLE HYDROCARBONS. the rock material was in the state of a fine mud ; that through this mud much vegetable or animal matter was distributed, almost in the condition of an emulsion ; that the stratum of this mud becoming afterward overlaid by other strata, the decomposition of vegetable or animal mat- ter went forward without the presence of atmospheric air, or with only very little of it. Under such circumstances either vegetable material or animal oils might be converted, as chemists have shown, into mineral oil. Dry wood con- sists approximately (excluding the ash and nitrogen) of 6 atoms of carbon to 9 of hydrogen, and 4 of oxygen. If now all the oxygen of the Avood combines with a part of the car- bon to form carbonic acid, and this 2 C0 2 , thus made, is re- moved, there will be left C 4 II 9 ; twice this, C 8 H 18 , is the formula of a compound of the Marsh-gas or Naphtha series. Again animal oils, by decomposition under similar cir- cumstances, produce like results. Removing from oleic acid its oxygen, 2 , and 1 of carbon together equivalent to 1 of carbonic acid there is left C 17 H ?4 , which is an oil of the Ethylene series ; and margaric acid would leave, in the same way, C 16 H 34 , or a combination of oils of the Marsh-gas or Naphtha series. Warren and Storer have obtained from the destructive distillation of a fish-oil, after its saponifica- tion by lime, several compounds of the Marsh-gas series, be- sides others of the Ethylene and Benzole series. The de- compositions in nature may not have been as simple as those in the above illustrations, yet the facts warrant the infer- ence that the oils may have been derived either from vege- table or animal matters. Fossil fishes are often found abun- dantly in black oil-yielding shales, and Dr. Newberry has suggested that fish-oil may be the most abundant source of the oil and the oil-yielding hydrocarbons. The oil which is collected in great cavities among the earth's strata, as in Western Pennsylvania, is believed by most writers on the subject to have come from underlying rocks, such as the black oil-yielding shales. The heat pro- duced in the rocks by the friction attending movements and uplifts, is supposed to have been sufficient to have made the oil from the hydrocarbon of the carbonaceous shale or other rock, and co have caused it to ascend among the strata to the cavities where it was condensed, and now is found by boring. The oils, exposed to the air and wind, undergo change in 324 DESCRIPTIONS OF MINERALS. three ways. First : the lighter naphthas evaporate, leaving the denser oils behind ; and, ultimately, the viscid bitumens, or else paraffin, according as paraffin is present or not in the native oil. At the naphtha island of Tschelekan in Per- sia, there are large quantities of Neft-yil, as it is called, which is nearly pure paraffin. The hot climate of the Cas- pian is favorable for such a result. Secondly: ther emay be a loss of hydrogen from its combination with the oxygen of the atmosphere to form water, which escapes. Thus the oils of the Naphtha series may change into those of the Ethy- lene or Benzole series. Thirdly : there may be an oxidation of the hydrocarbon of the oils, producing asphaltum or more coal-like substances, like albertite. The word naphtha is from the Persian, nafata, to exude ; and petroleum from the Greek, petros, rock, and the Latin, oleum, oil. Hachettite. Mountain Tallow, Hatchetine. Like soft wax in appearance and hardness, of a yellowish- white to greenish -yellow color. Composition. Related to paraffin. From the coal-measures of Glamorganshire in Wales. Ozocerite is like wax or spermaceti in consistence. Soluble in ether. The original was from Moldavia. Along with another wax -like sub- stance, called Urpethite, it constitutes trie "mineral wax of Urpeth Colliery." Zietrisikite is like beeswax, and is insoluble in ether ; from Moldavia, Elaterite. Mineral Caoutchouc. Elastic Bitumen. In soft flexible masses, somewhat resembling caoutchouc or India rubber. Color brownish-black ; sometimes orange- red by transmitted light. G. =0'9-r25. Composition: Car- bon 85*5, hydrogen 13 '3 = 98 -8. It burns readily with a yel- low flame and bituminous odor. Obs. From a lead mine in Derbyshire, England, and a coal mine at Montrelais. It has been found at Woodbury, Ct., in a bituminous limestone. Fichtelite and Hartite are crystallized hydrocarbons, of the Cam- phene series. Branchite, Dinite, and Ixolyte are related to Hartite. Konlite, Naphthalin, and Idrialite are native species of the Benzole series. Aragotite, from California, is near Idrialite. OXYGENATED HYDROCARBONS. 325 II. OXYGENATED HYDROCARBONS. Amber. In irregular masses. Color yellow, sometimes brownish or whitish ; lustre resinous. Transparent to translucent. H. = 2-2-o. G.= l-18. Electric by friction. Amber is not a simple resin, but consists mainly (85 to 90 percent.) of a resin which resists all solvents, called Suc- cinite, and two other resins soluble in alcohol and ether, besides an oil, and 2% to G per cent, of Succinic acid. Obs. Occurs in the loose deposits along coasts, especially Tertiary strata, in masses from a very small size to that of a man's head. In the Koyal Museum at Berlin, there is a mass weighing 18 pounds. On the Baltic coast it is most abundant, especially between Konigsberg and Memel. It is met with at one place in a bed of bituminous coal ; it also occurs on the Adriatic ; in Poland ; on the Sicilian coast near Catania ; in France near Paris, in clay ; in China. It has been found in the United States, at Gay Head, Martha's Vineyard ; Camden, N. J. ; and at Cape Sable, near the Magothy River, in Maryland. It is supposed, with good reason, to be a vegetable resin which has undergone some change while inhumed, a part of which is due to acids of sulphur proceeding from decom- posing pyrites or some other source. It often contains in- sects, and specimens of this kind are so highly prized as frequently to be imitated for the shops. Some of the insects appear evidently to have struggled after being entangled in the then viscous resin, and occasionally a leg or a wing is found some distance from the body, having been detached in the struggle for escape. Amber is the electron of the Greeks ; from its becoming electric so readily Avhen rubbed, it gave the name electricity to science. It was also called succinum, from the Greek succum, juice, because of its supposed vegetable origin. It admits of a good polish and is used for ornamental purposes, though not very much esteemed, as it is wanting in hardness and brilliancy of lustre, and moreover is easily imitated. It is much valued in Turkey for mouth-pieces to pipes. Copalite, or Mineral Copal, Walchowite, Ambrite (the New Zealand resin), Euosmite, Scleretinite, Middletote are some of the names of other fossil resins ; Geocerite, and Geomyricite, of wax -like oxygenated species ; Guyaquittite, BathvUlite, Torbanite, lonite (from lone valley, 326 DESCRIPTIONS OF MINERALS. California), of species not resinous in lustre ; Tasmanite and Dysodile, of kinds containing several per cent, of sulphur. Wollongongite, from Australia, is black, and looks like cannel coal. III. ASPHALTUM AND MINERAL COALS. Asphaltum. Amorphous and pitch-like. Burning with a bright flame and melting at 90 to 100 F. Soluble mostly or wholly in camphene. It is a mixture of hydrocarbons, part of which are oxygenated. Obs. Asphaltum is met with abundantly on the shores of the Dead Sea, and in the neighborhood of the Caspian. A remarkable locality occurs on the island of Trinidad, where there is a lake of it about a mile and half in circumference. The bitumen is solid and cold near the shores; but gradu- ally increases in temperature and softness toward the cen- tre, where it is boiling. The appearance of the solidified bitumen is as if the whole surface had boiled up in large bubbles and then suddenly cooled. The ascent to the lake from the sea, a distance of three quarters of a mile, is cov- ered with the hardened pitch, on which trees and vegetation flourish, and here and there, about Point La Braye, the masses of pitch look like black rocks among the foliage. It occurs also in South America about similar lakes in Peru, where it is used for pitching boats ; and in California on the coast of Santa Barbara. Large deposits occur in sand- stone in Albania. It is also found in Derbyshire, and with quartz and fluor in granite in Cornwall, and at many other places. Albertite. Coal-like in hardness, but little soluble in camphene, and only imperfectly fusing when heated ; but having the lustre of asphaltum, and softens a little in boiling water. H. 1-2. G.= 1-097. Fills fissures in the Subcarboniferous rocks near Hills- borough, Nova Scotia, and supposed to have been derived from the hydrocarbon of the adjoining rock, and to have been oxidized at the time it was formed and filled the fissure. Orahamite is a related material from West Virginia, 20 miles south of Parkersburg. ^H. =2. G. ^t'143. Soluble mostly in camphene, but melts only imperfectly. An analysis afforded carbon 76 '45, hy- drogen 7 '82, oxygen (with traces of nitrogen) 13 '40, ash 2 '26 =100, MINERAL COAL. 327 MINERAL COAL. Massive. Color black or brown ; opaque. Brittle or im- perfectly sectile. H. =0-5-2-5. G. = 1 '2-1-80. Composition. Carbon, with some oxygen and hydrogen, more or less moisture, and traces also of nitrogen, besides some earthy mineral which constitutes the ash. The car- bon, or part of it, is in chemical combination with the hydrogen and oxygen. Coals differ in the amount of volatile ingredients given off when heated. These ingredients are moisture, and hy- drocarbon oils and gas, derived from the same class of insoluble hydrocarbons that is the source of the oil of shales and other rocks. VARIETIES. 1. Anthracite. Anthracite (called also (/lance coal and stone coal) has a high lustre, and is often iridescent. It is quite compact and hard, and has a specific gravity from 1'3 to 1*75. It usually contains 80 to 93 per cent, of carbon, with 4 to 7 of volatile matter ; the rest consisting of earthy impurities. Burns with a feeble blue flame. Those yielding the most volatile ingredients are called free-burning anthracite. 2. Bituminous Coal. Bituminous coal varies much in the amount of oil, coal-tar, or gas it yields when heated; and there is a gradual passage in its varieties through semi- anthracite to anthracite. It is of a black color, with the powder black, but it is softer than anthracite, and less lustrous. The specific gravity does not exceed 1*5. The volatile ingredients constitute usually between 20 and 40 per cent. Caking Coal includes that part of bituminous coal which softens when heated and becomes viscid, so that adjoining pieces unite into a solid mass. It burns readily with a lively yellow flame, but requires frequent stirring to prevent its agglutinating, and so clogging the fire. Non-caking coal resembles the caking in appearance, but does not soften and cake. The chemical difference between caking and non- caking coal is not understood. 3. Cannel Coal is very compact and even in texture, with little lustre, and breaks with a large conchoidal fracture. It takes fire readily, and burns without melting to a clear yel- 328 DESCRIPTIONS OP MINERALS. low flame, and has hence been used as candles whence the name. It affords when heated a large amount of mineral oil, and may be used for its production. The volatile in- gredients sometimes amount to 50 or 60 per cent. It is often made into inkstands, snuff-boxes, and other similar articles. 4. Brown Coal usually has a brownish-black color, and contains 15 to 20 per cent, of oxygen, but much resembles in appearance bituminous coal. The term brown coal is ap- plied generally to any coal more recent in origin than the era of the great coal beds of the world. The name lignite has sometimes the same general application, though without strict propriety. Lignite is the part of brown coal which has the woody structure still apparent. Jet resembles cannel coal, but is harder, of a deeper black color, and has a much higher lustre. It receives a brilliant polish, and is set in jewelry. It is the Gagates of Diosco- rides and Pliny, a name derived from the river Gagas, in Syria, near the mouth of which it was found, and the origin of the term jet now in use. Native Coke resembles somewhat artificial coke, but is more compact, and some varieties of it afford a consider- able amount of bitumen. It occurs at the Edgehill mines near Richmond, Virginia, according to Genth, who attri- butes its origin to the action of a trap eruption on bitumi- nous coal. It is now well established that mineral coal is mainly of vegetable origin, and that the accumulations out of which the coal beds were made were very similar in character, though not in kinds of plants, to the peat beds of the pres- ent day. Peat is vegetation which has undergone, in part, the change to coal ; and in some cases it has become brown coal. The conditions of change are somewhat different from those of the beds of good coal, since, in the case of the peat, the air has access, while in that of the coal the air was more or less excluded by overlying strata ; and the more perfect the exclusion, other things equal, the better the coal. As the composition of mineral coal is closely related to that of mineral oils", the explanation of the origin of the latter, given on page 323, suffices to illustrate also the origin of the former. With a less complete exclusion of the air, oxygen- ated hydrocarbon compounds, like coal, would be a natural result. MINERAL COAL. 329 The following are a few analyses of coals, the moisture excluded: Carbon. Hydr. Oxyg. Nitr. Sulph. Ash. 1 Anthracite Pennsylvania 90 45 2-43 2-45 4-67 0, Anthracite Pennsylvania 92 59 263 1-61 092 225 3 Anthracite, South Wales . . 92 56 3 33 2-53 1 58 4 5 6 7 8 Caking Coal, Kentucky Caking Coal, Nelsonville, O. Caking Coal, South Wales. . Caking Coal, Northumberl'd Non-caking, Kentucky 74-45 73-80 82-56 78'69 77-89 4-93 579 536 6-00 5 42 1308 16-58 8-22 10-07 12-57 103 1-52 1-65 2-37 1-82 091 0-41 075 1-51 3-00 500 190 1-46 1-36 200 9 Non-caking " Black Coal," ) Ind ) 82-70 4-77 939 1-62 0-45 1-07 10 11 19 Non-caking, Briar Hill, O. . Non-caking, S. Staffordshire Non-cakin " Scotland . . . 78-94 7640 76'08 5-92 462 5 -81 11-50 17-43 13 33 1-58 209 0-56 0-55 1-23 1-45 155 1-96 13 14 Cannel Coal, Breckenridge . Cannel Coal ^^igan 68-13 8007 6-49 5 53 5-83 8 10 2-27 2-12 2-48 1-50 1230 2-70 15 16 Cannel Coal, " Torbanite". Albertite Nova Scotia 6402 86*04 8-90 8 '96 5-66 1-97 055 293 050 tTace 2032 o-io 17 Brown Coal Bovey 66-31 5 63 22-86 0-57 2-36 2-27 is Brown Coal Wittenberg. . . 64-07 503 27-55 335 19 Peat light brown (imperfect) 50'86 5 -80 42-57 0*77 30 Peat dark bcown 59-47 6-52 31 51 2 51 ?r1 Peat black 59-70 5-70 3304 1 56 00, Peat black 59-71 5 27 32-07 2-59 The coal, No. 4, from "Roberts' Seam," Muhlenburg County, Ken- tucky, has specific gravity =1 26 ; No. 9, from " Wolf Hill," Daviess County, Indiana, has specific gravity =1 "275. No. 13, the Breckenridge cannel, of Hancock County, Kentucky, consists, when the ash is excluded, of Carbon 82 '36, hydrogen 7 '84, oxygen 7 05, nitrogen 2 75, and the Bog-head cannel of Scotland, called also torbanite, contains Carbon 8039, hydrogen 11-19, oxygen 7 '11, ni trogen 1*31. The " Mineral Charcoal " of coal beds differs little in composition from ordinary bituminous coal ; there is less hydrogen and oxygen. Rowney obtained, for that of Glasgow and Fifeshire, Carbon 82 "97, 74-71 ; hydrogen 3 34, 2 74; oxygen 759, 767 ; ash 6'08, I486. The nitrogen is included with the oxygen ; it was 0'75 in the Glasgow char- coal. Exclusive of the ash, the composition is Carbon 88/36, 87*78 ; hydrogen 356, 321; oxygen 7 '28, 9' 01. It has a fibrous look, and occurs covering the surfaces between layers of coal, and has been ob- served in coal of all ages. It is soft and soils the fingers like char- coal ; one variety of it is a dry powder. 330 DESCRIPTIONS OF MINERALS. The following are average results, from many analyses : Vol. Fixed Nos. Sp. gr. com- Car- Ash. Analysis. bust. bon. 1 Pennsylvania anthracites. . . -j 7 16 1-59-1-61 1-39-1 -GO 3-92 5-70 89-77 88-23 6-31 6-07 Johnson. Geol. Survey. 2 Pennsylvania semi-anthra- 1 cites f 11 1-33-1-45 9-98 82-86 7-16 Geol. Survey. 3 Pennsylvania semi-bitunii- 1 nous . f 6 1-30-1-41 16-85 72-95 10-20 Johnson. 4 Maryland semi-bituminous... 9 1-30-1-43 1550 7403 10-47 ( Johnson and j Geol. Survey. 5 Pennsylvania bituminous 10 28-35 65-18 6-47 Johnson. 6 Virginia bituminous . . . 11 i 29-1-45 29'88 59-06 11-06 Johnson. 7 Ohio bituminous 142 1-24-1-47 35-24 60-26 4-50 Wormley. g 126 1' 1Q 1 ' 41 43-20 53-47 3'33 Cox q Illinois bituminous . . . 50 1-21 1-35 31 90 62-44 5'66 Blaney. 10 Iowa bituminous . ... 59 43-02 6-82 Emery. The ordinary impurities of coal, making up its ash, are silica, a little potash and soda, and sometimes alumina, with often oxide of iron, derived usually from sulphide of iron ; besides, in the less pure kinds, more or less clay or shale. The amount of ash does not ordina- rily exceed 6 per cent., but it is sometimes 80 per cent. ; and rarely it is less than 2 per cent. When not over 3 or 4 per cent, the whole may have come from the plants which contributed the most of the material of the coal, since the Lycopods have much alumina in the ash, and the Equiseta much silica. There is present in most coal traces of sulphide of iron (pyrite), suf- ficient to give sulphur fumes to the gases from the burning coal, and sometimes enough to make the coal valueless in metallurgical opera- tions. Some thin layers are occasionally full of concretionary pyrite. The sulphur was derived from the plants or from animal life in the waters. Sulphur also occurs, in some coal beds, as a constituent of a resinous substance ; and Wormley has shown that part of the sulphur in the Ohio coals is in some analogous state, there being not iron enough present to take the whole into combination. The average amount of ash in eighty-eight coals from the southern half of Ohio, according to Wormley, is 4'718 per cent.; in sixty-six coals from the northern half, 5 '120 ; in all, from both regions, 4 '891 ; or, omitting ten, having more than ten per cent, of ash, the average is 4"->8. In eleven Ohio cannels, the average amount of ash was 12'827. The moisture in the Ohio coals, according to the analyses of Wormley, varies from T10 to 910 per cent, of the coal. Mineral coal occurs in extensive beds or layers, interstratified with different rock strata. The associate rocks are usually clay shales (or slaty beds) and sandstones ; and the sandstones are occasionally coarse grit rocks or conglomerates. There are sometimes also beds of lime- stone alternating with the other deposits. Coal beds vary in thickness from a fraction of an inch to 40 feet. The thickness of a bed may increase or diminish much in the course of a few miles, or the coalmay become too shaly to work. MINERAL COAL. 331 The areas of the "coal-measures" of the Carboniferous era, in the United States, are as follows : 1. A small area in Rhode Island, continued northward into Massa- chusetts. 2. A large area in Nova Scotia and New Brunswick, stretching east- ward and westward from the head of the Bay of Fundy. These two areas are now separated ; but it is probable that they were once united along the region, now submerged, of the Bay of Fundy and Massachusetts Bay. 3. The Alleghany Region, which commences at the north on the southern borders of New York, and stretches south westward across Pennsylvania, West Virginia, and Tennessee to Alabama, and west- ward over part of Eastern Ohio, Kentucky, Tennessee, and a small portion of Mississippi. To the north, the Cincinnati " uplift," or the Silurian area extending from Lake Erie over Cincinnati to Ten- nessee, forms the western boundary. 4. The Michigan coal area, an isolated area wholly confined within the lower peninsula of Michigan. 5. The Eastern Interior area, covering nearly two-thirds of Illinois, and parts of Indiana and Kentucky. 6. The Western Interior area, covering a large part of Missouri, and extending north into Iowa, and South, with interruptions, through Arkansas into Texas, and west into Kansas and Nebraska. The Illinois and Missouri areas are connected now only through the underlying Subcarbonif erous rocks of the age ; but it is probable that formerly the coal fields stretched across the channel of the Missis- sippi, and that the present separation is due to erosion along the valley. Rocks of the Carboniferous period extend over large portions of the Rocky Mountain area, but they are mostly limestones, and are barren of coal. The extent of the coal -bearing area of these Carboniferous regions is approximately as follows : Rhode Island area 500 square miles. Alleghany area 59,000 square miles. Michigan area 6,700 square miles. Illinois, Indiana, West Kentucky 47,000 square miles. Missouri, Iowa, Kansas, Arkansas, Texas 78,000 square miles. Nova Scotia and New Brunswick 18,000 square miles. The whole area in the United States is over 190,000 square miles, and in North America about 208,000. Of the 190,000 square miles, perhaps 120,000 have workable beds of coal. Anthracite is the coal of Rhode Island, and of the areas in Central Pennsylvania, from the Pottsville or Schuylkill coal field to the Lacka- wanna field, while the coal of Pittsburg, and of all the great coal- fields of the Interior basin, is bituminous, excepting a small area in Arkansas. Anthracite belongs especially to regions of upturned rocks, and bituminous coal to those where the beds are little disturbed. In the area between the anthracite region of Central Pennsylvania and the bituminous of Western, and farther south, the coal is semi- bituminous, as in Broad Top, Pennsylvania, and the Cumberland coal field in Western Maryland, the volatile matters yielded by it being 15 332 DESCRIPTIONS OP MINERALS. to 20 per cent. The more western parts of the anthracite coal fields afford the free-burning anthracite, or semi-anthracite, as at Trevor- ton, Shamokin, and Birch Creek. The coal-formation of the Carboniferous age in Europe has great thickness of rocks and coal in Great Britain, much less in Spain, France, and Germany, and a large surface, with little thickness of coal, in Russia. It exists, also, and includes workable coal-beds, in China, and also in India and Australia ; but part of the formation in these latter regions may prove to be Permian. No coal of this era has yet been found in South America, Africa, or Asiatic Russia. The pro- portion of coal beds to area in different parts of Europe has teen stated as follows : in France, l-100th of the surface ; in Spain, l-50th; in Belgium, l-20th ; in Great Britain, 1-lOth. But, while the coal area in Great Britain is about 12,000 square miles, that of Spain is 4,000, that of France about 2,000, and that of Belgium 518. Mineral coal of later age than the true Carboniferous era occurs in various parts of the world. Triassic or Jurassic coal, of the bitumi- nous variety, occurs in thick workable beds in the vicinity of Rich- mond, Virginia, and also in the Deep River and Dan River regions in North Carolina ; and it constitutes very valuable and extensive beds also in India. In England, at Brora in Sutherlandshire, there is a bed of Jurassic coal. Coal of the Cretaceous and Tertiary eras constitutes important beds in various parts of the Rocky Mountain region, in the vicinity of the Pacific Railroad and elsewhere. Some of the prominent localities are : In Utah, at Evanston and Coalville (in the valley of Weber River), etc.; in Wyoming, at Carbon, 140 miles from Cheyenne ; at Hallville, 142 miles farther west ; at Black Butte Station, on Bitter Creek ; on Bear River, etc. ; in the Uintah Basin, near Brush Creek, 6 miles from Green River ; in Colorado, at Golden City, 15 miles west of Denver, on Ralston Creek, Coal Creek, S. Boulder Creek and elsewhere ; in New Mexico, at the Old Placer Mines in the San Lazaro Mountains, etc. The coal is of the bitumi- nous or semibituminous kind, related to brown coal, and is often im properly called lignite. That of Evanston (where the bed is 26 feet thick) afforded Prof. P. Frazier, Jr. , 37-38 per cent, of volatile sub- stances, 5-6 of water, 7-8 of ash, and 49-50 of fixed carbon. At the Old Placer Mines, New Mexico, there is anthracite, according to Dr. J. LeConte, affording 88 to 91 per cent, of fixed carbon ; specimens from there, analyzed by Frazier, were semibituminous, affording 68-70 per cent, of fixed carbon, 20 per cent, of volatile substances, and about 3 per cent, of water. The region of the Old Placer Mines is one of upturned and altered rocks, like the anthracite region of Pennsyl- vania. Other similar beds occur toward the Pacific coast, the most valuable of them in Washington Territory, Seattle and Belli ngham Bay, and on Vancouver and adjacent islands in British Columbia. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 333 I. CATALOGUE OP AMERICAN LOCALL TIES OF MINERALS. THE following catalogue of American localities of minerals is intro- duced as a Supplement to the Descriptions of Minerals. Its object is to aid the mineralogical tourist in selecting his routes and arranging the plan of his journeys. Only important localities, affording cabinet specimens, are in general included ; and the names of those miner ah which are obtainable in good specimens are distinguished by italics. When a name is not italicized the mineral occurs only sparingly or of poor quality. When the specimens to be procured are remarkably good, an e'xclamation mark (!) is added, or two of those marks (I !) when the specimens are quite unique. MAINE. ALBANY. Beryl! green and black tourmaline, feldspar, rose quartz, rutile. AROOSTOOK. Red hematite. AUBURN. Lepidolite, hebronite, green tourmaline. BATH. Vesuvianite, garnet, magnetite, graphite. BETHEL. Cinnamon garnet, calcite, sphene, beryl, pyroxene, horn- blende, epidote, graphite, talc, pyrite, arsenopyrite, magnetite, wad. BINGHAM. Massive pyrite, galenite, blende, andalusite. BLUE HILL BAY. Arsenical iron, molybdenite! galenite, apatite! fluoritef black tourmaline (Long Cove), black oxide of manganese (Osgood's farm), rhodonite, bog manganese, wolframite. BOWDOIN. Rose quartz. BOWDOINHAM. Beryl, molybdenite. BRUNSWICK. Green mica, garnet ! black tourmaline ! molybdenite, epidote, calcite, muscomte, feldspar, beryl. BUCKFIELD. Garnet (estates of Waterman and Lowe), muscomte! tourmaline ! magnetite. CAMDAGE FARM. (Near the tide mills), molybdenite, wolframite. CAMDEN. Macle, galenite, epidote, black tourmaline, pyrite, talc, magnetite. CARMEL (Penobscot Co.) Stibnite, pyrite, made. CORINN A. Pyrite, arsenopyrite. DEER ISLE. Serpentine, verd-antique, asbestus, diallage. DEXTER. Galenite, pyrite, blende, chalcopyrite, green talc. DIXFIELD. Native copperas, graphite. EAST WOODSTOCK. Muscovite. FARMINGTON. (Norton's Ledge), pyrite, graphite, garnet, staurolite. FREEPORT. Rose quartz, garnet, feldspar, scapolite, graphite, mu* tovite. FRYEBURG. Garnet, beryl. GEORGETOWN. (Parker's Island), beryl! black tourmaline. 334 SUPPLEMENT TO DESCRIPTIONSJOF SPECIES. GREENWOOD. Graphite, black manganese, "beryl! arsenopyrite, cassiterite, mica, rose quartz, garnet, corundum, albite, zircon, molyb- denite, magnetite, copperas. HEBRON. Cassiterite, arsenopyrite, idocrase, lepidolite, hebronite, rubellite ! indicolite, green tourmaline, mica, beryl, apatite, albite, chil- drenite, cookeite. JEWELL'S ISLAND. Pyrite. KATAHDIN IRON WORKS. Bog-iron ore, pyrite, magnetite, quartz. LITCHFIELD. Sodalite, cancrinite, elceolite, zircon, spodumene, mus- covite, pyrrliotite. LUBEC LEAD MINES. Galenite, cJialcopyrite, blende. MACHIASPORT. Jasper, epidote, laumontite. MADAWASKA SETTLEMENTS. Vivianite. MINOT. Beryl, smoky quartz. MONMOUTH. Actinolite, apatite, elceolite, zircon, staurolite, plumose mica, beryl, rutile. MT. ABRAHAM. Andalusite, staurolite. NORWAY. Chrysoberyl! molybdenite, beryl, rose quartz, orthoclase, cinnamon garnet. ORR'S ISLAND. Steatite, garnet, andalusite. OXFORD. Garnet, beryl, apatite, wad, zircon, muscovite, orthoclase. PARIS. Green! red! black, and blue tourmaline! mica! lepidolite! feldspar, albite, quartz crystals! rose quartz, cassiterite, amblygonite, zircon, brookite, beryl, smoky quartz, spodumene, cookeite, leucopy- rite. PARSONSFIELD. Vesuvianite f yellow garnet, pargasite, adularia, scapolite, galenite, blende, chalcopyrite. PERU. Crystallized pyrite. PHIPPSBURG. Yellow garnet ! manganesian garnet, vesuvianite, par- gasite, axinite, laumontite ! chabazite, an ore of cerium ? POLAND. Vesuvianite, smoky quartz, cinnamon garnet. PORTLAND. Prehnite, actinolite, garnet, epidote, amethyst, calcite. POWNAL. Black tourmaline, feldspar, scapolite, pyrite, actinolite, apatite, rose quartz. RAYMOND. Magnetite, scapolite, pyroxene, lepidolite, tremolite, horn- blende, epidote, orthoclase, yellow garnet, pyrite, vesuvianite. ROCKLAND. Hematite, tremolite, quartz, wad, talc. RUMFORD. Yellow garnet, vesuvianite, pyroxene, apatite, scapolite. RUTLAND. Allanite. SANDY RIVER. Auriferous sand. SANFORD, York Co. Vesuvianite f albite, calcite, molybdenite, epi- dote, black tourmaline, labradorite. SEARSMONT. Andalusite, tourmaline. SOUTH BERWICK. Macle. STANDISH. Columbite ! STREAKED MOUNTAIN. Beryl! black tourmaline, mica, garnet. THOM ASTON. Calcite, tremolite, Jiornblende, sphene, arsenical iron (Owl's Head), black manganese (Dodge's Mountain), thomsonite, talc, blende, pyrite, galenite. TOPSHAM. Quartz, galenite, blende, tungstite? beryl, apatite, molybdenite, columbite. WALES. ; Axinite in boulder, alum, copperas. WATERVILLE. Crystallized pyrite. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 335 WINDHAM (near the bridge). Staurolite, spodumene, garnet, beryl, amethyst, cyanite, tourmaline. WINSLOW. Cassiterite. WINTHROP.- -Staurolite, pyrite, hornblende, garnet, copperas. WOODSTOCK. Graphite, hematite, prehnite, epidote, calcite. YORK. Beryl, vivianite, oxide of manganese. NEW HAMPSHIRE. ACWORTH. Beryl!! mica! tourmaline, orthodase, albite, rose quartz, columbitef cyanite, autunite. ALSTEAD. Mica! ! albite , black tourmaline, molybdenite, andalu- site, Staurolite. AMHERST. Vesumanite, yellow garnet, pargasite, calcite, amethyst. BARTLETT. Magnetite, hematite, smoky quartz. BATH. Galenite, chalcopyrite. BEDFORD. Tremolite, epidote, graphite, mica, tourmaline, alum, quartz. BELLOWS FALLS. Cyanite, Staurolite, wavellite. BRISTOL. Graphite. CAMPTON. Beryl ! CANAAN. Gold in pyrite, garnet. CHARLESTON. Staurolite made, andalusite made, bog-iron ore, prehnite, cyanite. CORNISH. Stibnite, tetrahedrite, rutUein quartz! (rare), Staurolite. CROYDEN. lolite! chalcopyrite, pyrite, pyrrhotite, blende. ENFIELD. Gold, galenite. Staurolite, green quartz. FRANCESTON. Soapstonc, arsenopyrite, quartz crystals. FRANCONIA. Hornblende, Staurolite ! epidote ! zoisite, hematite, magnetite, black and red manganesian garnets, arsenopyrite (danaite), chalcopyrite, molybdenite, prehnite, green quartz, malachite, azurite. GILFORD (Gunstock Mt.) Magnetic iron ore, native "lodestone." GILMANTOWN. Tremolite, epidote, muscovite, tourmaline, limonite, red and yellow quartz crystals. GOSHEN. Graphite, black tourmaline. GRAFTON. Mica! (extensively quarried at Glass Hill, 2 m. S. of Orange Summit), albite ! blue, green, and yellow beryls ! (i m. S. of O. Summit), tourmaline, garnets, triphylite, apatite, fluorite. GRANTHAM. Gray Staurolite! GROTON. Arsenopyrite, blue beryl, muscovite crystals. HANOVER. Garnet, black tourmaline, quartz, cyanite, labradorite t epidote, anorthite. HAVERHILL. Garnet! arsenopyrite, native arsenic, galenite, blende, pyrite, chalcopyrite, magnetite, marcasite, steatite. HILLSBORO' (Campbell's Mountain). Graphite. HINSDALE. Rhodonite, black oxide of manganese, molybdenite, in- dicolite, black tourmaline. JACKSON. Drusy quartz, tin ore, arsenopyrite, native arsenic, fluo rite, apatite, magnetite, molybdenite, wolframite, chalcopyrite. JAFFREY (Monadnock Mt.) Cyanite, limonite. KEENE. Graphite, soapstone, milky quartz, rose quartz. LANDAFF. Molybdenite, lead and iron ores. 336 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. LEBANON. Bog-iron ore, arsenopyrite, galenite, magnetite, pyrito. LISBON. Staurolite, black and red garnets, magnetite, hornblende, epidote, zoisite, hematite, arsenopyrite, galenite, gold, ankerite. LITTLETON. Ankerite, gold, bornite, chalcopyrite, malachite, me- naccanite, chlorite. LYMAN. Gold, arsenopyrite, ankerite, dolomite, galenite, pyrite, copper, pyrrhotite. LYME. Cyanite (N. W. part), Hack tourmaline, rutile, pyrite, chal- copyrite (E. of E. village), stibnite, molybdenite, cassiterite. MADISON. Galenite, blende, chalcopyrite, limonite. MERRIMACK. Rutile! (in gneiss nodules in granite vein). MlDDLETO WN. EutiU. MONADNOCK MOUNTAIN. Andalusite, hornblende, garnet, graphite, tourmaline, orthoclase. MOOSILAUKE MT. Tourmaline. MOULTONBOROUGH (Red Hill). Hornblende, bog ore, pyrite, tour- maline. NEWINGTON. Garnet, tourmaline. NEW LONDON. Beryl, molybdenite, muscovite crystals. NEWPORT. Molybdenite . ORANGE. Blue beryls! Orange Summit, chrysoberyl, mica(W. side of mountain), apatite, galenite, limonite. ORFORD. Brown tourmaline (now obtained with difficulty), steatite, rutile, cyanite, brown iron ore, native copper, malachite, galenite, garnet, graphite, molybdenite, pyrrhotite, melaconite, chalcocite, ripi- dolite. PELHAM. Steatite. PIERMONT. Micaceous iron, barite, green, white, and brown mica, apatite, titanic iron. PLYMOUTH. Columbite, beryl. RICHMOND. lolite! rutile, steatite, pyrite, anthophyllite, talc. RYE. Chiastolite. SADDLEBACK MT. Black tourmaline, garnet, spinel. SHELBURNE. Galenite, black blende, chalcopyrite, pyrite, pyroluslte. SPRINGFIELD. Beryls (very large, eight inches diameter), manga- nesian garnets ! black tourmaline ! in mica slate, albite, mica. SULLIVAN. Tourmaline (black) in quartz, beryl. SURREY. Amethyst, calcite, galenite, limonite, tourmaline. TAMWORTH (near White Pond). Galenite. UNITY (estate of James Neal). Copper and iron pyrites, chlorophyl- lite, green mica, radiated actinolite, garnet, titaniferous iron ore, mag- netite, tourmaline. WALPOLE (near Bellows Falls). Made, staurolite, mica, graphite. WAR E. Graphite. WARREN. Chalcopyrite, blende, epidote, quartz, pyrite, tremolite, galenite, rutile, talc, molybdenite, cinnamon stone! pyroxene, horn- blende, beryl, cyanite, tourmaline (massive) vesuvianite. WATER VILLE. Labradorite, chrysolite. WESTMORELAND (south part). Molybdenite! apatite! blue feldspar, "bog manganese (north village), quartz, fluorite, chalcopyrite, molybdite. WHITE MTS. (Notch near the "Crawford House"). Green octa- hedral fluorite, quartz crystals, black tourmaline, chiastolite, beryl, calcite, amethyst, amazon-stone. CATALOGUE OF AMERICAN LOCALITIES OP MINERALS. 337 WILMOT. Beryl. WINCHESTER. Pyrolusite, rhodonite, rhodochrosite, psilomelane, magnetite, granular quartz, spodumene. VERMONT. ADDTSON. Iron sand, pyrite. ATHENS. Steatite, rhomb spar, actinolite, garnet. BALTIMORE. Serpentine, pyrite ! BELVIDERE. Steatite, chlorite. BENNINGTON. Pyrolusite, brown iron ore, pipe clay, yellow ochre. BERKSHIRE. Epidote, hematite, magnetite. BETHEL. Actinolite! talc, chlorite, octahedral iron, rutile, brown spar in steatite. BRANDON. Braunite, pyrolusite, psilomelane, limonite, lignite, kaolinite, statuary marble ; graphite, chalcopyrite. BRATTLEBOROUGH. Black tourmaline in quartz, mica, zoisite, ru- tile, actinolite, scapolite, spodumene, roofing slate. BRIDGEWATER. Talc, dolomite, magnetite, steatite, chlorite, gold, native copper, blende, galenite, blue spinel, chalcopyrite. BRISTOL. Rutile, limonite, manganese ores, magnetite. BROOKFIELD. Arsenopyrite, pyrite. CABOT. Garnet, staurolite, hornblende, albite. CASTLETON. Roofing slate, jasper, manganese ores, chlorite. CAVENDISH. Garnet, serpentine, talc, steatite, tourmaline, asbestus, tremolite. CHESTER. Asbestus, feldspar, chlorite, quartz. CHITTENDEN. Psilomelane, pyrolusite, brown iron ore, hematite and magnetite, galenite, iolite. COLCHESTER. Brown iron ore, iron sand, jasper, alum. CORINTH. Chalcopyrite (has been mined), pyrrhotite, pyrite, rutile. COVENTRY. Rhodonite. CRAFTSBURY. Mica in concentric balls, calcite, rutile. DERBY. ^-Mica (adamsite). DUMMERSTON. Rutile, roofing slate. FAIR HAVEN. Roofing slate, pyrite. FLETCHER.- Pyrite, magnetite, acicular tourmaline. GRAFTON. The steatite quarry referred to Graf ton is properly in Athens ; quartz, actinolite. GUILFORD. Scapolite, rutile, roofing slate. HARTFORD. Calcite, pyrite/ cyanite, quartz, tourmaline. IRASBURGH. Rhodonite, psilomelane. JAY. Ghromite, serpentine, amianthus, dolomite. LOWELL. Picrosmine, amianthus, serpentine, talc, chlorite. MARLBORO'. Rhomb spar, steatite, garnet, magnetite, chlorite. MIDDLEBURY. Zircon. MIDDLESEX. Rutile ! (exhausted). MONKTOWN. Pyrolusite, brown iron ore, pipe clay, feldspar. MORETOWN. Smoky quartz! steatite, talc, wad, rutile, serpentine. MORRISTOWN. Galenite. MOUNT HOLLY. Asbestus, chlorite. NEW FANE. Glassy and asbestiform actinolite, steatite, green quarto 338 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. (called chrysoprase at the locality), chalcedony, drusy quartz, garnet, chromic and titanic iron, rhomb spar, serpentine, rutile. NORWICH. Actinolite, feldspar, brown spar> in talc, cyanite, zoisite, chalcopyrite, pyrite. PITTSFORD. Brown iron ore, manganese ores, statuary marble! PLYMOUTH. Siderite, magnetite hematite, gold, galenite. PLYMPTON. Massive hornblende. PUTNEY. Fluorite, limonite, rutile, and zoisite, in boulders,- stau- rolite. READING. Glassy actinolite in talc. READSBORO'. Glassy actinolite, steatite, hematite. RIPTON. Brown iron ore, augite in boulders, octahedral pyrite. ROCHESTER. Rutile, hematite eryst., magnetite in chlorite slate. ROCKINGHAM (Bellows Falls). Cyanite, indicolite, feldspar, tour- maline, fluorite, calcite, prehnite, staurolite. ROXBURY. Dolomite, talc, serpentine, asbestus, quartz. RUTLAND. Magnesite, white marble, hematite, serpentine, pipe clay. SALISBURY. Brown iron ore. SHARON. Quartz crystals, cyanite. SHOREHAM. Pyrite, black marble, calcite. SHREWSBURY. Magnetite and chalcopyrite. STIRLING. Chalcopyrite, talc, serpentine. STOCKBRIDGE. Arsenopy rite, magnetite. STRAFFORD. Magnetite and chalcopyrite (has been worked), native copper, hornblende, copperas. THETFORD. Blende, galenite, cyanite. chrysolite in basalt, pyrrho- tite, feldspar, roojing slate, steatite, garnet. TOWNSHEND. Actinolite, black mica, talc, steatite, feldspar. TROY. Magnetite, talc, serpentine, picrosmine, amianthus, steatite, one mile southeast of village of South Troy, on the farm of Mr. Pierce, east side of Missisco, chromite, zaratite. VERSHIRE. Pyrite, chalcopyrite, tourmaline, arsenopyrite, quartz. WARDSBORO'. Zoisite, tourmaline, tremolite, hematite. WARREN. Actinolite, magnetite, wad, serpentine. WATERBURY. Arsenopyrite, chalcopyrite, rutile, quartz, serpen- tine. WATERVILLE. Steatite, actinolite, talc. WEATHERSFIELD. Steatite, hematite, pyrite, tremolite. WELLS' RIVER. Graphite. WESTFIELD. Steatite, chromite, serpentine. WESTMINSTER. Zoisite in boulders. WINDHAM. Glassy actinolite, steatite, garnet, serpentine. WOODBURY. Massive pyrite. WOODSTOCK. Quartz crystals, garnet, zoisite. MASSACHUSETTS. ALFORD. Galenite, pyrite. ATHOL. Allanite, fibrolite (?), epidote ! babingtonite ? AUBURN. Masonite. JSKTXKE,. Rutile ! mica, pyrite, beryl, feldspar, garnet. GREAT BARRINGTON. Tremolite. BEDFORD. Garnet. CATALOGUE OP AMERICAN LOCALITIES OP MINERALS. 339 BELCHERTON. All anite. BERNARDSTON. Magnetite. BEVERLY. Columbite, green feldspar, cassiterite. BLANFORD. Serpentine, anthophyllite, actinolite ! chromite, cyanite. rose quartz in boulders. BOLTON. Scapolite f petalite, sphene, pyroxene, nuttalite, diopside, boltonite, apatite, magnesite, rhomb spar, allanite, yttrocerite ! spinel. BOXBOROUGH. Scapolite, spinel, garnet, augite, actinolite, apatite. BRIGHTON. Asbestus. BRIMFIELD (road leading to Warren). lolite, adularia, molybdenite, mica, garnet. CARLISLE. Tourmaline, garnet! scapolite, actinolite. CHARLESTOWN. Prehnite, laumontite, stilbite, chabazite, quartz crystals, melanolite. CHELMSFORD. Scapolite (chelmsfordite), chondrodite, Hue spinel, amianthus! rose quartz. CHESTER. Hornblende, scapolite, zoisite, spondumene, indicolite, apatite, magnetite, chromite, stilbite, heulandite, analcite and cha- bazite. At the Emery Mine, Chester Factories. Corundum, marga- rite, diaspore, epidote, corundophilite, chloritoid, tourmaline, menac- canite ! rutile, biotite, indianite ? andesite ? cyanito, amesite. CHESTERFIELD. Blue, green, and red tourmaline, cleavelandite (albite), lepidolite, smoky quartz, microlite, spodumene, cyanite, apatite, rose beryl, garnet, quartz crystals, staurolite, cassiterite, tolumbite, zoisite, uranite, brookite (eumanite), scheelite, anthophyllite, bornite. CON WAY. Pyrolusite, fluorite, zoisite, rutile!! native alum, gale- nite. CUMMINGTON. Rhodonite! cummingtonite (hornblende), marcasite, garnet. DEERFIELD. Chabazite, heulandite, stilbite, amethyst, carnelian, chalcedony, agate. FITCHBURG (Pearl Hill). Beryl, staurolite! garnets, molybdenite. FOXBOROL GH. Pyrite, anthracite. FRANKLIN. Amethyst. GOSHEN. Mica, alfoite, spondumene! blue and green tourmaline, beryl, zoisite, smoky quartz, columbite, tin ore, galenite, beryl (go- shenite), cymatolite. GREENFIELD (in sandstone quarry, half mile east of village). Allo- phane, white and greenish. HATFIELD. Barite, galenite, blende, chalcopyrite. HAWLEY. Micaceous iron, massive pyrite, magnetite, zoisite. HEATH. Pyrite, zoisite. HINSDALE. Brown iron ore, apatite, zoisite. HUBBARDSTON. Massive pyrite. HUNTINGTON (name changed from Norwich). Apatite! Hack tour* maline, beryl, spodumene ! triphylite (altered), blende, quartz crystals, cassiterite. LANCASTER. Cyanite, chiastolite! apatite, staurolite, pinite, and* lusite. LEE. Tremolite! sphene! (east part). LEVERETT. Barite, galenite, blende, chalcopyrite. LEYDEN. Zoisite, rutile. LTTTLEFIELD. Spinel, scapolite, apatite, 340 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. LYNNFIELD. Magnesite on serpentine. M ENDON. Mica ! chlorite. MIDDLEFIELD. Glassy actinolite, rhomb spar, steatite, serpentine, feldspar, drusy quartz, apatite, zoisite, nacrite, chalcedony, talc! deweylite. MILBURY. Vermiculite. NEW BRAINTREE. Black tourmaline. NEWBURY. Serpentine, chrysotile, epidote, massive garnet, side- rite. NEWBURYPORT. Serpentine, nemalite, uranite. Argentiferous ga lenite, tetrahedrite, chalcopyrite, pyrargyrite, etc. NORTHFIELD. Columbite, fibrolite, cyanite. NORWICH. See HUNTINGTON. PALMER (Three Rivers). Feldspar, calcite. PELHAM. Asbestus, serpentine, quartz crystals, beryl, molybdenite, green hornstone, epidote, amethyst, corundum, vermiculite (pelhamite). PLAINFIELD. (Jummingtonite, pyrolusite, rhodonite. RICHMOND. Brown iron ore, gibbsite ! allophane. ROCKPORT. Danalite, cryophyllite, annite, cyrtolite (altered zircon), green and white orthoclase, fergusonite. ROWE. Epidote, talc. SOUTH ROYALSTON. y&ery? / / (now obtained with great difficulty), mica! ! feldspar ! allanite. Four miles beyond old loc., on farm oi Solomon Heywood, mica ! beryl ! feldspar ! menaccanite. RUSSEL. Schiller spar (diallage ?), mica, serpentine, beryl, galenite, chalcopyrite. SALEM. In a boulder, cancrinite, sodalite, elaeolite. SHEFFIELD. Asbestus, pyrite, native alum, pyrolusite, rutile. SHELBURNE. Rutile. SHUTESBURY (east of Locke's Pond). Molybdenite. SOUTHAMPTON. Galenite, cerussite, anglesite, wulfenite, fluorite, barite, pyrite, chalcopyrite, blende, phosgenite, pyromorphite, stolzite, chrysocolla. STERLING. Spodumene, chiastolite, siderite, arsenopyrite, blende, galenite, chalcopyrite, pyrite, sterlingite (damourite). STONEH AM. Nephrite. STURBRIDGE. Graphite, garnet, apatite, bog ore. SWAMPSCOT. Orthite, feldspar. TAUNTON (one mile south). Paracolumbite (titanic iron). TURNER'S FALLS (Conn. River). Chalcopyrite, prehnite, chlorite, siderite, malachite. TYRINGHAM. Pyroxene, scapolite. UXBRIDGE. Galenite. WARWICK. Massive garnet, radiated black tourmaline, magnetite, beryl, epidote. WASHINGTON. Graphite. WESTFIELD. Schiller spar (diallage), serpentine, steatite, cyanite, scapolite, actinolite. WESTFORD. Andalusite ! WEST HAMPTON. Galenite, argentine, pseudomorphous quartz. WEST SPRINGFIELD. Prehnite, ankerite, satin spar, celestite. WEST STOCKBRIDGE. Limonite, fibrous pyrolusite, siderite. WHATELY. Native copper, galenite. CATALOGUE OP AMERICAN LOCALITIES OF MINERALS. 341 WILLIAMSBURG. Zoisite, pseudomorphous quartz, apatite, rose and smoky quartz, galenite, pyrolusite, chalcopyrite. WILLIAMSTOWN. Cryst. quartz. WINDSOR. Zoisite, actinolite, rutile! WORCESTER. Arsenopy rite, idocrase, pyroxene, garnet, amianthus, bucholzite, siderite, galenite. WORTHIN GTON. Cyanite. ZOAR. Bitter spar, talc. RHODE ISLAND. BRISTOL. A methyst. COVENTRY. Mica, tourmaline. CRANSTON. Actinolite in talc, graphite, cyanite, mica, melanterite. CUMBERLAND. Manganese, epidote, actinolite, garnet, titaniferous Iron, magnetite, red hematite, chalcopyrite, bornite, malachite, azu- rite, calcite, apatite, feldspar, zoisite, mica, quartz crystals, ilvaite. DIAMOND HILL. - Quartz crystals, hematite. FOSTER. Cyanite, hematite. GLOUCESTER. Magnetite in chlorite slate, feldspar. JOHNSTON. Talc, brown spar, calcite, garnet, epidote, pyrite, he- matite, magnetite, chalcopyrite, malachite, azurite. NATIC. See WARWICK. NEWPORT. Serpentine, quartz crystals. PORTSMOUTH. Anthracite, graphite, asbestus, pyrite, chalcopyrite. SMITHFIELD. Dolomite, calcite, bitter spar, siderite, nacrite, serpen- tine (bowenite), tremolite, asbestus, quartz, magnetic iron in chlorite slate, talc ! octahedrite, feldspar, beryl. VALLEY FALLS. Graphite, pyrite, hematite. WARWICK (Natic village). Masonite, garnet, graphite. W ESTERLY. Menaccanite. WOONSOCKET. Cyanite. CONNECTICUT BERLIN. Barite, datolite, blende, quartz crystals. BOLTON. Staurolite, chalcopyrite. BRADLEYVILLE (Litchfield). Laumontite. BRISTOL. Chalcocite, chalcopyrite, barite, bornite, dllophane, pyro- orphite, calcite, malachite, galenite, quartz. BROOKFIELD. Galenite, calamine, blende, spodumene, pyrrhotite. CANAAN. Tremolite and white augite ! in dolomite, canaanite (mas- sive pyroxene). CHATHAM. Arsenopyrite, smaltite, cloanthite (chathamite), scoro dite, niccolite, beryl, erythrite. CHESHIRE. Barite! chalcocite, bornite, malachite, kaolin, natrolite, prehnite, chabazite, datolite. CHESTER. Sillimanitef zircon, epidote. CORNWALL. Graphite, pyroxene, actinolite, sphene, scapolite. DANBURY. Danburite, oligoclase, moonstone, brown tourmaline, orthoclase, pyroxene, parathorite. FARMINGTON. Prehnite, chabazite, agate, native copper ; in trap, diabantite. 342 SUPPLEMENT TO DESCRIPTIONS OP SPECIES. GRANBY. Green malachite. GREENWICH. Slack tourmaline. HADDAM. Chrysoberyl! beryl! epidote! tourmaline! feldspar, gar- net! iolite! oligoclase, chlorophyllite ! automolite, magnetite^ adularia, apatite, columbite! (hermannolite), zircon (calyptolitc), mica, pyrite, marcasite, molybdenite,^ allanite, bismuth ochre, bismutite. HADLYME. Chabazite and stilbite in gneiss with epidote and gar- net. HARTFORD. Datolite (Rocky Hill quarry). KENT. Limonite, pyrolusite. LITCHFIELD. Cyanite with corundum, apatite, and andalusite, me- naccanite (washingtonite), chalcopyrite, diaspore, niccoliferous pyrrho- tite, margarodite. LYME. Garnet, sunstone. MIDDLEFIELD FALLS. Datolite, chlorite, etc., in amygdaloid. MIDDLETOWN. Mica, lepidolite with green and red tourmaline, albite, feldspar, columbite ! prehnite, garnet (sometimes octahedral), beryl, topaz, uranite, apatite, pitchblende ; at lead mine, galenite, chal- copyrite, blende, quartz, calcite, fluorite, pyrite sometimes capillary. MILFORD. Sahlite, pyroxene, asbestus, zoisitc, verd-antique, marble, pyrite. NEW BRITAIN. Agate, diabantile, barite, datolite, prehnite, calcite, dolomite. NEW HAVEN. Serpentine, sahlite, stilbite, prehnite, chabazite, laumontite, gmelinite, apophyllite, topazolite. NEWTOWN. Cyanite, diaspore, rutile, damourite, cinnabar. NORWICH. Sillimanite, monazite ! iolite, corundum, feldspar. OXFORD (near Humphreysville). Cyanite, chalcopyrite. PORTLAND. Orthoclase, albite, muacovite, biotite, beryl, tourmaline, columbite, apatite. PLYMOUTH. Galenite, heulandite, fluorite, chlorypliyllite ! garnet. REDDING (near the line of Danbury). Pyroxene, garnet. Near Branchville R. R. depot : Albite, microcline, hebronite, spodumene ! cymatolite, damourite, eosphorite. triploidite, reddingite, dickinsonite, lithiophilite, rhodocltrosite, fairlieldite, apatite, microlite, columuife, garnet, pyrite, tourmaline, staurolite, uranmite, torbernite, autunite, vivianite, triphylite. ROARING BROOK (Cheshire). Datolite f calcite, prehnite, saponite. ROXBURY. Siderite, blende, pyrite ! ! galenite, quartz, chalcopyrite, arsenopyrite, limonite. SALISBURY. Limonite, pyrolusite, triplite, turgite. SAYBROOK. Molybdenite, stilbite, plumbago. SEYMOUR. Native bismuth, arsenopyrite, pyrite. SIMSBURY. Copper glance, green malachite. SOUTHBURY. Rose quartz, laumontite, prehnite, calcite, barite. SOUTHINGTON. Barite, datolite, asteriated quartz crystals. STAFFORD. Massive pyrites, alum, copperas. STONINGTON. Stilbite and chabazite on gneiss. TARIFF VILLE. Datolite. TOLLAND. Staurolite, massive pyrites. TRUMBULL and MONROE. Chlorophane, topaz, beryl, diaspore, pyr- Jrhotite, pyrite, niccolite, scheelite, wolframite (pseudomorph of scheel- ite), rutile, native bismuth, tungstic acid, siderite, arsenopyrite. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 343 argentiferous galenite, blende, scapolite, tourmaline, garnet, albitc, augite, graphic tellurium {?), margarodite. WASHINGTON. Tripolite, menaccanite! (washingtonite of Shepard), rhodochrosite, natrolite. andalusite (New Preston), cyanite. WATERTOWN, near the Naugatuck. White sahlite, monazite. WEST FARMS. Asbestus. WILLIMANTIC. Topaz, monazite, ripidolite. WINCHESTER and WILTON. Asbestus, garnet. NEW YORK. ALBANY CO. BETHLEHEM. Calcite, stalactite, stalagmite, calca- reous sinter, snowy gypsum. COEYMAN'S LANDING. Gypsum, epsoni salt, quartz crystals at Crystal Hill, three miles south of Albany. GUILDERLAND. Petroleum, anthracite, and calcite, on the banks of Norman's Kill, two miles south of Albany. WATER VLIET. Quartz crystals, yellow drusy quartz. ALLEGHANY CO. CUBA. Calcareous tufa, petroleum, 3 miles from the village. CATTARAUGUS CO. FREEDOM. Petroleum. CAYUGA CO. AUBURN. Celestite, calcite, nuor spar, epsomite. SPRINGPORT. At Thompson's plaster beds, sulphur! selenite. SPRING VILLE. Nitrogen springs. UNION SPRINGS. Selenite, gypsum. CHATAUQUE CO. FREDONIA. Petroleum, carburetted hydrogen. LAON A. Petroleum. CLINTON CO. ARNOLD IRON TATSK. Magnetite, epidote, molybde- nite. FINCH ORE BED. Calcite, green and purple fluor. COLUMBIA CO. AUSTERLITZ. - -Earthy manganese, wnlfenite, chalcocite ; Livingston lead mine, galenite. CHATHAM. Quartz, pyrite in cubic crystals in slate (Hillsdale). CANAAN. Chalcocite, chalcopyrite. HUDSON. Epidote, selenite! NEW LEBANON. Nitrogen springs, graphite, anthracite ; at the Ancram lead mine, galenite, barite, blende, wulfenite (rare), chalcopy- rite, calcareous tufa; near the city of Hudson, epsom salt, brown spar, wad. DUTCHESS CO. AMENIA. Dolomite, limonite, turgite. BEEKM AN. Dolomite. DOVER. Dolomite, tremolite, garnet (Foss ore bed), staurolite, limonite. FISHKILL. Dolomite ; near Peck vi lie, talc, asbestus, graphite, horn- Uende, augite, actinolite, hydrous anthophyllite, limonite. NORTH EAST. Chalcocite, chalcopyrite, galenite, blende. RHINEBECK. Calcite, green feldspar, epidote, tourmaline. UNION VALE. At the Clove mine, gibbsite, limonite. ESSEX CO. ALEXANDRIA. Kirby's graphite mine, graphite, py- roxene, scapolite, sphene. CROWN POINT. Apatite (eupyrchroite of Emmons), brown tourma- line ! in the apatite, chlorite, quartz crystals, pink and blue calcite, 344 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. pyrite ; a short distance south of J. C. Hammond's house, garnet, scapolite, chalcopyrite, aventurine feldspar, zircon, magnetic iron (Peru), epidote, mica. KEENE. Scapolite. LE>VIS. labular spar, colophonite, garnet, labradorite, hornblende, actinolite ; ten miles south of the village of Keeseville, arsenopyrite. LONG POND. Apatite, garnet, pyroxene, idocrase, coccolite! I scapo- lite, magnetite, Hue calcite. MclNTYRE. Labradorite, garnet, magnetite. MORIAH, at Sandford Ore Bed. Magnetite, apatite, allanite ! lan- thanite, actinolite, and feldspar ; at Fisher Ore Bed, magnetite, feld- spar, quartz ; at Hail Ore Bed, or " New Ore Bed," magnetite, zircons; on Mill brook, calcite, pyroxene, hornblende, albite ; in the town of Moriah, magnetite, black mica ; Barton Hill Ore Bed, albite. NEWCOMB. Labradorite, feldspar, magnetite, hypersthene. PORT HENRY. Brown tourmaline, mica, rose quartz, serpentine, green and black pyroxene, hornblende, cryst. pyrite, graphite, wollas- tonite, pyrrhotite, adularia ; phlogopite! at Cheever Ore Bed, with magnetite and serpentine. ROGER'S ROCK. Graphite, wollastonite, garnet, collophonite, feld- spar, adularia, pyroxene, sphene, coccolite. SCHROON. Calcite,, pyroxene, chondrodite. TicoNDEROGA. Graphite ! pyroxene, sahlite, sphene, black tour- maline, cacoxene ? (Mt. Defiance). WESTPORT. Labradorite, prehnite, magnetite. WILLSBORO'. Wollastonite, colophonite, garnet, green coccolite, horn- blende. ERIE CO. ELLICOTT'S MILLS. Calcareous tufas. . FRANKLIN CO. CHATEAUGAY. Nitrogen springs, calcareous tufas. M ALONE. Massive pyrite, magnetite. GENESEE CO. Acid springs containing sulphuric acid. GREENE CO. CATSKILL. (Mctte. DIAMOND HILL. Quartz crystals. HAMILTON CO. LONG LAKE. Blue calcite. HERKIMER CO. FAIRFIELD. Quartz crystals, fetid barite. LITTLE FALLS. Quartz crystals I barite, calcite, anthracite, pearl spar, smoky quartz; one mile south of Little Falls, calcite, brown spar, feldspar. MIDDLEVILLE. Quartz crystals ! calcite, brown and pearl spar, an- thracite. NEWPORT. Quartz crystals. SALISBURY. Quartz crystals! blende, galenite, pyrite, chalcopyrite. STARK. Fibrous celestite, gypsum. JEFFERSON CO. ADAMS. Fluor, calc tufa, barite. ALEXANDRIA. On the S. E. bank of Muscolonge Lake, fluorite (exhausted), phlogopite, chalcopyrite, apatite ; on High Island, in the St. Lawrence River, feldspar, tourmaline, hornblende, orthoclase, celestite. ANTWERP. Sterling iron mine, hematite, chalcodite, siderite, mil- lerite, red hematite, crystallized quartz, yellow aragonite, niccoliferous pyrite, quartz crystals, pyrite ; at Oxbow, calcite ! porous coralloidal heavy spar ; near Viooman's lake, calcite ! vesuvianite, phlogopite ! pyroxene, sphene, fluorite, pyrite, chalcopyrite ; also feldspar, bog-iron CATALOGUE OF AMERICAN LOCALITIES OP MINERALS. 345 ore, scapolite (farm of Eggleson), serpentine, tourmaline (yellow, rare). BROWNSVILLE. Celestite in slender crystals, calcite (four miles from Watertown). NATURAL BRIDGE. Oieseckite! steatite pseudomorphous after py- roxene, apatite. NEW CONNECTICUT. Sphene, brown phlogopite. OMAR. Beryl, feldspar, hematite. PHILADELPHIA. Garnets on Indian River, in the village. PAMELIA. Agaric mineral, calc tufa. PIERREPONT. Tourmaline, sphene, scapolite, hornblende. PILLAR POINT. Massive barite (exhausted). THERESA. Fluorite, calcite, hematite, hornblende, quartz crystal, serpentine (associated with hematite), celestite, strontianite. WATERTOWN. Tremolite, agaric mineral, calc tufa, celestite. WILNA. One mile north of Natural Bridge, calcite. LEWIS CO. DIANA (localities mostly near junction of crystalline and sedimentary rocks, and within two miles of Natural Bridge). Scapolite ! wollastonite, green coccolite, feldspar, tremolite, pyroxene ! sphene! ! mica, quartz crystals, drusy quartz, cryst. pyrite, pyrrhotite, blue calcite, serpentine, rensselaerite, zircon, graphite, chlorite, hema- tite, bog-iron ore, iron sand, apatite. GREIG. Magnetite, pyrite. LOWVILLE. Calcite, fluorite, pyrite, galenite, blende, calc tufa. MARTINSBURGH. Wad, galenite, etc., but mine not now opened, calcite. MONROE CO. ROCHESTER. Pearl spar, calcite, snowy gypsum, fluor, celestite, galenite, blende, barite, hornstone. MONTGOMERY CO. PALATINE. Quartz crystals, drusy quartz, anthracite, hornstone, agate, garnet. ROOT. Drusy quartz, blende, barite, stalactite, stalagmite, galenite, pyrite. NEW YORK CO. CORLEAR'S HOOK. Apatite, brown and yellow feldspar, sphene. HARLEM. Epidote, apophyllite, stilbite, tourmaline, vivianite, lamellar feldspar, mica. KINGSBRIDGE. T)'emolite,pyroxene, mica, tourmaline, pyrite, rutile, dolomite. NEW YORK. Serpentine, amianthus, actinolite, pyroxene, hydrous anthophyllite, garnet, staurolite, molybdenite, graphite, chlorite, jasper, necronite, feldspar. In the excavations for the 4th Avenue tunnel, 1875, harmotome, stilbite, chabazite, heulandite, etc. NIAGARA CO. LEWISTON. Epsomite. LOCKPORT. Celestite, calcite, selenite, anhydrite, fluorite, dolomite, blende. NIAGARA FALLS. Calcite, fluorite, blende, dolomite. ONEIDA CO. BOONVILLE. Calcite, wollastonite, coccolite. CLINTON. Blende, lenticular argillaceous iron ore in rocks of the Clinton group, strontianite, celestite, the former covering the latter. ONONDAGA CO. CAMILLUS. Selenite and fibrous gypsum. COLD SPRING. Axinite. MANLIUS. Gypsum and fluor. SYRACUSE. Serpentine, celestite, selenite, barite. SUPPLEMENT TO DESCRIPTIONS OP SPECIES. ORANGE CO. CORNWALL. Zircon, chondrodite, hornblende, spinel, massive feldspar, fibrous epidote, hudsonite, menaccanite, serpentine, coccolite. DEER PARK. Cryst. pyrite, galenite. MONROE. Mica ! sphene ! garnet, colophonite, epidote, chondrodite, aUanite, bucholzite, brown spar, spinel, hornblende, talc, menaccanite, pyrrhotite, pyrite, chromite, graphite, rastolyte. moronolite. At WILKS and O'NEILL Mine in Monroe. Aragonite, magnetite, dimagnetite (pseud.?), jenkinsite, asbestus, serpentine, mica, hortono- lite. At Two PONDS in Monroe. Pyroxene! chondrodite, hornblende, scapolite! zircon, sphene, apatite. At GREENWOOD FURNACE in Monroe. Chondrodite, pyroxene! mica, hornblende, spinel, scapolite, biotite! menaccanite. At FOREST OF DEAN. Pyroxene, spinel, zircon, scapolite, horn- blende. TOWN OP WARWICK, WARWICK VILLAGE. Spinel! zircon, serpen- tine! brown spar, pyroxene! hornblende! pseudomorphous steatite, feldspar! (Rock Hill), menaccanite, clintonite, tourmaline (R. H.), rutile, sphene, molybdenite, arsenopyrite, marcasite, pyrite, yellow iron sinter, quartz, jasper, mica, coccolite. AMITY. Spinel! garnet, scapolite, hornblende, vesuvianite, epidote! clintonite ! magnetite, tourmaline, warwickite, apatite, chondrodite, talc! pyroxene! rutile, menaccanite, zircon, corundum, feldspar, sphene, calcite, serpentine, schiller spar (?), silvery mica. EDENVILLE. Apatite, chondrodite ! hair -brown hornblende ! tremo- lite, spinel, tourmaline, warwickite, pyroxene, sphene, mica, feldspar, arsenopyrite, orpiment, rutile, menaccanite, scorodite, chalcopyrita, leucopyrite (or lollingite), allanite. WEST POINT. Feldspar, mica, scapolite, sphene, hornblende, allanite. PUTNAM CO. BREWSTER, Tilly Foster Iron Mine. Chondrodite! (also humite and clino-humite) crystals very rare, magnetite, dolomite, serpentine, pseudomorphs, brucite, enstatite, ripidolite, biotite, actino- lite, apatite, pyrrhotite, fluorite, albite, epidote, sphene. ANTHONY'S NOSE, at top, pyrite, pyrrhotite, pyroxene, hornblende, magnetite. CARMEL (Brown's quarry). Anthophyllite, schiller spar (?), orpi- ment, arsenopyrite, epidote. COLD SPRING. Chabazite, mica, sphene, epidote. PATTERSON. White pyroxene! calcite, asbestus, tremolite, dolomite, massive pyrite. PHILLIPSTOWN. Tremolite, amianthus, serpentine, sphene, diopside, C'.n coccolite, hornblende, scapolite, stilbite, mica, laumontite, gur- te, calcite, magnetite, chromite. PHILLIPS Ore Bed. Hyalite, actinolite, massive pyrite. RENSSELAER CO. Hoosic. Nitrogen springs. LANSINGBURGH. Epsomite, quartz crystals, pyrite. TROY. Quartz crystals, pyrite, selenite. RICHMOND CO. ROSSVILLE. Lignite, cryst. pyrite. QUARANTINE. Asbestus, amianthus, aragonite, dolomite, gurhofite brucite, serpentine, talc, magnesite. ROCKLAND CO. CALDWELL. Calcite. GRASSY POINT. Serpentine, actinolite. CATALOGUE OP AMERICAN LOCALITIES OF MINERALS. 347 HAVEB STRAW. Hornblende, barite. LADENTOWN. Zircon, malachite, cuprite. PIERMONT. Datolite, stilbite, apophyllite, stellite, prehnite, tliom- sonite, calcite, chabazite. ST. LAWRENCE CO. CANTON. Massive pyrite, calcite, brown tourmaline, sphene, serpentine, talc, rensselaerite , pyroxene, hematite, chalcopyrite. DE KALE. Hornblende, barite, fluorite, trcmolite, tourmaline, blende, graphite, pyroxene, quartz (spongy), serpentine. EDWARDS, Brown and silvery mica ! scapolite, apatite, quartz crys- tals, actinolite, tremolite! hematite, serpentine, magnetite. FINE. Black mica, hornblende. FOWLER. Barite, quartz crystals ! hematite, blende, galenite, tremo- lite, chalcedony, bog ore, satin spar (assoc. with serpentine), pyrite, chalcopyrite, actinolite, rensselaerite (near Somerville). GOUVERNEUR. Calcite ! serpentine! Jwrriblende! scapolite! ortho- clase, tourmaline ! idocrase (one mile south of G.), pyroxene, malaco- lite, apatite, rensselaerite, serpentine, sphene, fluorite, barite (farm of Judge Dodge \ black mica, phlogopite, tremolite! asbestus, hematite, graphite, vesuvianite (near Somerville in serpentine), spinel, houghite, scapolite, phlogopite, dolomite ; three-quarters of a mile west of Som- erville, chondrodite, spinel ; two miles north of Somerville, apatite, pyrite, brown tourmaline / ! HAMMOND. Apatite! zircon! (farm of Mr. Hardy), orthoclase (loxo case\ pargasite, barite. pyrite, purple fluorite, dolomite. HERMON. Quartz crystals, hematite, siderite, pargasite, pyroxene, serpentine, tourmaline, bog-iron ore. MACOMB. Blende, mica, galenite (on land of James Averill), ephene. MINERAL POINT, Morristown. Fluorite, blende, galenite, phlogo- pite (Pope's Mills), barite. OGDENSBURGH. Labradorite . PITCAIRN. Satin spar, associated with serpentine. POTSDAM. Hornblende! ; eight miles from Potsdam, on road to Pierrepont, feldspar, tourmaline, black mica, hornblende. ROSSIE (Iron Mines). Barite, hematite, coralloidal aragonite in mines near Somerville, limonite, quartz (sometimes stalactitic at Parish Iron Mine\ pyrite, pearl spar. ROSSIE Lead Mine. Calcite! galenite! pyrite, celestite, chalcopyrite, hematite, cerussite, anglesite, octahedral fluor, black phlogopite. Elsewhere in ROSSIE. Calcite, barite, quartz crystals, chondrodite (near Yellow Lake), feldspar! pargasite! apatite, pyroxene, horn- blende, sphene, zircon, mica, fluorite, serpentine, automolite, pearl spar, graphite. RUSSEL. Pargasite, specular iron, quartz (dodec.), calcite, serpen- tine, rensselaerite, magnetite. SARATOGA CO. GREENFIELD. Chrysoberyl! garnet! tourma- line ! 'mica, feldspar, apatite, graphite, aragonite (in iron mines). SCHOHARIE CO. BALL'S CAVE, and others. Calcite, stalactites. CARLISLE. Fibrous barite, cryst. and jibrous calcite. MIDDLEBURY. Asphaltic coal, calcite. SHARON. Calcareous tufa. SCHOHARIE. Fibrous celestite, strontianite ! cryst. pyrite! 348 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. SENECA CO. CANOGA. Nitrogen springs. SULLIVAN CO. WURTZBORO'. Galenite, Uende, pyrite, chalco> pyrite. TOMPKINS CO. ITHACA. -Calcareous tufa. ULSTER CO. ELLENVILLE. Galenite, blende, chalcopyrite / quartz, brookite. M ARBLETOWN. Pyrite. WARREN CO. CALDWELL. Massive feldspar. CHESTER. Pyrite, tourmaline, rutile, chalcopyrite. DIAMOND ISLE (Lake George). Calcite, quartz crystals. GLENN'S FALLS. Rhomb spar. JOHNSBUHGH. Fluorite! zircon! graphite, serpentine, pyrite. WASHINGTON CO. FORT ANN. Graphite, serpentine. GRANVILLE. Lamellar pyroxene, massive feldspar, epidote. WAYNE CO. WOLCOTT. Barite. WESTCHESTER CO. ANTHONY'S NOSE. Apatite, pyrite, calcite! in very large tabular crystals, grouped, and sometimes incrusted with drusy quartz. DAVENPORT'S NECK. Serpentine, garnet, sphene. EASTCHESTER. Blende, pyrite, chalcopyrite, dolomite. HASTINGS. Tremolite, white pyroxene. NEW ROCHELLE. Serpentine, brucite, quartz, mica, tremolite, gar- net, magnesite. : PEEKSKILL. Mica, feldspar, hornblende, stilbite, sphene ; three miles south, emery. RYE. Serpentine, chlorite, black tourmaline, tremolite. SING SING. Pyroxene, tremolite, pyrite, beryl, azurite, green mala- chite, cerussite, pyromorphite, anglesite, vauquelinite, galenite, native silver, chalcopyrite. WEST FARMS. Apatite, tremolite, garnet, stilbite, heulandite, cha- bazite, epidote, sphene. YONKEUS. Tremolite, apatite, calcite, analcite, pyrite, tourmaline. YORKTOWN. Fibrolite, monazite, magnetite. WYOMING CO. WYOMING. Rock salt. NEW JERSEY. ANDOVER IRON MINE (Sussex Co.) Will emite, brown garnet. ALLENTOWN (Monmouth Co.) Vivianite, dufrenite. BELLVILLE. Copper mines. . BERGEN. Calcite! datolite! pectolite ! analcite, apophyllite! gme~ Unite, prehnite, sphene, stilbite, natrolite, heulandite, laumontite, cha- bazite, pyrite, pseudomorphous steatite imitative of apophyllite, diabantite. BRUNSWICK. Copper mines : native copper, malachite, mountain leather. BRYAM. Chondrodite, spinel, at Roseville, epidote. CANTWELL'S BRIDGE (Newcastle Co.), three miles west. Vivian- ite. DANVILLE (Jemmy Jump Ridge). Graphite, chondrodite, augite, mica. FLEMINGTON, Copper mines. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 349 FRANKFORT. Serpentine. FRANKLIN and STERLING (Sussex Co.). Spinel ! garnet i rhodonite ! willemite ! franklinite ! zincite ! dysluite ! hornblende, tremolitK, chon- drodite, white scapolitc, black tourmaline, epidote, mi^a, actinohte, augite, sahlite, cocblite. asbestus, jcffcrsontte (augite). calamine, graph- ite, fluorite, beryl, galenite, serpentine, honey-colored sphene, quart/, chalcedony, amethyst, zircon, molybdenite, vivianite, tephroite, rhodo- chrosite, aragonite, sussexite, chalcophanite, rcepperite, calcozincito, vanuxemite, gahnite, hetaerolitc. Also algerite in gran, limestone. FRANKLIN and WARWICK MTS. Pyrite. GREENBROOK. Copper mines. GRIGGSTOWN. Copper mines. HAMBURGH. One mile north, spinel ! tourmaline, phlogopite, horn- blende, limonite, hematite. HOBOKEN. Serpentine (marmolite), brucite, nemalite (or fibrous bru- cite), aragonite, dolomite. HURDSTOWN. Apatite, pyrrhotite, magnetite. IMLAYSTOWN. Vivianite. LOCKWOOD. Graphite, chondrodite, talc, augite, quartz, green spi- nel. MONTVILLE (Morris Co.) Serpentine, chrysotile. MULLICA HILL (Gloucester Co.) Vivianite lining belemnites and other fossils. I NEWTON. Spinel, blue, pink, and white corundum, mica, vesuvian- ite, hornblende, tourmaline, scapolite, rutile, pyrite, talc, calcite, barite, pseudomorphous steatite. PATERSON. Datolite. VERNON. Serpentine, spinel, hydrotalcite. PENNSYLVANIA.* ADAMS CO. GETTYSBURG. Epidote, fibrous and massive. BERKS Co. MORGANTOWN. At Jones's mines, one mile east of Morgantown, malachite, native copper, cJirysocolla, magnetite, allo- phane, pyrite, chalcopyrite, aragonite, apatite, talc, venerite ; two miles N. E. from Jones's mine, graphite, sphene ; at Steele's mine, one mile N. W. from St. Mary's, Chester Co., magnetite, micaceous iron, coccolite, brown garnet. READING. Smoky quartz crystals, zircon, stilbite, iron ore ; near Pricetown, zircon, allanite, epidote ; at Eckhardt's Furnace, allanite with zircon ; at Zion's Church, molybdenite ; near Kutztown, in the Crystal Cave, stalactites ; at Fritz Island, apophyllite, thomsonite, cha- bazite, calcite, azurite, malachite, magnetite, chalcopyrite, stibnite, prochlorite, precious serpentine. BUCKS CO. BUCKINGHAM TOWNSHIP. Crystallized quartz ; near New Hope, vesuvianite, epidote, barite. SOUTHAMPTON. Near the village of Feasterville, in the quarry of George Van Arsdale, graphite, pyroxene, sahlite, coccolite, sphene, green mica, calcite, wollastonite, glassy feldspar sometimes opalescent, phlogopite, blue quartz, garnet, zircon, pyrite, moroxite, scapolite. * See also the Report on the Mineralogy of Pennsylvania, by Dr. F. A. Genth, 1875, 850 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. NEW BRITAIN. Dolomite, galenite, blende, malachite. CARBON CO. SUMMIT HILL, in coal mines. Kaolinite. CHESTER CO. AVONDALE. Asbestus, tremolite, garnet, opal. BIRMINGHAM TOWNSHIP. Amethyst, smoky quartz, serpentine, beryl ; in Ab'm Darlington's lime quarry, calcite. EAST BRADFORD. Near Buffington's bridge, on the Brandy wine, green, blue, and gray cyanite, the gray cyanite found loose in the soil, in crystals ; on the farms of Dr. Elwyn, Mrs. Foulke, Wm. Gib- bons, and Saml. Entrikin, amethyst. At Strode's mill, asbestus, mag- nesite, anthophyllite, epidote, aquacrepitite, oligoclase, drusy quartz, collyrite ? on O.-;borne's Hill, wad, manganesian garnet (massive), sphene schorl ; at Caleb Cope's lime quarry, fetid dolomite, necronite, garnets, blue cyanite, yellow actinolite in talc ; near the Black Horse Inn, indu- rated talc, rutile ; on Amos Davis's farm, orthite! massive, from a grain to lumps of one pound weight ; near the paper-mill on the Brandy- wine, zircon, associated with titaniferous iron in blue quartz. WEST BRADFORD. Near the village of Marshalton, green cyanite, rutile, scapolite, pyrite, staurolite ; at the Chester County Poor-house limestone quarry, chesterlite ! in crystals implanted on dolomite, ru- tile ! in brilliant acicular crystals, which are finely terminated, calcite in scalenohedrons, zoisite, damourite ? in radiated groups of crystals on dolomite, quartz crystals ; on Smith & McMullin's farm, epidote. CHARLESTOWN. Pyromorphite, cerussite, galenite, quartz. COVENTRY. Allanite, near Pughtown. SOUTH COVENTRY. In Chrisman's limestone quarry, near Coventry village, augite, sphene, graphite, zircon in iron ore (about half a mile from the village). EAST FALLOWFIELD. Soapstone. EAST QOSHEN. Serpentine, asbestus, magnetite (lodestone), gar- net. ELK. Menaccanite with muscovite, chromite ; at Lewisville, black tourmaline. WEST QOSHEN. On the Barrens, one mile north of West Chester, amianthus, serpentine, cellular quartz, jasper, chalcedony, drusy quartz, chlorite, marmolite, indurated talc, magnesite in radiated crys- tals on serpentine, hematite, asbestus; near R. Taylor's mill, chromite in octahedral crystals, deweylite, radiated magnesite, aragonite, stauro- lite, garnet, asbestus, epidote ; zoisite on hornblende at West Chester water- works (not accessible at present). NEW GARDEN. At Nivin's limestone quarry, broicn tourmaline, ne- cronite, scapolite, apatite, brown and green mica, rutile, aragonite, fibrolite, kaolinite, tremolite. KENNETT. Actinolite, brown tourmaline, brown mica, epidote, tre- molite, scapolite, aragonite ; on Wm. Cloud's farm, sunstone! ! cha- bazite, sphene. At Pearce's old mill, zoisite, epidote, sunstone ; sun- stone occurs in good specimens at various places in the range of horn- blende rocks running through this township fromN. E. toS. W. LOWER OXFORD. Garnets, pyrite in cubic crystals. LONDON GROVE. Rutile, jasper, chalcedony (botryoidal), large and rough quartz crystals, epidote ; on Wm. Jackson's farm, ydlow and Hack tourmaline, tremolite, rutile, green mica, apatite ; at Pusey's quarry, rutile, tremolite. EAST MARLBOROUGH. On the farm of Bailey & Brother, one mile CATALOGUE OP AMERICAN LOCALITIES OP MINERALS. 351 south of Unionville, bright yellow and nearly white tourmaline, ches- terlite, albite, pyrite ; near Marlborough meeting-house, epidote, ser- pentine, acicular black tourmaline in white quartz ; zircon in small perfect crystals loose in the soil at Pusey's sawmill, two miles S. W. of Unionville. WEST MARLBORO UGH. Near Logan's quarry, staurolite, cyanite, yellow tourmaline, rutile, garnets ; near Doe Run village, hematite, scapolite, tremolite ; in R. Baily's limestone quarry, two and a half miles S. VV. of Unionville, fibrous tremolite, cyanite, scapolite. NEWLIN. On the serpentine barrens, one and a half mile N. E. of Unionville, corundum ! massive and crystallized, also in crystals in albite, often in loose crystals covered with a thin coating of steatite, spinel (black), talc, picrolite, brucite, green tourmaline, with flat pyram- idal terminations in albite, unionite, (rare), enphyllit?, mica in hexagonal crystals, feldspar, beryl! in hexagonal crystals one of which weighs 51 Ibs., pyrite in cubic crystals, chromic iron, drusy quartz, green quartz, actinolite, emerylits, chloritoid, diallage, oliyoclase ; on John- son Patterson's farm, massive corundum, titaniferous iron, clinocMore, emerylite, sometimes colored green by chrome, albite, orthoclase, hal- loysite, margarite, garnets, beryl; on J. Lesley's farm, corundum, crystallized and in massive lumps one of which weighed 5,200 Ibs., diaspore ! ! emerylite! euphyllite, crystallized! green tourmaline, in transparent crystals in the euphyllite, orthoclase ; two miles N. of Unionville, magnetite in octahedral crystals ; one mile E. of Union- ville, hematite; in Edwards's old limestone quarry, purple fluorite, rutile. EAST NOTTINGHAM. Asbestus, chromite in crystals, hallite, beryl. WEST NOTTINGHAM. At Scott's chrome mine, chromite, foliated talc, marmolite, serpentine, chalcedony, rhodochrome ; near Moro Phil- lips's chrome mine, asbestus ; at the magnesia quarry, deweylite, mar- molite, magnesite, leelite, serpentine, chromite ; near Fremont P. O., corundum. WEST PIKELAND. In the iron mines near Chester Springs, gibbsite, zircon, turgite, hematite (stalactitical and in geodes), gothite. PENN. Garnets, agalmatolite. PENNSBURY. On John Craig's farm, brown garnets, mica ; on J. Dil worth's farm, near Fairville, muscovite ! in the village of Fair- ville, sunstone ; near Brinton's Ford, on the Brandywine, chondrodite, yphene, diopside, augite, cocoolite ; at Mendenhall's old limestone quarry, fetid quartz, sunstone ; at Swain's quarry, orthoclase. POCOPSON. On the farms of John Entrikin and Jos. B. Darlington, amethyst. SADSBURY. Rutile ! f splendid geniculated crystals are found loose in the soil for seven miles along the valley, and particularly near the village of Parkesburg, where they sometimes occur weighing on pound, doubly geniculated and of a deep red color ; near Sadsbury village, amethyst, tourmaline, epidote, milk quartz. SCHUYLKILL. In the railroad tunnel at PHCENIXVILLE, dolomite! sometimes coated with pyrite, quartz crystals, yellow blende, brookite, calcite in hexagonal crystals enclosing pyrite; at the WHEATLEY, BROOKDALE, and CHESTER COUNTY LEAD MINES, one and a half mile S. of Phrenixville, pyromorphite ! cerussite ! galenite, anglesite f ! quartz crystals, chalcopyrite, barite, fluorite (white), stolzite, wulfenite } 352 SUPPLEMENT TO DESCRIPTIONS OP SPECIES. calamine, vanadinite, blende ! mimetite / descloizite, gothite, chryso- colla, native copper, malachite, azurite, limonite, calcite, sulphur, py- rite, melaconite, pseudomalachite, gersdorffite, chalcocite ? covellite. THORNBURY. On Jos. H. Brinton's farm, muscovite containing ajcic- ular crystals of tourmaline, rutile, titaniferous iron. TREDYFFRIN. Pyrite in cubic crystals loose in the soil. UWCHLAN. Massive bine quartz, graphite. WARREN. Melanite, feldspar. WEST GOSHEN (one mile from West Chester). Chromite. WILLISTOWN. Magnetite, chromite, actinolite, asbestus. WEST TOWN. On the serpentine rocks, 3 miles' S. of West Ches- ter, dinochlore ! jefferisite ! mica, asbestus, actinolite, magnesite, talc, titaniferous iron, magnetite and massive tourmaline. EAST WHITELAND. Pyrite, in cubic crystals, quartz crystals. WEST WHITELAND. At Gen. Trimble's iron mine (southeast), stal- actitic hematite ! wavellite I ! in radiated stalactites, gibbsite, coeruleo- lactile. WARWICK. At the Elizabeth mine and Keim's old iron mine adjoining, one mile N. of Knauertown, aplome garnet ! in brilliant dodecahedrons, flosferri, pyroxene, micaceous hematite, pyrite in bright octahedral crystals in calcite, chrysocolla, chalcopyrite massive and in single tetrahedral crystals, magnetite, fuscicular hornblende ! bornite, malachite, brown garnet, calcite, byssolite ! serpentine ; near the village of St. Mary's, magnetite in dodecahedral crystals, melanite, garnet ', actinolite in small radiated nodules ; at the Hopewell iron mine, one mile IS. W. of St. Mary's, magnetite in octahedral crystals. COLUMBIA CO. At Webb's mine, yellow blende in calcite ; near Bloomburg, cryst. magnetite. DAUPHIN CO. NEAR HUMMELSTOWN. Green garnets, cryst. amoky quartz, feldspar, micaceous hematite, stilbite, chrysocolla. DELAWARE CO. ASTON TOWNSHIP. Amethyst, corundum, eme- rylite, staurolite, fibrolite, black tourmaline, margarite, sunstone, asbes- tus, anthophyllite, steatite ; near Tyson'o mill, garnet, staurolite ; at Peter's milldam in the creek, pyrope garnet. BIRMINGHAM. Fibrolite, kaolin (abundant), crystals of rutile, ame- thyst ; at Bullock's old quarry, zircon, bucholzite, nacrite, yellow crys- tallized quartz, feldspar. BLUE HILL. Green quartz crystals, spinel. CHESTER. Amethyst, black tourmaline, beryl, crystals of feldspar, garnet, cryst. pyrite, molybdenite, molybdite, chalcopyrite, kaolin, ura- ninite, muscovite, orthoclase, bismutite. CHICHESTER. Near Trainer's milldam, beryl, tourmaline, crystals of feldspar, kaolin ; on Wm. Eyre's farm, tourmaline. CONCORD. Mica, feldspar, kaolin, drusy quartz, meerschaum, stel- lated tremolite, anthophyllite, fibrolite, acicular crystals of rutile, py- rope in quartz, amethyst, actinolite, manganesian garnet, beryl ; in Green's creek, pyrope garnet. DARBY. Blue and gray cyanite, garnet, staurolite, zoisite, quartz, beryl, chlorite, mica, limonite. EDGEMONT. Amethyst, oxide of manganese, crystals of feldspar; one mile east of Edgemont Hall, rutile in quartz. GREEN'S CREEK. Garnet (so-called pyrope). - HAVERFORD. Staurolite with garnet. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 353 MARPLE. Tourmaline, andalusite, amethyst, actinolite, antJiophyl* lite, talc, radiated actinolite in talc, chromite, drusy quartz, beryl, cryst. pyrite, menaccanite in quartz, chlorite. MIDDLETOWN. Amethyst, beryl, black mica, mica with reticulated magnetite between the plates, manganesian garnets! large trapezo hedral crystals, some 3 in. in diameter, indurated talc, hexagonal crystals of rutile, crystals of mica, green quartz ! anthophyllite, radi- ated tourmaline, staurolite, titanic iron, fibrolite, serpentine ; at Len- ni, chlorite, green and bronze vermiculite! green feldspar ; at Mineral Hill, fine crystals of corundum, one of which weighs If lb., actinolite in great variety, bronzite, green feldspar, moonstone, sunstone, graphic granite, magnesite, octahedral crystals of chromite in great quantity, beryl, chalcedony, asbestus, fibrous hornblende, rutile, staurolite, ine- lanosiderite, hallite ; at Painter's Farm, near Dismal Run, zircon with oligoclase, tremolite, tourmaline ; at, the Black Horse, near Media, corundum ; at Hibbard's Farm and at Fairlamb's Hill, chromite in. brilliant octahedrons. NEWTOWN. Serpentine, hematite, enstatite, tremolite. UPPER PROVIDENCE. Anthophyllite, tremolite, radiated asbestus, radiated actinolite, tourmaline, beryl, green feldspar, amethyst (one found on Morgan Hunter's farm weighing over 7 Ibs.), andalusite! (one terminated crystal found on the farm of Jas. Worrell weighs 7 Ibs. ) ; at Blue Hill, very fine crystals of blue quartz in chlorite, amian- thus in serpentine, zircon. LOWER PROVIDENCE. Amethyst, green mica, garnet, large crystals of feldspar ! (some over 100 Ibs. in weight). RADNOR. Garnet, marmolite, deweylite, chromite, asbestus, mag- nesite, talc, blue quartz, picrolite, limonite, magnetite. SPRINGFIELD. Andalusite, tourmaline, beryl, titanic iron, garnet ; on Fell's Laurel Hill, beryl, garnet ; near Beattie's mill, staurolite, apatite ; near Lewis's paper-mill, tourmaline, mica. THORNBURY. Amethyst. HUNTINGDON CO. NEAR FRANKSTOWN. In the bed of a stream and on the side of a hill, fibrous celestite (abundant), quartz crystals. LANCASTER CO. DRUMORE TOWNSHIP. Quartz crystals. FULTON. At Wood's chrome mine, near the village of Texas, bru- citelf zaratite (emerald nickel), pennite! ripidolite! Mmmererite! baltimorite, chromite, williamsite, chrysolite! marmolite, picrolite^ hydromagnesite, dolomite, magnesite, aragonite, calcite, serpentine, hematite, menaccanite, genthite, chrome-garnet, bronzite, millerite ; at Low's mine, hydromagnesite, brucite (lancasterite), picrolite, magne- site, williamsite, chromic iron, talc, zaratite, balumorite, serpentine, hematite ; on M. Boice's farm, one mile N. W. of the village, pyrite in cubes and various modifications, anthophyllite; near Rock Springs, chalcedony, carnelian, moss agate, green tourmaline in talc, titanic iron, chromite, octahedral magnetite in chlorite; at Reynolds's old mine, calcite, talc, picrolite, chromite ; at Carter's chrome mine, brookitc. GAP MINES. Chalcopyrite, pyrrhotite (niccoliferous), millerite in botryoidal radiations, mvianite I (rare), actinolite, siderite, hisingerite, pyrite. PEQUA VALLEY. Eight miles south of Lancaster, argentiferous galenite (said to contain 250 to 300 ounces of silver to the ton?), vau- .quelinite, rutile at Pequea mine ; four miles N. W. of Lancaster,, on 354 SUPPLEMENT TO DESCRIPTIONS OP SPECIES. the Lancaster and Harrisburg Railroad, calamite, galenite, blende; pyrite in cubic crystals is found iu great abundance near the city of Lancaster ; at the Lancaster zinc mines, calamine, blende, tennantite ? smithsonite (pseud, of dolomite), aurichalcite. LEBANON CO. CORNWALL. Magnetite, pyrite (cobaltif erous\ chalcopyrite, native copper, azurite, malachite, chrysocolla, cuprite (hy- drocuprite), allophane, brochantite, serpentine, quartz pseudomorphs ; galenite (with octahedral cleavage), fluorite, covellite, hematite (mica- ceous), opal, asbestus. LEHIGH CO. FRIEDENSVILLE. At the zinc mines, calamine, smithsonite, hydrozincite, massive blende, greenockite, quartz, allo- phane, zinciferous clay, mountain leather, aragonite, sauconite ; near Allentown, magnetite, pipe-iron ore ; near Bethlehem, on S. Mountain, allanite, with zircon and altered sphene in a single isolated mass of syenite, magnetite, martite, black spinel, tourmaline, chalcocite. MIFFLIN CO. Strontianite. MONROE CO. In CHERRY VALLEY. Calcite, chalcedony, quartz; in Poconac Valley, near Judge Mervine's, cryst. quartz. MONTGOMERY CO. CONSHOHOCKEN. Fibrous tourmaline, me- naccanite, aventurine quartz, phyllite ; in the quarry of Geo. Bullock, calcite in hexagonal prisms, aragonite. LOWER PROVIDENCE. At the Perkiomen lead and copper mines, near the village of Shannonville, azurite, blende, galenite, pyromor- phite, cerussite, wulfenite, anglesite, barite, calamine, chalcopyrite, malachite, chrysocolla, brown spar, cuprite, covellite (rare), melaco- nite. libethenite, pseudomalachite. WHITE MARSH. At D. O. Hitner's iron mine, five and a half miles from Spring Mills, limonite in geodes and stalactites, gothite, pyro- lusite, wad, lepidocrocite ; at Edge Hill Street, North Pennsylvania Railroad, titanic iron, braunite, pyrolusite ; one mile S. W. of Hitner's iron mine, limonite, velvety, stalactitic, and fibrous, fibres three inches long, turgite, gothite, pyrolusite, velvet manganese, wad ; near Marble Hall, at Hitner's marble quarry, white marble, granular barite, resem- bling marble ; at Spring Mills, limonite, pyrolusite, gflthite ; at Flat Rock Tunnel, opposite Manayunk, stilbite, lieulandite, chabasite, ilvaite, beryl, feldspar, mica. LAFAYETTE, at the Soapstone quarries. Talc, jefferisite, garnet, albite, serpentine, zoisite, staurolite, chalcopyrite ; at Rose's Serpen- tine quarry, opposite Lafayette, enstatite, serpentine. NORTHAMPTON CO. BUSHKILL TOWNSHIP. Crystal Spring on Blue Mountain, quartz crystals. Near E ASTON. Zircon! (exhausted), nephrite, coccolite, tremolite, pyroxene, sahlite, limonite, magnetite, purple calcite. WILLIAMS TOWNSHIP. Pyrolusite in geodes in limonite beds, go'thite (lepidocrocite) at Glendon. NORTHUMBERLj .AND CO. Opposite SELIN'S GROVE. Cala- mine. PHILADELPHIA CO. FRANKPORD. Titanite in gneiss, apophyl- lite ; on the Philadelphia, Trenton and Connecting Railroad, basanite; at the quarries on Frankford Creek, stilbite, molybdenite, hornblende; on the Connecting Railroad, wad, earthy cobalt ; at Chestnut Hill, magnetite, green mica, chalcopyrite, fluorite. FAIBMOUNT WATER- WORKS. In the quarries opposite Fainnount, CATALOGUE OP AMERICAN LOCALITIES OF MINERALS. 355 autunite ! torbernite, crystals of feldspar, beryl, pseudomorphs after beryl, tourmaline, albite, wad, menaccanite. GORGAS'S and CREASE'S LANE. Tourmaline, cyanite, staurolite, hornstone. Near GERMANTOWN. Black tourmaline, laumontite, apatite; York Road, tourmaline, beryl. HESTONVILLE. Alunogen, iron alum, ortlioclase. HEFT'S MILL. Alunogen, tourmaline, cyanite, titanite. MANAYUNK. At the soapstone quarries above Manayunk, talc, steatite, chlorite, vermiculite, anthophyllite, staurolite, dolomite, apa- tite, asbestus, brown spar, epsomite. MEGARGEE'S Paper-mill. Staurolite, titanic iron, hyalite, apatite, green mica, iron garnets in great abundance. MCKINNEY'S QUARRY, on Rittenhouse Lane. Feldspar, apatite, stil- Ute, natrolite, heulandite, epidote, hornblende, erubescite, malachite. SCHUYLKILL FALLS. Chabazite, titanite, fluorite, epidote, musco- vite, tourmaline, prochlorite. SCHUYLKILL CO. TAMAQUA, near POTTSVILLE, in coal mines. Kaolinite. YORK CO. Bornite, rutile in slender prisms in granular quartz. DELAWARE. NEWCASTLE CO. BRANDYWINE SPRINGS. Bucholzite, fbrolite abundant, sahlite, pyroxene ; Brandywine Hundred, muscovite, en- closing reticulated magnetite. DIXON'S FELDSPAR QUARRIES, six miles N. W. of Wilmington (quarries worked for the manufacture of porcelain). Adularia, albite, oligoclase, beryl, apatite, cinnamon-stone ! ! magnesite, serpentine, as- bestus, black tourmaline ! (rare), indicolite ! (rare), sphene in pyroxene, cyanite. DUPONT'S POWDER MILLS." Hypersthene." EASTBURN'S LIMESTONE QUARRIES, near the Pennsylvania line. Tremolite, Ironzite. QUARRYVILLE. Garnet, spodumene, fibrolite. Near NEWARK, on the railroad. Sphserosiderite on drusy quartz, jasper (ferruginous opal), cryst. spathic iron in the cavities of cellular quartz. WAY'S QUARRY, two miles south of Centreville. Feldspar in fine cleavage masses, apatite, mica, deweylite, granular quartz. WILMINGTON. In Christiana quarries, metattoidal diallage. KENNETT TURNPIKE, near Centreville. Cyanite and garnet. HARTFORD CO. Deweylite. KENT CO. Near MIDDLETOWN, in Wm. Folk's marl pits. Fm- anite ! On CHESAPEAKE AND DELAWARE CANAL. Retinasphalt, pyrite, amber. SUSSEX CO. Near CAPE HENLOPEN. Vivianite. MARYLAND. BALTIMORE (Jones's Falls, If mile from B.). Chabazite (haydenite), heulandite (beaumontite of Levy), pyrite, lenticular carbonate of iron, mica, stilbite. 356 SUPPLEMENT TO DESCRIPTIONS OP SPECIES. Sixteen miles from Baltimore, on the Gunpowder. Graphite. Twenty-three miles from 13., on the Gunpowder. Talc. Twenty-five miles from B., on the Gunpowder. Magnetite, sphene, pycnite. Thirty miles from B., in Montgomery Co., on farm of S. Eliot. Gold in quartz. Eight to twenty miles north of B., in limestone. Tremolite, augite, pyrite, brown and yellow tourmaline. Fifteen miles north of B. Sky-blue chalcedony in granular lime- stone. Eighteen miles north of B., at Scott's mills. Magnetite, cyanite. BAKE HILLS. Chromite, asbestus, tnmolite, talc, hornblende, ser- pentine, chalcedony, meerschaum, baltimorite, chalcopyrite, mag- netite. CAPE SABLE, near Magothy R. Amber, pyrite, alum slate. CARROLL Co. Near Sykesville, Liberty Mines, gold, magnetite, pyrite (octahedrons), chalcopyrite, linnseite (carrollite) ; at Patapsco Mines, near Finksburg, bornite, malachite, siegenite, linnceite, reming- tonite, magnetite, chalcopyrite ; at Mineral Hill mine, bornite, chalco- pyrite, ore of nickel (see above), gold, magnetite. CECIL Co., north part. Chromite in serpentine. COOPTOWN, Harford Co. Olive-colored tourmaline, diallage, talc of green, blue, and rose colors, lirniform asbestus, chromite, serpentine. DEER CREEK. Magnetite! in chlorite slate. FREDERICK Co. Old Liberty mine, near Liberty Town, black cop- per, malachite, chalcocite, specular iron ; at Dollyhyde mine, bornite, chalcopyrite, pyrite, argentiferous galenite in dolomite. MONTGOMERY Co. Oxide of manganese. SOMERSET and WORCESTER Cos., north part. Bog-iron ore, mvi- anite. ST. MARY'S RIVER. Gypsum! in clay. PYLESVILLE, Harford Co. Asbestus mine. VIRGINIA, WEST VIRGINIA, AND DISTRICT OF COLUMBIA. ALBEMABLE Co., a little west of the Green Mts. Steatite, graphite, galenite. AMHERST Co. Along the west base of Buffalo Ridge, copper ores; on N. W. slope of Friar Mtn., allanite, magnetite, zircon, sipylite. AUGUSTA Co. At Weyer's (or Weir's) cave, sixteen miles north- east of Staunton, and eighty -one miles northwest of Richmond, cal- cite, stalactites. BLCKINCHAM Co. Gold at Garnett and Moseley mines, also, pyrite, pyrrhotite, calcite, garnet ; at Eldridge mine (now London and Vir- ginia mines) near by, and the Buckingham mines near Maysville, gold, auriferous pyrite, chalcopyrite, tennantite, barite ; cyanite, tourmaline, actinolite. CHESTERFIELD Co. Near this and Richmond Co., bituminous coal, native coke. CULPEPPER Co., on Rapidan River. Gold, pyrite. FRANKLIN Co. Grayish steatite. FAUQUIER Co., Barnett's mills. Asbestus, gold mines, barite, cat- cite. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 357 FLUVANNA Co. Gold at Stockton's mine ; also tetradymite, at " Tellurium mine." PHENIX COPPER MINES. Chalcopyrite, etc. GEORGETOWN, D. C. Rutile. GOOCHLAND Co. Gold mines (Moss and Busby's). HARPER'S FERRY, on both sides of the Potomac. Thuringite (owen- ite) with quartz. JEFFERSON Co., at Shepherdstown. Fluor. KANAWHA Co. At Kauavvha, petroleum, brine springs, cannel coal. LOUDON Co. Tabular quartz, drase, pyrite, talc, chlorite, soapstone, asbestus, chromite, actinolite, quartz crystals ; micaceous iron, boruite, malachite, epidote, near Leesburg (Potomac mine). LOUISA Co. Walton gold mine, gold, pyrite, chalcopyrite, argen- tiferous galenite, siderite, blende, anglesite ; boulangerite, blende (at Tinder's mine). NELSON Co. Galenite, chalcopyrite, malachite. ORANGE Co. Western part, Blue Ridge, specular iron ; gold at the Orange Grove and Vaucluse gold mines, worked by the " Freehold " and " Liberty " Mining Companies. ROCKBRIDGE Co., three miles southwest of Lexington. Barite, etrengite. SIIENANDOAH Co.. near Woodstock. Fluorite. MT. ALTO, Blue Ridge. Argillaceous iron ore. SPOTTSYLVANIA Co., two miles northeast of Chancellorville. Cy- anite ; gold mines at the junction of the Rappahannock and Rapidan ; on the Rappahanuock (Marshall mine); Whitehall mine, affording also tedradymite. STAFFORD Co., eight or ten miles from Falniouth. Micaceous iron, gold, tedradymite, silver, galenite, vivianite. WASHINGTON Co., eighteen miles from Abingdon. Rock salt with gypsum. WYTHE Co. (Austin's mines). Cerussite, minium, plumbic ochre, blende, calamine, galenite, graphite. On the Potomac, twenty-five miles north of Washington City. Na- tive sulphur in gray compact limestone. NORTH CAROLINA. ASHE Co. Malachite, chalcopyrite. BUNCOMBE Co. (now called Madison Co.) Corundum (from a boul- der), margarite, corundophilite, garnet, chromite, barite, fluoi*ite, ru- tile, iron ores, manganese, zircon ; at Swananoa Gap, cyanite. BURKE Co. Gold, monazite, zircon, beryl, corundum, gar net, sphene, graphite, iron ores, tetradymite, montanite (hydrous bismuth tellurate). CABARRUS Co. Phenix Mine, gold, barite, chalcopyrite, auriferous pyrite, -quartz pseudomorph after barite, tetradymite, montanite ; Pi- oneer mines, gold, limonite, pyrolusite, barnhardite, wolfram, scheelite, cuprotungstite, tungstite, diamond, chrysocolla, chalcocite, molybde- nite, chalcopyrite, pyrite ; White mine, needle ore, chalcopyrite, ba- rite ; Long and Muse's mine, argentiferous galenite, pyrite, chalcopy- rite, limonite ; Boger mine, tetradymite ; Fink mine, valuable copper ores ; Mt. Makins, tetrahedrite, magnetite, talc, blende, pyrite, prous- tite, galenite ; Bangle mine, scheelite. 358 SUPPLEMENT TO DESCRIPTIONS OP SPECIES. CALDWELL Co. Chromite. CHATHAM Co. Mineral coal, pyrite, cliloritoid. CHEROKEE Co. Iron ores, gold, galenite, corundum, rutile, cyanite, dainonite. CLEVELAND Co. White Plains, quartz, crystals, smoky quartz, tour- maline, rutile in quartz. CLAY Co. At the Cullakenee mine and elsewhere, corundum (pink), zoisite, tourmaline, margarite, willcoxite, dudleyite. DAVIDSON Co. King's, now Washington mine, native silver, cerus- site, anglesite, scheelite, pyromorphite, galenite, blende, malachite, black copper, wavellite, garnet, stilbite ; five miles from Washington mine, on Faust's .farm, gold, tetradymite, oxide of bismuth and tellu- rium, montanite, chalcopyrite, limonite, spathic iron, epidote ; near Squire Ward's, gold in crystals, electrum. FRANKLIN Co. At Partiss mine, diamonds. GASTON Co. Iron ores, corundum, margarite ; near Crowder's Moun- tain (in what was formerly Lincoln Co.), lazulite, cyanite, garnet, gra- phite ; also twenty miles northeast, near south end of Clubb's Moun- tain, lazulite, cyanite, talc, rutile, topaz, pyrophyllite ; King's Moun- tain (or Briggs) mine, native tellurium, altaite, tedradymite, monta- nite. GUILFORD Co. McCulloch copper and goldmine, twelve miles from Greensboro', gold, pyrite, chalcopyrite (worked for copper), quartz, sid- erite ; copper ore at the old Fentress mine ; at Deep River, compact pyrophyllite (worked for slate-pencils), HAYWOOD Co. Corundum, margarite, damourite. HENDERSON Co. Zircon, sphene (xanthitane). JACKSON Co. Alunogen ? at Smoky Mountain ; at Webster, serpen- tine, chromite, genthite, chrysolite, talc ; Hoghalt Mountain, pink co- rundum, margarite, tourmaline. LINCOLN Co. Diamond ; at Randleman's, amethyst, rose quartz. MACON Co. Franklin, Culsagee mine, corundum, spinel, diaspore, tourmaline, damourite, prochlorite, cnlsageeite, kerrite, maconite. MCDOWELL Co. Brookite, monazite, corundum in small crystals, red and white, zircons, garnet, beryl, sphene, xenotime, rutile, elastic sandstone, iron ores, pyromelane, tetradymite, montanite. MADISON Co. Twenty miles from Asheville, corundum, margarite, chlorite. MECKLENBURG Co. Near Charlotte (Rhea and Cathay mines) and elsewhere, chalcopyrite, gold; chalcotrichite at McGinn's mine; barn- hardtite near Charlotte ; pyrophyllite in Cotton Stone Mountain, dia- mond ; Flowe mine, scheelite, wolframite ; Todd's Branch, monazite. MITCHELL Co. At the Wiseman mica mine, muscovite samarskite, hatchettolite, euxenite, columbite, rogersite, uraninite, gummite, ura- conite, torbernite, autunite ; at Grassy Creek mine, muscomte, samara- kite. MONTGOMERY Co. Steele's mine, ripidolite, albite. MOORE Co. Carbon ton, compact pyrophyllite. ROWAN Co. Gold Hill mines, thirty-eight miles northeast of Char- lotte, and fourteen from Salisbury, gold, auriferous pyrite ; ten miles from Salisbury, feldspar in crysteils.bismuthmite. RANDOLPH Co. Pyrophyllite. RUTHERFORD Co. Gold, graphite, bismuthic gold, diamond, euclase, CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 359 pseudomorphous quartz? chalcedony, corundum in small crystals, epi- dote, pyrope, brookite, zircon, monazite, rutherfordite, samarskite, quartz crystals, itacolumyte ; on the road to Cooper's Gap, cy anile. STOKES and SURKY Cos. Iron ores, graphite. UNION Co. Lemmond gold mine, eighteen miles from Concord (at Stewart's and Moore's mine), gold, quartz, blende, argentiferous gale- nite (containing 29 '4 oz. of gold and b6'5 oz. of silver to the ton, Genth), pyrite, some chalcopyrite. YANCEY Co. Iron ores, amianthus, cliromite, garnet (spessartite), samarskite, columbite. SOUTH CAROLINA. ABBEVILLE DIST. Oakland Grove, gold (Dora mine), galenite, pyro- morphite, amethyst, garnet. ANDERSON DIST. At Pendleton, actinolite, galenite, kaolin, tourma- line. CHARLESTON. Selenite. CHEOWEE VALLEY. Galenite, tourmaline, gold. CHESTERFIELD DIST. Gold (Brewer's mine), talc, chlorite, pyrophyJ- lite, pyrite, native bismuth, bismuth carbonate, red and yellow ochre, whetstone, enargite. DARLINGTON. Kaolin. EDGEFIELD DIST. Psilomelane, GREENVILLE DIST. Galenite, pyromorphite, kaolin, chalcedony in buhrstone, beryl, plumbago, epidote, tourmaline. KERSHAW DIST. Rutile. LANCASTER DIST. Gold (Hale's mine), talc, chlorite, cyanite, ita- columyte, pyrite ; gold also at Blackmail's mine, Massey's mine, Ezell's mine. LAURENS DIST. Corundum, damourite. NEWBERRY DIST. Leadhillite. PICKENS DIST. Gold, manganese ores kaolin, HIGHLAND DIST. Chiastolite, novaculite. SPARTANBURG DIST. Magnetite, chalcedony, hematite ; at the Cow- pens, limonite, graphite, limestone, copperas ; Morgan mine, leadhil- lite, pyromorphite, cerussite. SUMTER DIST. Agate. UNION DIST. Fairforest gold mines, pyrite, chalcopyrite. YORK DIST. Limestones, whetstones, witherite, barite, tetrady- mite. GEORGIA. BURKE AND SCRIVEN Cos. Hyalite. CHEROKEE Co. At Canton Mine, chalcopyrite, galenite, claustha- lite, plumbogummite, hitchcockite, arsenopyrite, lanthanite, harrisite, cantonite, pyromorphite, automolite, zine, staurolite, cyanite ; at Ball- Ground, spodumene. CLARK Co., near Clarksville. Gold, xenotime, zircon, rutile, cyanite, hematite, garnet, quartz. DADE Co. Halloysite, near Rising Fawn. FANNIN Co. Staurolite ! chalcopyrite. 360 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. HABERSHAM Co. Gold, pyrite, chalcopyrite, galenite, hornblende, garnet, quartz, kaolinite, soapstone, chlorite, rutile, iron ores, tourma- line, staurolite, zircon. HALL Co. Gold, quartz, kaolin, diamond. HANCOCK Co. Agate, chalcedony. HEARD Co. Molubdite, quartz. LEE Co. At the Chewacla Lime Quarry, dolomite, barite, quartz crystals. LINCOLN Co. Lazulite ! ! rutile! ! hematite, cyanite, manaccanite, pyrophyllite, gold, itacolumyte rock. LOWNDES Co. Corundum. LUMPKIN Co. At Field's gold mine, near Dahlonega, gold, tetrady- mite, pyrrhotite, chlorite, menaccanite, allanite, apatite. RABUN Co. Gold, ckalcopyrite. SPAULDING Co. Tetradymite. . WASHINGTON Co., near Saundersville. Wavellite, fire opal. ALABAMA. BENTON Co. Antimonial lead ore (boulangerite ?) BIBB Co., Centreville. Iron ores, marbl , barite, coal, cobalt. CHAMBERS Co. Near La Fayette, steatite, garnets, actinolite, chlo- rite ; east of Oak Bowery, steatite. CHILTON Co Muscovite, graphite, limonite. CLEBURNE Co. At Arbacoochee mine, gold, pyrite, and three miles distant cyanite, garnets ; at Wood's min black copper, azurite, chalco- pyrite, pyrite. CLAY Co. Steatite ; near Delta and Ashland, muscovite. Coos A Co. Tantalite, gold, muscovite. RANDOLPH Co. Gold, pyrite, tourmaline, muscovite ; at Louina, porcelain clay, gar et. TALLADEGA C.. Limonite. TALLAPOOSA Co. at Dudley ville. Corundum, margarite, ripidolite, spinel, tourmaline, actinolite, steatite, asbestus, chrysolite, damourite, corundum altered to tourmaline (crystals of the latter containing a nucleus of the former) and also other pseudomorphs, including, at Dudleyville, dudleyite. TUSKALOOSA Co. Goal, galenite, pyrite, vivianite, limonite, calcite, dolomite, cyanite, steatite, quartz crytals, manganese ores. FLORIDA. NEAR TAMPA BAY. Limestone, sulphur springs, chalcedony, carnelian, agate, silicified shells and corals. KENTUCKY. ANDERSON Co. Galenite, barite. CLINTON Co. Geodes of quartz. CBITTENDEN Co. Galenite, fluorite, calcite. EDMONDSON Co. At Mammoth Cave, gypsum, rosettes ! calcite, sta- lactites, nitre, epsomite. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 361 FAYETTE Co. Six miles N. E. of Lexington, galenite, barite, witherite, blende. LIVINGSTON Co. , near the line of Union Co. Galenite, chalcopyrite, large vein of fluorite. MERCER Co. At McAfee, fluorite, pyrite, calcite, barite, celestite. OWEN Co. Galenite, barite. TENNESSEE. BROWN'S CREEK. Galenite, blende, barite, celestite. CARTER Co., foot of Roan Mt. Sahlite, magnetite. CLAIBORNE Co. Calamine, galenite, sinithsonite, chlorite, steatite, magnetite. COCKE Co., near Bush Creek. Cacoxenite? kraurite, iron sinter, stilpnosiderite, brown hematite. DAVIDSON Co.- Selenite, with granular and snowy gypsum, or ala- baster, crystallized and compact anhydrite, jtuorite in crystals ? calcite in crystals. Near Nashville, blue celestite (crystallized, fibrous, and radiated), with barite in limestone. Haysboro', galenite, blende, with barite as the gangue of the ore. DICKSON Co. Manganite. JEFFERSON Co. Calamine, galenite, fetid barite. KNOX Co. Magnesian limestone, native iron, variegated marbles! MAURY Co. Wavellite in limestone. MORGAN Co. Epsom salt, nitrate of lime. POLK Co., Ducktown mines, southeast corner of State. Melaconite, chalcopyrite, pyrite, native copper, bornite, rutile, zoisite, galenite, har- risite, alisonite, blende, pyroxene, tremolite, sulphates of copper and iron in stalactites, allophane, rahtite, chalcocite (ducktownite), chal- cotrichite, azurite, malachite, pyrrhotite, limonite. ROAN Co., easterly declivity of Cumberland Mts. Wavellite in limestone. SEVIER Co., in caverns. Epsomite, soda alum, nitre, nitrate of calcium, breccia marble. SMITH Co. Fluorite. SMOKY MT., on declivity. Hornblende, garnet, staurolite. WHITE Co. Nitre. OHIO. BAINBRIDGE (Copperas Mt., a few miles east of B.). Calcite, barite, pyrite, copperas, alum. CANFIELD. Gypsum ! DUCK CREEK, Monroe Co. Petroleum. LAKE ERIE. Strontian Island, celestite! Put-in-Bay Island, celestite! sulphur! calcite. LIVERPOOL. Petroleum. MARIETTA. Argillaceous iron ore iron ore abundant also in Scioto and Lawrence Cos. OTTAWA Co. Gypsum. POLAND. Gypsum ! 362 SUPPLEMENT TO DESCRIPTIONS OP SPECIES. MICHIGAN. BREST (Monroe Co.). Calcite, amethystine quartz, apatite, celestite. GRAND RAPIDS. ISelenite, fib. and granular gypsum, calcite, dolomite, anhydrite. LAKE SUPERIOR MINING REGION. The four principal regions are Keweenaw Point, Isle Royale, the Ontonagon, and Portage Lake. The mines of Keweenaw Point are along two ranges of elevation, one known as the Greenstone Range, and the other as the Southern or Bohemian Range (Whitney). The copper occurs in the trap or amyg- daloid, and in the associated conglomerate. Rat-foe copper! native silver! chalcopyrite, horn silver, tetrahedrite, manganese ores, epi- dote, prchnite, laumontite, datolite, heulandite, orthoclase, analcite, cha- bazite, compact datolite, chrysocolla, mcsotype (Copper Falls mine), leonhardite (ib.), analcite (ib.), apophyllite (at Cliff mine), wollastonite (ib.), calcite, quartz (in crystals at Minnesota mine), compact datolite, orthoclase (Superior mine), saponite, melaconite (near Copper Harbor, but exhausted), chrysocolla ; on Chocolate River, galenite and sul- phide of copper ; chalcopyrite and native copper at Presq'lsle ; at Albion mine, domeykite ; at Prince Vein, barite, calcite amethyst ; at Albany and Boston mine, Portage Lake, prehnite, analcite, orthoclase, cuprite ; at Sheldon location, domeykite, whitneyite, algodonite ; Quincy mine, calcite, compact datolite. At the Spur Mountain iron mine (magnetite), chlorite pseudomorph after garnet ; Isle Royale, datolite, prehnite. MARQUETTE. Manganite, galenite ; twelve miles west at Jackson Mt., and other mines, hematite, limonite, gbthite! magnetite, jasper. MONROE. Aragonite, apatite. POINT AUX PEAUX (Monroe Co.) Amethystine quartz, apatite, celes- tite, calcite. SAGINAW BAY. At Alabaster, gypsum. STONY POINT (Monroe Co.) Apatite, amethystine quartz, celestite, calcite. ILLINOIS. GALLATIN Co., on a branch of Grand Pierre Creek, sixteen to thirty miles from Shawneetown, down the Ohio, and from half to eight miles from this river. Violet fiuorite! in carboniferous limestone, barite, galenite, blende, brown iron ore. HANCOCK Co. At Warsaw, quartz geodes containing calcite ! chal- cedony, dolomite, blende ! brown spar, pyrite, aragonite, gypsum, bitu- men. HARDIN Co. Near Rosiclare, calcite, galenite, blende ; five miles back from Elizabethtown, bog iron ; one mile north of the river, be- tween Elizabethtown and Rosiclare, nitre. Jo DAVIESS Co. At Galena, galenite, calcite, pyrite, blende ; at Mars- den's diggings, galenite ! blende, cerussite, marcasite in stalactitic form* pyrite. JOLIET. Marble. QUINCY. Calcite! pyrite. SCALES MOUND. Barite, pyrite. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 363 INDIANA. LIMESTONE CAVERNS ; Corydon Caves, etc. Epsom salt. In most of the southwest counties, pyrite, iron sulphate, and feather alum; on Sugar Creek, pyrite and iron sulphate ; in sandstone of Lloyd- Co., near the Ohio, gypsum ; at the top of the blue limestone forma tion, brown spar, calcite. LAWRENCE Co. Spice Valle, kaolinite (=indianaite). MINNESOTA. NORTH SHORE OF L. SUPERIOR (ranjre of hills running nearly north east and southwest, extending from Fond du Lac Superieure to thf Kamanistiqueia River in Upper Canada). Scolecite, apophyllite. preh- nite, stilbite, laumontite, heulandite, harmotome, thomsonite, fluorite, barite, tourmaline, epidote, hornblende, calcite, quartz crystals, pyrite, magnetite, steatite, blende, black oxide of copper, malachite, native copper, chalcopyrite, amethystine quartz, ferruginous quartz, ehalce- dony, carnelian, agate, drusy quartz, hyalite? fibrous quartz, jasper, prase (in the debris of the lake shore), dogtooth spar, augite, native silver, spodumene? chlorite ; between Pigeon Point and Fond du Lac, near Baptism River, saponite (thalite) in amygdaloid. KETTLE RIVER TRAP RANGE. Epidote, nail-head calcite, amethys- tine quartz, calcite, undetermined zeolites, saponite. STILL WATER. Blende. FALLS OF THE ST. CROIX. Malachite, native copper, epidote, nail- head spar (calcite). RAINY LAKE. Actinolite, tremolite, fibrous hornblende, garnet, py- rite, magnetite, steatite. WISCONSIN. BIG BULL FALLS (near). Bog iron. BLUE MOUNDS. Cerussite. HAZEL GREEN. Calcite. LAC DU FLAMBEAU R. Garnet, cyanite. LEFT-HAND R. (near small tributary). Malachite, chalcocite, native copper, cuprite, malachite, epidote, chlorite? quartz crystals. LINDEN. Oalenite, smithsonite, hydrozindte. MINERAL POINT and vicinity. Copper and lead ores, chrysocolla, azuritef chalcopyrite, malachite, galenite. cerussite, anglesite, blende, py)"ite, barite, calcite, marcasite, smithsonite! (including pseudomorphs after calcite and blende), (so-called " dry-bone "), calamine, bornite, hydrozincite. MONTREAL RIVER PORTAGE. Galenite in gneissoid granite. SAUK Co. Hematite, malachite, chalcopyrite. SHULLSBURG. Galenite ! blende, pyrite ; at Emmet's digging, ga- lenite and pyrite. IOWA. Du BUQUE LEAD MINES, and elsewhere. Galenite f calcite, blende, black oxide of manganese ; at Ewing's and Sherard's diggings, smith' 364 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. sonite, calami ne ; at Des Moines, quartz crystals, selenite ; Makoqueta R., limonite ; near Durango, galenite. CEDAU RIVER, a branch of the Des Moines. Selenite in crystals, in the bituminous shale of the coal measures ; also elsewhere on the Des Moines, gypsum abundant ; argillaceous iron ore, spathic iron ; cop- peras in crystals on the Des Moines, above the mouth of Saap and else- where, pyrite, blende. FORT DODGE. Celestite. MAKOQUETA. Hematite. NEW GALENA. Octahedral galenite, anglesite. MISSOURI. For the distribution of the lead mines see page 147. The number of minerals associated with the lead ore varies greatly in the different lead regions. Mine la Motte. and some old openings in Madison C'o., are peculiar in affording cobalt and nickel ores abundantly. At Granby and other mines the chief zinc ore is calamine, or the silicate of zinc, while in the mines of Central and Southwest Missouri it is compara- tively rare, and smithsonite is the prominent ore as is the case in. Wisconsin ; yet calamine is the most abundant zinc ore in the State. As stated by A. Schmidt, the zinc ore, in each case, is found as a sec- ondary product to sphalerite (blende) ; the cerussite often coats the galenite, or has its forms, indicating thus its source ; the limonite is also secondary, and has come in mainly through the oxidation of py- rite. At the Granby mines, the calamine is called, among the miners, " Black Jack ; " blende, " Resin Jack ; " a white massive smithsonite, " White Jack ;" and the cerussite is the " Dry Bone ; " thus departing from ordinary miners' usage. Gold has been found in the drift sands of Northern Missouri (Broadhead). ADAIR Co. Gothite in calcite. BARTON Co. Pickeringite as an effloresence on sandstone. CHARITON Co. Near Salisbury, gypsum (selenite) in coal beds. COLE Co. At' Old Circle Diggings and elsewhere, barite! galenite, chalcopyrite, malachite, azurite, pyrite, calcit*, calamine, sphalerite. COOPER Co. Collins Mine, malachite with azurite, etc. DADE Co. Smithsonite. FRANKLIN Co. Cove Mines, anglesite, galenite, cerussite, barite. IRON Co. At Pilot Knob and Shepherd Mountain, hematite, mag- netite, limonite, manganese oxide, bog manganese. JASPER Co. (adjoins S. E. Kansas). At Joplin Mines, galena ! spha- lerite, pyrite, cerussite, calamine, dolomite, bitumen. JEFFERSON Co. At Valle's, galenite ! cerussite, anglesite, calamine, smithsonite, sphalerite, hydrozincite, chalcopyrite, malachite, azurite, pyrite, barite, witherite, limonite. At Fruinet mines, 8.^ miles from DeSoto R. R. station, galena, barite ! smithsonite ! pyrite, limnite. MADISON Co. At Mine la Motte, gulenite! cerussite! siegenite (nickel- linnaeite), smaltite, asbolite (earthy black cobalt ore), bog manganese, chalcopyrite, malachite, caledonite, plumbogummite, wolframite. MORGAN Co. At Cordray Diggings, galena, blende, barite. NKWTON Co. (adjoins S. E. Kansas). At Granby Mines, galenite! cerusfiitc, calamine! sphalerite, smithsonite, hydrozincite, green-ockite (on sphalerite), pyromorphite, dolomite, calcite, bitumen, buratite. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. 365 ST. FRANCOIS Co Iron Mountain, hematite, magnetite, limonite. ST. Louis Co Near St. Louis, millerite (in the Subcarboniferous St. Louis limestone, largely a inagnesian limestone) with calcite ! ba- rite, fluorUe. WASHINGTON Co. At Potosi, galenite, cerussile, anglesite, barite ARKANSAS. BATESVILLE. In bed of White R., some miles above Batesville, gold. GREEN Co. Near Gainesville, lignite. HOT SPRINGS Co. At Hot Springs, wavellite, thuringite; Magnet Cove, brookite ! schorlomite, elceolite, magnetite, quartz, green coccolite, garnet, apatite, perofskite (hydrotitanite), rutile, ripidolite, thomsouite (ozarkite), microcline, cegirite, protovermiculite. INDEPENDENCE Co. Lafferay Creek, psilomelane. LAWRENCE Co. Hoppe, Bath, and Koch mines, smithsonite, dolo mit<% galenite ; nitre. MARION Co. Wood's mine, smithsonite, hydrozincite (marionite) galenite ; Poke bayou, braunite? MONTGOMERY Co. Variscite. OUACHITA SPRINGS. Quartz? whetstones. PULASKI Co. Kellogg mine, 10 in. north of Little Rock, tetrahedrite. tennantite, nacrite, galenite, blende, quartz. CALIFORNIA. The principal gold mines of California are in Tulare, Fresno, Mari- posa, Tuolumne, Calaveras, El Dorado, Placer, Nevada, Yuba, Sierra, Butte, Plumas, Shasta, Siskiyou, and Del Norte counties, although gold is found in almost every county of the State. The gold occurs in quartz, associated with sulphides of iron, copper, zinc, and lead ; in Calaveras and Tuolumne counties, at the Mellones, Stanislaus, Golden Rule, and Rawhide mines, associated with tellurides of gold and sil- ver ; it is also largely obtained from placer digrings, and further it is found in beach washings in Del Norte and Klamath counties. The copper mines are principally at or near Copperopolis, in Cala- veras County; near Genesee Valley, in Plumas County; near Low Divide, in Del Norte County ; on the north fork of Smith's River ; at Soledad, in Los Angeles county. The mercury mines are at or near New Almaden and North Al- maden, in Santa Clara County ; at New Idria and San Carlos, Monterey County ; in San Luis Obispo County ; at Pioneer mine, and other locali- ties in Lake County ; in Santa Barbara County. ALAMEDA Co. Diabolo Range, magnesite. ALPINE Co. Morning Star mine, enargite, stephanite, polybasite, barite, quartz, pyrite, tetrahedite, pyrargyrite. AMADOU Co. At Volcano, chalcedony, hyalite; Lone Valley, lonite; Fiddletown, diamond. BUTTE Co. Cherokee Flat, diamond, platinum, iridosmine. CALAVERAS Co. Copperopolis, chalcopyrite, malachite, azurite, ser- pentine, picrolite, native copper ; near Murphy's, jasper, opal ; albite, with gold and pyrite ; Melloues mine, calaverite, petzite. 366 SUPPLEMENT TO DESCRIPTIONS OP SPECIES. CoNTRA-CosTA Co. San Antonio, chalcedony. DEL NORTE Co. Crescent City, agate, camel ian ; Low Divide, dial- copy rite, bornite, malachite ; on the coast, iridosmine, platinum, gold, zircon, diamond. EL DORADO Co. Pilot Hill, chalcopyrite; near Georgetown, hessite, from placer diggings ; Roger's Claim, Hope Valley, grossular garnet, in copper ore ; Coloma, chromite ; Spanish Dry Diggings, gold ; Gran- ite Creek, roscoelite, gold ; Forest Hill, diamond ; Cosumues mine, molybdenite. FKESNO Co. Chowchillas, andalusite ; King's River, bornite. HUMBOLDT Co. Cryptomorphite. INTO Co. Inyo district, galenite, cerussite, anglesite, barite, ataca- mite, calcite, grossular garnet ! Surprise Mine, tetrahedrite ; Kear- sarge mine, silver ores ; Cerro Gordo, wulfenite. KERN Co. Green Monster mine, cuproscheelite. LAKE Co. Borax Lake, borax! sassolite, glauberite; Pioneer mine, cinnabar, native mercury, selenide of mercury ; near the Geysers, sulphur, hyalite ; Redington mine, metacinnabarite ; Lower Lake, chromite. Los ANGELES Co. Near Santa Anna River, anhydrite ; Williams Pass, chalcedony ; Soledad mines, chalcopyrite, garnet, gypsum ; Mountain Meadows, garnet, in copper ore. MARIPOSA Co. Chalcopyrite, itacolumyte ; Centreville, cinnabar ; Pine Tree mine, tetrahedrite ; Burns Creek, limonite ; Geyer Gulch, pyrophyllite ; La Victoria mine, azarite ! near Coulterville, cinnabar, gold. MONO Co. Partzite (stibiconite). MONTEREY Co. Alisal mine, arsenic ; near Paneches, chalcedony ; New Idria mine, cinnabar ; near New Idria, chromite, zaratite, chrome garnet ; near Pacheco's Pass, stibnite. NAPA Co. Chromite. NEVADA Co. Grass Valley, gold! in quartz veins, with pyrite, chalcopyrite, blende, arsenopyrite, galenite, quartz, biotite ; near Truckee Pass, gypsum ; Excelsior Mine, molybdenite, with gold ; Sweet Land, pyrolusite. PLACER Co. Miner's Ravine, epidote ! with quartz, gold. PLUMAS Co. Genesee Valley, chalcopyrite ; Hope mines, bornite, sulphur. SANTA BARBARA Co. San Amedio Canon, stibnite, asphaltum, bitu- men, maltha, petroleum, cinnabar, iodide of mercury ; Santa Clara River, sulphur. SAN BERNARDINO Co. Colorado River, agate, trona ; Temescal Mts. , cassiterite ; Russ District, galenite, cerussite ; Francis mine, cerargyrite ; Slate Range, thenardite, borax, common salt ; San Ber- nardino Mts. , graphites. SANTA CLARA Co. New Almaden, cinnabar, calcite, aragonite. ser- pentine, chrysolite, quartz, aragotite ; North Almaden, chromite ; Mt. Diabolo Range, magnesite, datolite, with vcsuvianite and garnet. SAN DIEGO Co. Carisso Creek, gypsum ; San Isabel, tourmaline orthoclase, garnet. SAN FRANCISCO Co. Red Island, pyrolusite and manganese ores. SAN Luis OBISPO Co. Asphaltum, cinnabar, native mercury, chromite. CATALOGUE OF AMERICAN LOCALITIES OP MINERALS. 367 SHASTA Co. Near Shasta City, hematite, in large masses. SIERRA Co. Forest City, gold, arsenopyrite, tellurides. SISKIYOU Co. Surprise Valley, selenite, in large slabs. SONOMA Co. Actinolite, garnets, chromite, serpentine. TTJLARE Co. Near Visalia, magnesite, asphaltum. TUOLUMNE Co. Tourmaline, tremolite ; Sonora, graphite ; Tori Tent, chromite ; Golden Rule mine, petzite, calaverite, altaite, hessite, magnesite, tetrahcdrite, gold ; Whiskey Hill, gold! TRINITY Co. Cassiterite, a single specimen found. LOWER CALIFORNIA- LA PAZ. Cuproscheelite. LORETTO. Natrolite, siderite, selenite. UTAH. BEAVER Co. Bismuthinite, bismite, bismutite. TINTIC DISTRICT. At the Shoebridge mine, the Dragon mine, and the Mammoth vein, enargite with pyrite. Box ELDER Co. Empire mine, wulfenite! UTAH Co. Ammonia alum. In the Wahsatch and Oquirrh mountains there are extensive mines, especially of ores of lead rich in silver. At the Emma mine occur galenite, cervantite, cerussite, wulfenite, azurite, malachite, calamine, anglesite, linarite, sphalerite, pyrite, argentite, stephanite, etc. At the Lucky Boy mine, Butterfield Canon, orpiment, realgar. One hundred and twenty miles southwest of Salt Lake City, topaz has been found in colorless crystals. At a silver mine, fibrous se piolite. NEVADA. CARSON VALLEY. Chrysolite. CHURCHILL Co. Near Ragtown, gay-lussite, trona, common salt. COMSTOCK LODE. Gold, native silver, argentite, stephanite, polyba, site, pyrargyrite, proustite, tetrahedrite, cerargyrite, pyrite, chalcopy rite, galenite, blende, pyromorphite, allemontite, arsenolite, quartz, calcite, gypsum, cerussite, cuprite, wulfenite, amethyst, kiistelite. ELKO Co. Emma Mine, chrysocolla. ESMERALDA Co. Alum, 12 m. north of Silver Creek ; at Aurora, fluorite, stibnite ; near Mono Lake, native copper and cuprite, obsi- dian ; Thiel Salt Marsh, ulexite, borax, common salt, thenardite ; Columbus district, ulexite, thenardite, sulphur ; Walker Lake, gyp- sum, hematite ; Silver Peak, salt, saltpetre, sulphur, silver ores. HUMBOLDT DISTRICT. Sheba mine, native silver, jamesonite, stib- nite, tetrahedrite, proustite, blende, cerussite, calcite, bournonite, py- rite, galenite, malachite, xanthocone (?), cuprite. LANDER Co. Austin, polybasite, chalcopyrite, azurite. LINCOLN Co. Rock salt, cerargyrite. MAMMOTH DISTRICT. Ortkoclass, turquoise, Mbnerite, scheelite. NYE Co. Anglesite, stetefeldite, azurite, cerussite, silver cerargyrite. 368 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. REESE RIVEK DISTRICT. Native silver, proustite, pyrargyritc, Btephanite, blende, polybasite, rhodochrosite, embolite, tetrahedrite ! cerargyrite, embolite. SAN ANTONIA Belinont mine, stetefeldtite. SIX-MILE CANON. Selenite. ORMSBY Co. W. of Carson, epidote. STOREY Co. Alum, natrolite, scolecite. WHITE PINE Co. Eberhardt mine, cerargyrite ; Paymaster mine freieslebenite. ARIZONA To the south, south of Tucson, near the Mexican boundary, the re- gion about Tubac Arivaca, the Santa Rita and the Patagonia Mts., noted for silver mines, the ore in part argentiferous galenite ; about Tucson, copper ores ; a little to the north, the Heint/elmann mine, Stromeyerite, chalcocite, tetrahedrite, native silver, atacamite ; on and near the Colorado River, in Yuma County, the Castle Dome, Eu- reka and other mines, of gold, silver, and copper, argentiferous gale- nite the prominent silver ore. In the Penal range, gold ; on the San Francisco River, native copper, covellite, chalcopyrite, malachite, azu- rite ; at Bill Williams Fork, malachite, chrysocolla, atacamite, bro- chantite ; Montgomery mine, Harsayampa district, tetradymite. North of the Qila, just west of the boundary of New Mexico, chalco- cite, cuprite, malachite. OREGON AND WASHINGTON. Gold is obtained from beach washings on the southern coast ; quartz mines and placer mines in the Josephine district ; also on the Powder, Burnt, and John Day's rivers, and other places in Eastern Oregon ; platinum, iridosmine, laurite, on the Rogue River, at Port Orford, and Cape Blanco. In Curry Co. , priceite. At Seattle, Washington T. Scheelite, tourmaline ; at Fidalgo, realgar. IDAHO. In the Owyhee, Boise, and Flint districts, gold, also extensive silver mines ; Poor Man's Lode, cerargyrite ! proustite, pyrargyrite ! -native silver, gold, pyromorphite, quartz, malachite, stephanite ; polybasite ; on Jordan Creek, stream tin ; Rising Star mine, stephanite, argentite t pyrargyrite ; Charity mine, Warren's, scheelite, gold. MONTANA. Many mines of gold, etc., west of the Missouri River. HIGHLAND DISTRICT. Tetradymite. SILVER STAR DIST. Psittacinite. In the Yellowstone Park, in Montana and Wyoming Territories. Geyserite, amethyst! chalcedony, quartz crystals, quartz on calcite, etc. CATALOGUE OF AMERICAN LOCALITIES OF MINERALS. % COLORADO. The principal gold mines of Colorado are in Boulder, Gil pin, Clear Creek, and Jefferson Counties, on a line of country a few miles W. of Denver, extending from Long's Peak to Pike's Peak. A large portion of the gold is associated with veins of pyrite and chalcopyrite ; silver and lead mines are at and near Georgetown, Clear Creek County, and to the westward in Summit County, on Snake and Swan rivers. At the GEORGETOWN mines are found : native silver, pyrargyrite, argentite, tetrahedrite, pyromorphite, galenite, sphalerite, azurite, aragonite, barite, fluorite, mica. TRAIL CREEK. Garnet, epidote, hornblende, chlorite ; at the Free- land Lode, tetrahedrite, tennantite, anglesite, caledonite, cerussite, tenorite, siderite, azurite, minium ; at the Champion Lode, tenorite, azurite, chrysocolla, malachite ; at the Gold Belt Lode, vivianite ; at the Kelly Lode, tenorite ; at the Coyote Lode, malachite, cyano- trichite. Near BLACK HAWK. At Willis Gulch, enargite, fluorite, pyrite ; at the Gilpin County Lode, cerargyrite ; on Gregory Hill, feldspar ; North Clear Creek, lievrite. Galenite ! BEAR CREEK. Fluorite, beryl ; near the Malachite Lode, malachite, cuprite, vesuvianite, topazolite ; Liberty Lode, chalcocite. SNAKE RIVER. Penn District, embolite ; at several lodes, pyrar- gyrite, native silver, azurite. RUSSELL DISTRICT. Delaware Lode, cMlcopyrite, crystallized gal- enite. Epidote, pyrite. VIRGINIA CANON. Epidote, fluorite ; at the Crystal Lode, native silver, spinel. SUGAR LOAF DISTRICT. Chalcocite, pyrrhotite, garnet (mangane- sian). CENTRAL CITY. Garnet, tenorite ; at Leavitt Lode, molybdenite ; on Gunnell Hill, magnetite ; at the Pleasantview mine, cerussite. GOLDEN CITY. Aragonite ; on Table Mountain, leucite in amygda- loid. BERGEN'S RANCHE. Garnet, actinolite, calcite. BOULDER Co. Red Cloud Mine : Native tellurium, altaite, hessite (petzite), sylvanite, calaverite, schirmerite. Keystone Mine : Colora- doite, magnolite, ferotellurite, tellurite, roscoelite ? also part of these at Smuggler mine and Mountain Lion mine. Grand View mine : syl- vanite, etc. LAKE CITY, at the Hotchkiss Lode. Petzite, calaverite (?), etc. LAKE Co., Golden Queen mine. Scheelite, gold. PIKE'S PEAK, on Elk Creek. Amazon-stone! ! smoky quartz! aven- turine feldspar, amethyst, albite, fluorite, hematite, anhydrite (rare), columbite. SAN JUAN DISTRICT. Gold, sphalerite, pyrite, galenite, chalcocite, covellite, chalcopyrite. CANADA EAST. ABERCROMBIE. Labrador! te. AUBERT. Gold, iridosmine, platinum. BAIE ST. PA.Tji*.~-Menaccanite f apatite, allanite, rutile. 370 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. BOLTON. Chromite, magnesite, serpentine, picrolite, steatite, bitter spar, wad, rutile. BOUCHEBVILLE. Auyite in trap. BROME. Magnetite, chal copy rite, spJiene, menaccanite, phyllite, sodalite, cancrinite, galenite, chloritoid, rutile. BROUGHTON. Serpentine, steatite. CHAMBLY. Analcite, cliabazite and calcite in trachyte, menaccanite. CHATEAU RICHER. Labrador -ite, hypersthene, andesite. DAILLEBOUT. Blue spinel with clintonite. GRENVILLE. Wollastonite, sphene, muscotite, vesuvianite, calcite, pyroxene, serpentine, steatite (rensselaerite), chondrodite, garnet (cin- namon-stone), zircon, graphite, scapolite. FITZROY. G raphite. HAM. Chromite in serpentine, diallage, antimony! senarmontite ! kermesite, valentinite, stibnite. HUNTERSTOWN. Scapolite, sphene, vesuvianite, garnet, brown tour- maline ! INVERNESS. Bornite, chalcocite, pyrite. LAKE ST. FRANCIS. Andalusite in mica slate. LEEDS. Dolomite, chalcopyrite, gold, chloritoid, chalcocite, bornite, pyrite, steatite. MILLE ISLES. Labradorite! menaccanite, hypersthene, andesite, zircon. MONTREAL. Calcite, augite, sphene in trap, chrysolite, natrolite, dawsonite. MORIN. Sphene, apatite, labradorite. ORFORD. White garnet, chrome garnet, mitterite, serpentine. OTTAWA. Pyroxene. PORTAGE DE FORT. Rensselaerite. POTTON. Chromite, steatite, serpentine, amiantlius. ROUGEMONT. Augite in trap. ST. ARMAND. Micaceous iron ore with quartz, epidote. ST. FRANCOIS BEAUCE. Gold, platinum, iridosmine, menaccaiiite, magnetite, serpentine, chromite, soapstone, barite. ST. JEROME. Sphene, apatite, chondrodite, phlogopite, tourmaline t zircon, garnet, molybdenite, pyrrhotite, wollastonite, labradorite. ST. NORBERT. Amethyst in greenstone. SHERBROOK. At Suffield mine, albite! native silver, argentite, chalcopyrite, blende. SOUTH-CROSBY. Chondrodite. STUKELEY. Serpentine, verd-antique ! schiller spar. SUTTON. Magnetite, in fine crystals, hematite, rutile t dolomite, magnesite, chromiferous talc, bitter spar, steatite. UPTON. Chalcopyrite, malachite, calcite. VAUDREUIL. Limonite, vivianite. YAMASKA. Sphene in trap. CANADA WEST. ARNPRIOR. Calcite. BALSAM LAKE. Molybdenite, scapolite, quartz, pyroxene, pyrite. BATHURST. Barite, black tourmaline, perthite (orthoclase), peristerite (albite), bytoumite, pyroxene, wilsonite, scapolite, apatite, titanite. CATALOGUE OP AMERICAN LOCALITIES OF MINERALS. 371 BRANTFORD. Sulphuric acid spring (4 '2 parts of pure sulphuric acid in 1,000). BROCK VILLE. Pyrite. BROME. Magnetite. BRUCE MINES on Lake Huron. Calcitc, dolomite, quartz, chalcopy rite, chalcocite. BURGESS. Pyroxene, albite, mica, corundum, sphene, chalcopyrite, apatite, black spinel ! spodumene (in a boulder), serpentine, biotite. BYTOWN. Calcite, lytomiite, chondrodite, spinel. CAPE IPPERWASH, Lake Huron. Oxalite in shales. CHAUDIERE VALLEY. Gold, sphalerite, pyrite, pyrrhotite, galenite. CLARENDON. Vesuvianite, tourmaline. DALHOUSIE. Hornblende, dolomite. DRUMMOND. Labradorite. ELIZABETHTOWN. Pyrrhotite, pyrite, calcite, magnetite, talc, phlo- gopite, sidcrite, apatite, cacoxenite. ELMSLEY. Pyroxene, sphene, feldspar, tourmaline, apatite, biotite, zircon, red spinel, chondrodite. FITZROY. Amber, brown tourmaline, in quartz. GOETINEAU RIVER, Blasdell's Mills. Calcite, apatite, tourmaline, hornblende, pyroxene. GRAND CALUMET ISLAND. Apatite plilogopite! pyroxene! horn- blende, sphene, vcsuvianite ! ! serpentine, tremolite, scapolite, brown and black tourmaline! pyrite, loganite. HIGH FALLS OF THE MADAWASKA. Pyroxene ! hornblende. HULL. Magnetite, garnet, graphite. HUNTINGTON. Calcite ! INNISKILLEN. Petroleum. KINGSTON. Celestite. LAC DES CHATS, Island Portage. Brmcn tourmaline! pyrite, cal- cite, quartz. LANARK. Raphilite (hornblende), serpentine, asbestus, perthite (aventurine feldspar), peristerite. LANSDOWNE. Barite ! vein 27 in. wide, and fine crystals, rens. selaerite, sphalerite, wilsonite, labradorite. MADOC. Magnetite. MARMORA. Magnetite, chalcolite, serpentine, garnet, epsomite, specular iron, steatite. McNAB. Hematite, barite. MICHIPICOTON ISLAND, Lake Superior. Domeykite, nicolite, gen- thite, chalcopy rite, native copper, native silver, chalcocite, galenite, amethyst, calcite, stilbite, analcite. At Maimanse Bay: Coracite, chalcocite, clialcopyrite, native copper. N E WBOROUGH. Ghon drodite, graphite. P AKENH AM. Hornblende. PERTH. Apatite in large beds, phlogopite. ST. ADELE. Chondrodite in limestone. ST. IGNACE ISLAND. Calcite, native copper. SILVER ID., Lake Superior. Argentite, native silver, galenite, nic- colite, chalcocite, malachite. SYDENHAM. Celestite. TERRACE COVE, Lake Superior. Molybdenite. WALLACE MINE, Lake Hurpn. Hematite, nickel ore, nickel vitriol, tfiakopyrite. 372 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. NEW BRUNSWICK. ALBEBT Co. Hopewell, gypsum ; Albert mines, coal (albertite) ; Shepody Mountain, alunite in clay, calcite, pyrite, manganite, psilo- melane, pyrolusite. CARLETON Co. Woodstock, chalcopyrite, hematite, limonite, wad. CHARLOTTE Co. Campobello, at Welchpool, blende, chalcopyrite, bornite, galenite. pyrite ; at head of Harbor de Lute, galenite ; Deer Island, on west side, calcite, magnetite, quartz crystals ; Digdighash River on west side of entrance, calcite ! (in conglomerate), chalcedony ; at Rolling Dam, graphite ; Grandmanan, between Northern Head and Dark Harbor, agate, amethyst, apophyllite, calcite, hematite, heulan- dite, jasper, magnetite, natrolite, stilbite ; at Whale Cove, calcite! heulandite, laumontite, stilbite, semi-opal !; Wagaguadavic River, at entrance, azurite, chalcopyrite in veins, malachite. GLOUCESTER Co. Tete-a-Gouche River, eight miles from Bathurst, chalcopyrite (mined), oxide of manganese ! ! formerly mined. KINGS Co. Sussex, near Gloat's mills, on road to Belleisle, argen- tiferous galenite ; one mile north of Baxter's Inn, specular iron in crystals, limonite ; on Capt. McCready's farm, selenite ! ! RESTIGOUCHE Co. Belledune Point, calcite! serpentine, verd-an- tique; Dalhousie, agate, carnelian. ST. JOHN Co. Black River, on coast, calcite, chlorite, chalcopyrite, hematite ! Brandy Brook, epidote, hornblende, quartz crystals ; Carle- ton, near Falls, calcite ; Chance Harbor, calcite in quartz veins, chlo- rite in argillaceous and talcose slate ; Little Dipper Harbor, on west side, in greenstone, amethyst, barite, quartz crystals ; Moosepath, feldspar, hornblende, muscovite, black tourmaline ; Musquash, on east side harbor, copperas, graphite, pyrite ; at Shannon's, chrysolite, serpentine ; east side of Musquash, quartz crystals ! ; Portland at the Falls, graphite ; at Fort Howe Hill, calcite, graphite ; Crow's Nest, asbestus, chrysolite, magnetite, serpentine, steatite ; Lily Lake, white augite ? chrysolite, graphite, serpentine, steatite talc ; How's Road, two miles out, epidote (in syenite), steatite in limestone, tremolite ; Drury's Cove, graphite, pyrite, pyrallolite? indurated talc ; Quaco, at Lighthouse Point, large bed oxide of manganese ; Sheldon's Point, actinolite, asbestus, calcite, epidote, malachite, specular iron ; Cape Spenser, asbestus, calcite, chlorite, specular iron (in crystals) ; West- beach, at east end on Evans's Farm, chlorite, talc, quartz crystals; half a mile west, chlorite, chalcopyrite, magnesite (vein), magnetite ; Point Wolf and Salmon River, asbestus, chlorite, chrysocolla, chalco- pyrite, bornite, pyrite. VICTORIA Co. Tabique River, agate, carnelian, jasper; at mouth, south side, galenite ; at mouth of Wapskanegan, gypsum, salt spring; three miles above, stalactites (abundant) ; Quisabis River, blue phos- phate of iron, in clay. WESTMORELAND Co. Bellevue, pyrite ; Dorchester, on Taylor's Farm, cannel coal ; clay ironstone ; on Ayres's Farm, asphaltum, petro- leum spring ; Grandlance, apatite, selenite (in large crystals) ; Mem- ram cook, coal (albertite) ; Shediac, four miles up Scadoue River, coal. YORK Co. Near Fredericton, stibnite, jamesonite, berthierite ; Pokiock River, stibnite, tin pyrites? in granite (rare). CATALOGUE OP AMERICAN LOCALITIES OP MINERALS. 373 NOVA SCOTIA. ANNAPOLIS Co. Chute's Cove, apophyllite, natrolite ; Gates's Moun- tain, anal cite, magnetite, mesolile ! natrolite, stilbite; Martial's Cove, analcite / chabazite, heulandite ; Moose River, beds of magnetite ; Nictau River, at the Falls, bed of hematite ; Paradise River, black tourmaline, smoky quartz !! ; Port George, faroelite, laumontite, me- solite, stilbite ; east of Port George, on coast, apophyllite containing gyrolite ; Peter's Point, west side of Stonock's Brook, apophyllite ! calcite, heulandite, laumontite ! (abundant), native copper, stilbite ; St. Croix's Cove, chabazite, heulandite. COLCHESTER Co. Five Islands, East River, 'barite! calcite, dolo- mite (ankerite), hematite, chalcopyrite ; Indian Point, malachite, magnetite, red copper, tetrahedrite ; Pinnacle Islands, analcite, calcite, chabazite ! natrolite, siliceous sinter ; Londonderry, on branch of Great Village River, barite, ankerite, hematite, Hmonite, magnetite ; Cook's Brook, ankerite, hematite ; Martin's Brook, hematite, limonite ; at Folly River, below Falls, ankerite, pyrite ; on high land, east of river, ankerite, hematite, limonite ; on Archibald's land, ankerite, barite^ hematite ; Salmon River, south branch of, chalcopyrite, hematite ; Shubenacadie River, anhydrite, calcite, barite, hematite, oxide of manganese ; at the Canal, pyrite ; Stewiacke River, barite (in lime- stone). CUMBERLAND Co. Cape Chiegnecto, barite ; Cape d'Or, analcite, apophyllite!! chabazite, faro'elite, laumontite, mesolite, malachite, natrolite, native copper, obsidian, red copper (rare), vivianite (rare) ; Horse Shoe Cove, east side of Cape d'Or, analcite, calcite, stilbite ; Isle Haute, south side, analcite, apophyllite !! calcite, heulandite !! natrolite, mesolite, stilbite ! ; Joggins, coal, hematite, limonite ; mala- chite and tetrahedrite at Seaman's Brook ; Partridge Island, analcite, apophyllite! (rare\ amethyst! agate, apatite (rare), calcite!! chabazite (acadialite), chalcedony, cat's eye (rare), gypsum, hematite, heulan- dite ! magnetite, stilbite !! ; Swan's Creek, west side, near the Point, calcite, gypsum, heulandite, pyrite ; east side, at Wasson's Bluff and vicinity, analcite!! apophyllite! (rare\ calcite, chabazite!! (acadialite), gypsum, heulandite !! natrolite ! siliceous sinter ; Two Islands, moss agate, analcite, calcite, chabazite, heulandite; McKay's Head, anal- cite, calcite, heulandite, siliceous sinter! DIGBY Co. Briar Island, native copper, in trap ; Digby Neck, Sandy Cove and vicinity, agate, amethyst, calcite, chabazite, hsmatite ! laumontite ( abundant \ magnetite, stilbite, quartz crystals ; Gulliver's Hole, magnetite, stilbite! ; Mink Cove, amethyst, chabazite! quartz crystals; Nichols Mountain, south side, amethyst, magnetite!; Wil- liams Brook, near source, chabazite (green), heulandite, stilbite, quartz crystal. GUYSBORO' Co. Cape Canseau, andalusite. HALIFAX Co. Gay's River, galenite in limestone ; southwest of Halifax, garnet, staurolite, tourmaline ; Tangier, gold! in quartz veins in clay slate, associated with auriferous pyrite, galenite, hema- tite, arsenopyrite, and magnetite ; gold at Country Harbor, Fort Clar- ence, Isaac's Harbor. Indian Harbor, Laidlow's Farm, Lawrencetown, Sherbrooke, Salmon River, Wine Cove, and other places. HANTS Co. Cheverie, oxide of manganese (in limestone) ; Petite 3?4 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. River, gypsum, oxide of manganese ; Windsor, calcite, cryptomorpL (baronatiocalcite), howlite, glauber salt. The last three minerals are found in beds of gypsum. KINGS Co. Black Rock, centrallassite, cerinite ; cyanolite ; a few miles east of Black Rock, prehnite ? stilbite ! ; Cape Blomidon, on the coast between the cape and Cape Split, the following minerals occur in many places (some of the best localities are nearly opposite Cape Sharp) : anakite !! agate, amethyst ! apophyttite ! calcite, chalcedony, chabazite, gmelinite (lederite), hematite, heulandite! laumontite, mag- netite, malachite, mesolite, native copper (rare), natrolite f psilomelane, stilbite! thomsonite, faroelite, quartz; North Mountains, amethyst, bloodstone (rare), ferruginous quartz, mesolite (in soil) ; Long Point, five miles west of Black Rock, heulandite, laumontite!! stilbite!!; Mordeu, apophyttite, mordenite ; Scott's Bay, agate, amethyst, chalce- dony, mesolite, natrolite ; Woodworth's Cove, a f Av miles west of Scott's Bay, agate ! chalcedony ! jasper. LUNENBERG Co. Chester, Gold River, gold in quartz, pyrite, mis- pickel ; Cape la Have, pyrite ; The " Ovens," gold, pyrite, arseno- pyrite ; Petite River, gold in slate. PICTOU Co. Pictou, jet, oxide of manganese, limonite ; at Roder*s Hill, six miles west of Pictou, barite ; on Carribou River, gray copper and malachite in lignite ; at Albion mines, coal, limonite ; East River, limonite. QUEEN'S Co. Westfield. gold in quartz, pyrite, arsenopyrite ; Five Rivers, near Big Fall gold in quartz, pyrite, arsenopyrite, limonite. RICHMOND Co. West of Plaister Cove, barite and calcite in sand- stone ; nearer the Cove, calcite, fluorite (blue), sideiite. SHELBURNE Co. Shelburne near mouth of harbor, garnets (in gneiss) ; near the town, rose quartz ; at Jordan and Sable River, stau- rolite (abundant), schiller spar. SYDNEY Co. Hills east of Lochaber Lake, pyrite, chalcopyrite, side- rite, hematite ; Moiristown, epidote in trap, gypsum. YARMOUTH Co. Cream Pot, above Cranberry Hill, gold in quartz, pyrite ; Cat Rock, Fouchu Point, asbestus, calcite. NEWFOUNDLAND. ANTONY'S ISLAND. Pyrite. CATALINA HARBOR. On the shore, pyrite ! CHALKY HILL. Feldspar. COPPER ISLAND, one of the Wadham group. Chalcopyrite. CONCEPTION BAY. On the shore south of Brigus, bornite and gray copper in trap. BAY OF ISLANDS. Southern shore, pyrite in slate. LAWN. Galenite, cerargyrite, proustite, argentite. PLACENTIA BAY. At La Manche. two miles eastward of Little Southern Harbor, galenite ! ; on the opposite side of the isthmus from Placentia Bay, barite in a large vein, occasionally accompanied by chalcopyrite. SHOAL BAY. South of St. John's, chalcopyrite. TRINITY BAY. Western extremity, barite. HARBOR GREAT ST. LAWRENCE. West side, fluorite, galenite. FOREIGN MINING REGIONS. 375 BRITISH COLUMBIA. CARIBOO DISTRICT. Native gold, galena. ON FRAZER RIVER. Gold, argentiferous tetrahedrite, cerargyrite, cinnabar. OMINICA DISTRICT. Native gold, argentiferous galenite, native silver, silver-amalgam. HOWE'S SOUND. Bornite, molybdenite, mica. TEXADA ID. Magnetite. II. BRIEF NOTICE OF FOREIGN MINING REGIONS. THE geographical positions of the different mining regions are learned with difficulty from the scattered notices in the course of a minera- logical treatise. A general review of the more important is therefore here given, to be used in connection with a good map. A course across Europe, from southeast to northwest, passes over a large part of the mining regions, and it will be found most convenient to the memory to mention them in this order, commencing with the borders of Turkey. 1. The mines of the Bannat in Southern Hungary, near the borders of Turkey (about latitude 45), situated principally at Orawitza, Sasz- ka, Dognaszka, and Moldawa : argentiferous copper ores, chalcocite, malachite, copper pyrites, cuprite, galenite, ores of zinc, cobalt, native gold ; yielding silver, gold, copper, and lead ; rock : syenyte, and gran- ular limestone. 2. The mines of Western Transylvania, about latitude 46, situated between the rivers Maros and Aranyos, at Nagyag, Offenbanya, Sa- lathna, and Vorospatak : native gold, telluric gold, telluric silver, white tellurium, with galenite, blende, orpiment, realgar, stibnite, tet- rahedrite, rhodochrosite or carbonate of manganese, manganblende ; especially valuable in gold and silver. 3. In the mountain range, bounding Transylvania on the north, about latitude 47 40', at Nagybanya, Felsobanya, and Kapnik : na- tive gold, red silver, argentiferous tetrahedrite, chalcopyrite or pyri- tous copper, blende, realgar, stibnite or gray antimony ; rock : por- phyry. 4. In the Konigsberg Mountains, Northern Hungary, about latitude 48 45', at Schemnitz and Kremnitz : argentiferous galenite, and chal- copyrite, native gold, red silver ore, stibnite, some cobalt ores and bis- muth, arsenopyrite or mispickel ; particularly valuable for gold, sil- ver and antimony ; rock : diorite and porphyry. 5. To the east of the Konigsberg Mountains, at Schmolnitz and Retz- banya : chalcopyrite, tetrahedrite, blende, stibnite ; particularly valu- able for copper ; rock : clay slate. 6. Illyria, west of Hungary, at Bleiberg and Raibel (in Carinthia) : argentiferous galenite, calamine, with some chalcopyrite and other ores, affording silver and zinc abundantly ; rock : mountain limestone. Also at Idria, native mercury and cinnabar, in argillaceous schist, 376 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. 7. In Western Styria, at Schladming : arsenical nickel, copper nickel, native arsenic, arsenical iron, largely worked for nickel ; rock : argillaceous slate. Illyria and Styria are noted also for their iron ores, especially siderite or spathic iron. 8. In the Tyrol, at Zell : argentiferous copper and iron ores, aurife- rous pyrite, native gold ; rock : argillaceous slate. 9. In the Erzgebirge separating Bohemia from Saxony, and consist- ing principally of gneiss : A. Bohemian or southern slope, at Joachimsthal, Mies, Schlacken- wald, Zinnwald, Bleistadt, Przibram, Katherinenberg : tin ores, ar- gentiferous galenite (worked principally for silver), arsenical cobalt ores, copper nickel ; affording tin, silver, cobalt, nickel and arsenic. B. Saxon or northern slope, at Altenberg, Geyer, Marienberg, Anna- berg, Schneeberg, Ehrenfriedersdorf, Johanngeorgenstadt, Freiberg : argentiferous galenite (worked only for silver), tin ore, various cobalt and nickel ores, vitreous and pyritous copper ; affording silver, tin, cobalt, nickel, bismuth, and copper. 10. In Silesia, in the'Riesengebirge. an eastern extension of the Erz- gebirge, at Kupferberg, Jauer, Reichenstein : ores of copper, cobalt, affording copper, cobalt, arsenic and sulphur. 11. In Silesia, in the low country east of the Riesengebirge, near the boundary of Poland, at Tarnowitz : calamine, smithsonite, blende, argentiferous galenite ; affording zinc, silver and lead ; rock : moun- tain limestone. 12. Northwest of Saxony, near latitude 51 30', at Eisleben, Gerlstadt. Sangerhausen, and Mansfeld : tetrahedrite, somewhat argentiferous, bornite or variegated copper ore, affording copper ; rock : a marly bi- tuminous schist (kupferschiefer) more recent than the Carboniferous strata. 13. In the Harzgebirge (Hartz Mountains), north of west from Eis- leben, about latitude 51 50', at Clausthal, Zellerfeld, Lauthenthal, Wildemann, Grund, Andreasberg, Goslar, Lauterberg : chalcocite or vitreous copper, tetrahedrite, chalcopyrite, cobalt ores, copper nickel, ruby silver ore, argentiferous galenite. blende, antimony ores ; afford- ing silver, lead, copper, and some gold. 14. In Hesse-Cassel, to the southwest of the Hartz, at Riechelsdorf : arsenical cobalt, arsenical nickel, nickel ochre, native bismuth, bis- muthinite, galenite, affording cobalt ; rock : red sandstone. Also at Bieber, cobalt ores in mica slate. 15. In the Bavarian or Upper Rhine (Palatinate), near latitude 49 45', at Landsberg near Moschel, Wolf stein, and Mprsfeld : cinnabar, native mercury, amalgam, horn quicksilver, pyrite, some tetrahedrite, and chalcopyrite ; rocks : coal formation. 16. Province of the Lower Rhine, at Altenberg, near Aix la Chapelle (or Aachen) : calamine, smithsonite, galenite, affording zinc ; rock : limestone. The same just south in Netherlands, at Limburg, and also to the west at Vedrin, near Namur. 17. There are also copper mines at Saalfeld, west of Saxony, in Saxon-Meiningen, in Southern Westphalia near Siegen, in Nassau at Dillenberg, and elsewhere. 18. In Switzerland, at Canton du Valais : argentiferous galenite, and valuable nickel and cobalt ores. 19. The range of the Vosges parallel with the Rhine, about St. FOREIGN MINING REGIONS. 377 Marie aux-Mines : argentiferous galenite (affording 1-1000 of silver), with pyromorphites, tetrahedrite, antimonial sulphuret of silver, na- tive silver, arsenical cobalt, native arsenic, and pyrite, occasionally auriferous ; affording silver and lead ; rocks : argillaceous schist, sye- nyte, and porphyry. 20. In France there are also the mining districts of the Alps, Au- vergne or the Plateau of Central France, Brittany, and the Pyrenees, but none are very productive, except in iron ores. Brittany resembles Cornwall, and formerly yielded some tin and copper. The valley of Oisans in the Alps, at Allemont, contains argentiferous galenite, arseni- cal cobalt and nickel, gray copper, native mercury, and other ores, in talcose, micaceous and syenytic schists, but they are not now explored. The region of Central France is worked at this time only at Pont- Gibaud, in the department of Puy-de-Dome, and at Vialas and Ville- fort in the Gard. The former is a region of schistose and granite rocks, intersected by porphyry, affording some copper, antimony, lead, and silver ; the latter of gneiss, affording lead and silver, from argen- tiferous galena. The French Pyrenees are worked at the present time only for iron. 21. In England there are two great metalliferous districts : A. On the southwest, in Cornwall, and the adjoining county of De- vonshire : pyritous copper and various other copper ores, tin ores, galenite, with some bismuth, cobalt, nickel and antimony ores ; afford- ing principally copper, tin, and lead ; rocks : granite, gneiss, micaceous and argillaceous schist, elvanyte. B. On the north, in Cumberland, the adjoining parts of Durham, with Yorkshiie and Derbyshire, just south : galenite, and other lead ores, blende, copper ores, calamine and smithsonite (the zinc ores es- pecially at Alstonmoor in Cumberland, and Castleton and Matlock, in Derbyshire), affording some zinc, and three-fifths of the lead of Great Britain, and some copper ; rock: Carboniferous limestone. C. There is also a vein of calamine, blende, and galenite, in the same limestone at Holywell, in Flintshire, on the north of Wales ; another of calamine at Mendip Hills, in Southern England, south of the Bristol Channel, in Somersetshire, occurring in magnesian lime- stone ; mines of copper on the Isle of Anglesey, in North Wales, in Westmoreland and the adjacent parts of Cumberland and Lancashire, in the southwest of Scotland, the Isle of Man, and at Ecton in Stafford- shire, &c. 22. In Spain there are mines A. On the south, in the mountains near the Mediterranean coast, in New Grenada, and east to Carthagena, in Murcia ; also in New Grenada, in the Sierra Nevada, or the mountains of Alpujarras, the Sierra Almagrera, the Sierra de Gador, just back of Almeria, and at Almazarron near Carthagena : galenite, which is argentiferous at the Sierra Almagrera and at Almazarron, affording full 1 per cent, of silver ; rock : limestone, associated with schist and crystalline rocks. B. The vicinity of the range of mountains running westward from Alcaraz (to the district of La Mancha), to Portugal. 1. On the south, near the centre of the province of Jaen, at Linares, latitude 38 5', longitude 3 40': galenite, cerussite, cuprite, malachite, in granite and schists ; affording lead and copper. 2. In La Mancha, at Alcaraz, northeast of Linares, latitude 38 45' : calamine affording abundantly 378 SUPPLEMENT TO DESCRIPTIONS OF SPECIES. zinc. 3. In the west extremity of La Mancha, near latitude 88 38', at Almaden : cinnabar, native mercury, pyrite, in clay slate. 4. South- west of Almaden, in Southern Estremadura, and Northwestern Seville : tetrahedrite ; at Guadalcanal, Cazalla, Rio Tinto : chalcanthite or cop- per vitriol, malachite, with some red silver ore, and native silver, in schists or limestones. There are also mines of lead and copper at Falsete in Catalonia ; in Galicia, a little tin ore ; in the Asturias at Cabrales, copper ores. 23. In Sweden : - 1. At Fahlun, in Dalecarlia : chalcopyrite, bornite ; rock, syenyte and schists. At Finbo and Broddbo : tantalum ores, tin ore. At Sala : argentiferous galeuite, affording lead and silver ; rock, crystalline limestone. At Vena (or Wehna) and at Tunaberg : arseni- cal cobalt, erythrite ; rock, mica slate and gneiss. At Dannemora and elsewhere : magnetic iron ore or magnetite. 24. In Norway, at Kongsberg : argentite or vitreous silver, native silver, horn silver, native gold, galenite, native arsenic, blende ; rock, mica slate. At Modum and Skutterud : cobalt ores, native silver ; rock, mica slate. At Arendal, magnetic iron ore. 25. In Russia: In the Urals (mostly on the Asiatic side), at Ekatherinenberg, Beresof, Nischne Tagilsk, etc. : native gold, plati- num, iridium, native copper, cuprite, malachite. 2. The Altai (Southern Siberia), at Kolyvan and Zmeof : native gold, native silver, argentiferous galena, cerussite, native copper, oxides of copper, mala- chite, chalcopyrite; rocks, metamorphic ^eds and porphyry. 3. In the Daouria Mountains, east of Lake Baikal, at Nertchinsk : argentifer- ous galenite, cerussite, mimetite, gray antimony, arsenopyrite, cala- mine, cinnabar ; rocks, compact limestone and schists. 26. In Australia : In Southern Queensland, and the northern part of New South Wales, or the New England district : tin ore or cassi- terite abundant, with also native gold. In New South Wales, along the Blue Mountains and the continuation of the range parallel with the coast north and south, in the Bathurst, Mudgee, Lachlan and other districts : native gold, chalcopyrite, some cinnabar. In Victoria : na- tive gold. In South Australia, especially at the Burra, Wallaroo, and Moonta mines : copper ores. Other foreign mining regions are the copper mines of Cuba, and South America ; the silver mines of Chili, Bolivia, Peru in South America, and of Mexico ; the gold mines of South America, especially those of Brazil, South Africa, and of the Philippines, Borneo, New Guinea, New Caledonia, and New Zealand in Australasia ; the quick- silver mines of Huanca Velica, Peru, and those of China ; the tin mines of Malacca (principally on the island of Junk-Ceylon), and of the island of Banco between Borneo and Sumatra ; of zinc, in China ; of platinum, in Brazil, Colombia, St. Domingo, and Borneo ; of palla- dium, in Brazil ; of arsenic in Khoordistan, Turkey in Asia, and also in China ; of nickel, in New Caledonia. DETERMINATION OP MINERALS. 379 IV. DETERMINATION OF MINERALS. Itf the determination of minerals, no one order in the succession in which characters should be examined answers for all minerals, or even for all of the same section of species. A. For species having a metallic lustre : Color will be first noted ; and then streak that is, the color of the mineral on a surface scratched or abraded by a fine file, or when very finely powdered, and the lustre of the powder or abraded surface, whether metallic like the min- eral or unmetallic. Hardness should be ascertained when obtaining the streak. Bloivpipe and chemical characters are of the highest value, giving generally the most certain results. Specific gravity is especially distinctive with species hav- ing a metallic lustre, since the differences in density among such species are usually large.* Crystalline form and cleavage are of first importance, whenever the specimen allows of their determination. B. For species without metallic lustre : Streak is sometimes of importance, especially among spe- cies in which it is highly colored. Color is generally of little value owing to the variations that frequently come in through impurities. Lustre is one of the first characters the eye will observe, but its variation under most species is wide, and often it is of little value. State of aggregation and fracture for the most part serve to distinguish only varieties. Hardness is^lso often a varying character, the range under some species being from 1 to 6 in the scale of hard- ness ; and still its indications are generally important. Crystalline form and cleavage are always important when observable. * In using the spiral balance of Jolly (page 65), the spiral spring is put at any de- sired height by means of the sliding rod C. The stand B is raised so that the lower pan, rf, shall be in the water, while the other, c, is above it. The position of the in- dex, or signal, m, is then noted, by sighting across it and observing that the index and the image of it in the mirror are m the same horizontal line ; let *> stand for it. Next put the fragment of the mineral in c, and drop the si and B until the lower pan hange free in the water, and note the position of 7/1, which we may represent by t ; t-s will equal the weight in the air. Now place the fragment in the lower pan. and after adjusting again the stand B, the position of m is noted as before ; call it u. Then tu = loss of weight in water. From these values the specific gravity is at one* obtained. 380 DETERMINATION OP MINERALS. Taste is of limited value, as few minerals are sufficiently soluble ; but among soluble minerals it is easily observed, and often decisive. Action of acids, cold or hot, in trials as to effervescence, solubility, gelatinizing or not, and in making solutions for examination with other reagents, is a very important means of distinguishing species. Blowpipe reactions are easily obtained, and of the high- est value. Specific gravity is an important reliance. Refraction and polarization afford valuable criteria for distinguishing species, and in a few cases no other means are so reliable short of chemical analysis. The following hints may be of service to the beginner in the science, by enabling him to overcome a difficulty in the outset, arising from the various forms and appearance of the minerals quartz and limestone. Quartz occurs of nearly every color, and of various degrees of glassy lustre to a dull stone without the slightest glistening. The common gray- ish cobble-stones of the fields are usually quartz, and others are dull red and brown ; from these there are gradual transi- tions to the pellucid quartz crystal that looks like the best of glass. Sandstones and freestones are often wholly quartz, and the seashore sands are mostly of the same material. It is therefore probable that this "mineral will be often en- countered in mineralogical rambles. Let the first trial ot specimens obtained be made with a file, or the point of a knife, or some other means of trying the hardness ; if the file makes no impression, there is reason to suspect the mineral to be quartz ; and if on breaking it, no regular structure or cleavage plane is observed, but it breaks in all directions with a similar surface and a more or less vitreous lustre, the probability is much strengthened that this con- clusion is correct. The blowpipe may next be used ; and if there is no fusion produced by it in a careful trial there can be little doubt that the specimen is in fact quartz. Calcite (calcium carbonate), including limestone, is an- other very common species. If the mineral collected is rather easily impressible with a file, it may be of this spe- cies ; if it effervesces freely when placed in a test-tube con- taining dilute hydrochloric acid, and is finally dissolved, the probability of its being carbonate of lime is increased ; if DETERMINATION OF MINERALS. 381 the blowpipe produces no trace of fusion, but a brilliant light from the fragment before it, but little doubt remains on this point. Crystalline fragments of calcite break with three equal oblique cleavages. Familiarized with these two Protean minerals by the trials here alluded to, the student has already surmounted the principal difficulties in the way of future progress. Frequently the young beginner, who has devoted some time to collecting all the different colored stones in his neighborhood, on presenting them for names to some prac- tised mineralogist, is a little disappointed to learn that, with two or three exceptions, his large variety includes nothing but limestone and quartz. He is perhaps gratified, however, at being told that he may call this specimen yel- low jasper, that red jasper, another flint, and another horn- stone, others chert, granular quartz, ferruginous quartz, chalcedony, prase, smoky quartz, greasy quartz, milky quartz, agate, plasma, hyaline quartz, quartz crystal, basa- nite, radiated quartz, tabular quartz, etc., etc.; and it is often the case, in this state of his knowledge, that he is best pleased with some treatise on the science in which all these various stones are treated with as much promi- nence as if actually distinct species ; being loth to receive the unwelcome truth, that his whole extensive cabinet con- tains only one mineral. But the mineralogical student has already made good progress when this truth is freely ad- mitted, and quartz and limestone, in all their varieties, have become known to him. The student should be familiar with the use of the blow- pipe and the reactions, as explained on pages 82 and 85 ; and it would be still better if a fuller treatise on the subject had been carefully studied. He should be supplied with the three acids in glass-stoppered bottles ; a fourth bottle con- taining hydrochloric acid diluted one-half with water, for obtaining effervescence with carbonates ; test tubes ; and also the ordinary blowpipe apparatus and tests, including platinum wire, platinum forceps, glass tube, " cobalt solu- tion," litmus and turmeric paper, etc. Also the following : A small file, three-cornered or flat, for testing hardness. A knife with a pointed blade of good steel, for trying hardness. It may be magnetized, to be used as a magnet, though a good horseshoe magnet of small size is better. 382 DETERMINATION OF MINERALS. The series of crystallized minerals, constituting the seals of hardness (see page 63). Diamond and talc are least es- sential. Cutting pliers, for removing chips of a mineral for blow- pipe or chemical assay. A pocket- lens. A hammer weighing about two pounds, resembling a stone-cutter's hammer, having a flat face, and at the opposite end an edge having the same direction as the handle. The handle should be made of the best hickory, and the mortise to receive it should be as large as the handle. A foot scale should be marked on the handle of the hammer, divided into inches, the smallest divisions needed. It will be often of use in getting out a yard-stick, or a ten-foot pole, for large measurements. A similar hammer, having the upper part prolonged to a blunt point, to be used like a pick, is often convenient. A hammer of half a pound weight, like the figure, to be used in trimming specimens. A small jeweler's hammer, for trying the malleability of globules obtained by the blowpipe, and for other purposes, and a small piece of steel for an anvil. Two steel chisels, one six inches long, and the other three. When it is desired to pry open seams in rocks with the larger chisel, two pieces of steel plate should be provided to place on opposite sides of the chisel, after an opening is ob- tained ; this protects the chisel and diminishes friction while driving it. For blasting, if this is desired : Three hand-drills 18, 24, and 36 inches long, an inch in diameter. The best form is a square bar of steel, with a diagonal edge at one end. The three are designed to follow one another. A sledge-hammer of six or eight pounds weight, to use in driving the drill. A sledge-hammer of ten or twelve pounds weight, for breaking up the blasted rock. A round iron spoon, at the end of a wire fifteen or eigh- teen inches long, for removing the pulverized rock from the drill-hole. DETERMINATION OP MINERALS. 383 A crowbar, a pickaxe, and a hoe, for removing stones and earth before or after blasting. Cartridges of blasting powder, to use in wet holes. They should one-third fill the drill-hole. After the charge is put in, the hole should be filled with sand and gravel alone with- out ramming. If any ramming material is used, plaster of Paris is the best, which has been wet and afterwards scraped to a powder. Patent fuse for slow match, to be inserted in the car- tridge, and to lead out of the drill-hole. The table beyond is prepared especially to aid in instruc- tion, and comprises, with few exceptions, only the species that are described in large type through the work, exclusive of the hydrocarbon compounds. The following abbrevia- tions are used in it, in addition to those explained on page 90. With reference to colors : bnh, brownish ; bkh, black- ish ; gnh, greenish ; gyh, grayish ; rdh, reddish. The acids : nit., nitric acid ; sulph. acid, sulphuric acid ; HCL, hydro- cloric acid ; sulph., sulphurous or sulphurous acid. Keactions : gelatinizing with acid, see page 81 ; reaction for sulphur with soda, see page 89 ; blue or red color with cobalt solution, see page 88 ; hydrous, yielding water in a closed tube ; anhydrous, not yielding water in a closed tube, or only traces, see page 86 ; B.B. lithium-red color, see page 87 ; B.B. yreen flame due to boron, see page 87 ; coal is used for charcoal ; fus. for fusible ; in/us, for infusible ; sol. for soluble ; st. for streak. In using the blowpipe it is important to remember that a trial of fusibility with the forceps, if not at once pro- ducing fusion, should be made on a piece of the mineral not larger than the fourth of an ordinary pin-head, andit'should be either oblong and slender, or thin, and be made to pro- ject considerably beyond the points of the forceps, lest the forceps carry off the heat, and cause a failure where there ought to be success. Further, it should be in mind, that in using charcoal, a white coating is always a conse- quence of burning it, since the ash from its own combustion is white. Again, before testing for sulphur by means of soda and a polished surface of silver, it is necessary to try the flame and the soda for sulphur. Gas-flame always con- tains traces of sulphur, and sometimes too much for safe conclusions in this trial. 384 DETERMINATION OF MINERALS. A mineralogist sometimes has occasion to measure dis- tances, and by the following method he may make himself quite an accurate odometer : Let him first find, or make, along a roadside, a measured distance of 800 to 1,000 feet, and then walk it at his ordi- nary walking pace three or four times, and note the number of steps. He will thus ascertain the actual length of his pace, and also find that in his ordinary walk it does not diifer much from thirty inches ; it may be an inch or two less, or one, two, or three more than this. Now four times thirty inches is ten feet. If then, as he walks, he counts one for every fourth step, each unit in the count will stand for ten feet nearly, and 100, for 1,000 feet nearly. If his pace is thirty-one inches, let him add a unit for every thirty in the counting, or, which is the same thing, call his thirty thirty-one, and the needed correction will be made; or if his step is twenty-nine and one-half inches, subtract one from every sixty in the counting, or in other words du- plicate the sixty. Or the correction may be made at the end of the pacing ; if at 600, this number, after adding a thirtieth, becomes 620 ; and the distance would hence be 6,200 feet. With a little practice the counting may be carried on almost unconsciously, and when the thoughts are elsewhere ; that is, unless there is a talking friend by one's side. An instrument, called a pedometer ', of the shape and size of a small watch, is to be had of instrument makers, which, if carried in the waistcoat pocket, will do the registering for the pedestrian and note the distance, without any attention on his part. But the odometer explained above, when once in working order, is always at hand. SYNOPSIS OF THE ARRANGEMENT. I. ELEMENTS. 1. Lustre metallic ; liquid. 2. Lustre metallic ; malleable and eminently sectile. 3. Lustre metallic ; brittle ; B.B. on coal, wholly volatile, with no sulphurous fumes. 4. Lustre metallic ; brittle ; H.=l-2 ; leaves a trace on paper ; B.B. on coal, infusible, no fames or odor. 5. Unmetallic ; burns readily with a blue flame. 6. Lustre adamantine ; H. = 10. DETERMINATION OF MINERALS. 385 II. MINERALS NOT ELEMENTS, THAT B.B. ON COAL ARE WHOLLY VOLATILE. 1. Lustre metallic ; streak metallic. 2. Lustre unmetallic ; streak same as color. III. COMPOUNDS, OF GOLD, SILVER, COPPER, LEAD, TIN, MERCURY, CHROMIUM, COBALT, MANGANESE : yielding, on heating, a malleable, or liquid (for mercury ores), metallic globule, as explained on pages 389-393, or else affording a decisive blowpipe reaction, proving the presence of one or more of these metals. A. Yielding a malleable globule B. B. on coal with, if not without, soda. 1. Compounds of Gold. 2. Compounds of Silver. 3. Compounds of Copper. 4. Compounds of Lead. 5. Compounds of Tin. B. Yielding drops of mercury with soda in a closed tube. 1. Compounds of Mercury. C. A decisive reaction with borax or salt of phosphorus for chromium, cobalt, or manganese. 1. Compounds of Chromium. 2. Compounds of Cobalt. 3. Compounds of Manganese. IV. MINERALS OF METALLIC OR SUBMETALLIC LUSTRE, NOT INCLUDED IN PRECEDING DIVISIONS. 1. Yielding fumes in the open tube or on coal, but not wholly vaporizable. 386 DETERMINATION OF MINERALS. A. Streak metallic. B. Streak unmetallic. a. Fumes sulphurous only. b. Fumes arsenical, with or without sulphurous. 2. Not yielding fumes of any kind ; streak unmetallic. A. B.B. easily fusible, giving a magnetic bead ; lustre sub metallic. B. Infusible, or nearly so. a. Reaction for iron ; anhydrous. b. Reaction for iron ; hydrous. c. Reaction for chromium or titanium, d. Reaction for osmium with nitre. V. MINERALS OF UNMETALLIC LUSTEE. 1. Having an acid, alkaline, alum-like, or styptic taste. A. CARBONATES : Taste alkaline ; effervescing with HC1. B. SULPHATES : No effervescence ; reaction for sulphur with soda. C. NITRATES : With sulph. acid, reddish acrid fumes ; no action with HC1 ; deflagrate. D. CHLORIDES : With sulph. acid, acrid fumes of HC1 ; no fumes with HC1. E. BORATES : No effervescence ; reaction for boron when moistened with sulph acid. 2. Not haying either of the above-mentioned kinds of taste. A. CARBONATES : Effervescing with HC1. a. Infusible ; assay alkaline after ignition. b. Infusible ; become magnetic and not alkaline, on ignition. c. Infusible ; B.B. on coal with soda, zinc oxide vapors. d. Infusible ; B.B. on coal reaction for nickel. e. Fusible ; assay alkaline after ignition. B. SULPHATES : Reaction for sulphur with soda, a. Fusible ; assay alkaline after fusion. b. Fusible ; reaction for iron. c. Infusible. DETERMINATION OP MINERALS. 387 C. ARSENATES : on coal arsenical fumes. D. SILICATES, PHOSPHATES, OXIDES : Species not included in the preceding subdivisions. X. STREAK DEEP RED, YELLOW, BROWNISH-YELLOW, GREEN, OB BLACK. A. Infusible, or fusible with difficulty. B. Fusible without much difficulty. H. STREAK GRAYISH OR NOT COLORED. 1. Infusible. A. Gelatinize with acid, forming a stiff jelly. B. Not forming a stiff jelly ; hydrous. a. Blue color with cobalt solution. 6. Reddish or pink color with cobalt solution. c. Not blue or red with cobalt solution. C. Not forming a stiff jelly ; anhydrous. a. Blue color with cobalt solution. b. Not blue or reddish color with cobalt solution. 2. Fusible with more or less difficulty. A. Gelatinize and form a stiff jelly. a. Hydrous ; fuse easily. b. Hydrous ; fuse with much difficulty. c. Anhydrous. a. No reaction for sulphur ; no coating on coal. ft. Reaction for sulphur with soda. B. Not gelatinizing. 1. Structure eminently micaceous ; folia tough, pearly, and H. of surface of folia not over 3*5 ; anhydrous or hydrous. 2. Structure not eminently micaceous. a. Hydrous. a. No reaction for phosphorus, or boron. |. H. =1 to 3 ; lustre not at all vitreous. ff. H.=3-5-6'5; lustre of cleavage sur- face sometimes pearly ; elsewhere vi- treous. ft. Reaction for phosphorus or boron. b. Anhydrous. a. B.B. lithium-red flame. ft. B.B. boron reaction (green flame). y. B.B. reaction for titanium. 8. B. B. reaction for fluorine or phosphorus. e. B.B. reaction for iron. . B.B. no reaction for iron : not of the pre- ceding subdivisions. 388 DETERMINATION OP MINERALS. I. ELEMENTS. 1. Lustre metallic ; liquid. MERCURY, p. 128. This is the only metallic mineral which is liquid at the ordinary temperature and atmospheric pressure. 2. Lustre metallic ; malleable and eminently sectile. GOLD, p. 109. G. =15-19-5 ; yellow ; fusible ; not sol. in nitric acid or HC1, but sol. in aqua regia. PLATINUM, p. 124. G.= 16-19 ; nearly white ; infusible ; insol. in nitric acid. PALLADIUM, p. 127. G.=ll-8-ll-8 ; grayish-white ; diff. fusible ; sol. in nitric acid. SILVER, p. 116. G. =10-11-1 ; white ; fusible ; sol. in nitric acid, and deposited again on copper. COPPER, p. 131. G.=r8'84; copper-red; fus.; sol. in nitric acid, and the solution becomes sky-blue when ammonia is added IRON, p. 171. G. 7-3-7-8; iron-gray; attracted by the magnet. The only other mineral of metallic lustre that is also malleable and eminently sectile is argentite, a silver sulphide, along with two others of like composition but different crystallization. 3. Lustre metallic ; brittle ; B.B. wholly volatile, but give off no sulphurous fumes. BISMUTH, p. 101. G.=9 73 ; reddish- white ; on coal a yellow coat- ing ; fumes inod. ANTIMONY, p. 100. G. =6'6-6'7; tin-white ; fumes dense wh., inod. ARSENIC, p. 98. G.=r5'9-6 ; tin-white ; fumes white, alliaceous. TELLURIUM, p. 96. G.=6'l-6'3 ; tin- white ; fus.; fumes white ; flame green. The only other mineral that is wholly volatile, and also gives off no sulphurous fumes, is allemontite, an antimony arsenide. 4. Lustre metallic ; H. =1-2 ; B.B. on coal infusible ; no fumes. GRAPHITE, p. 107. 5. Lustre unmetallic ; takes fire readily in the flame of a candle, and burns with a blue flame. SULPHUR, p. 94. 6. Lustre adamantine ; EL =10. DIAMOND, p. 103. Easily scratches corundum or sapphire. DETERMINATION OP MINERALS. 389 II. MINEKALS, NOT ELEMENTS, THAT ARE WHOLLY VOLATILE B.B. ON COAL. 1. Lustre metallic ; streak metallic. TETRADYMITE, p. 102. G. 7 2-7 '9 ; pale steel-gray; so soft as to soil paper ; on coal white fumes ; flame bluish-green; sometimes sulph. odor ; in open tube, a coating which fuses to white drops. BISMUTHINITE, p. 102. G.^6'4-7'2; whitish lead-gray; on coal yellow coating and sulph. odor. STEBNITE, p. 100. G. =4-5-4 52 ; lead-gray; on coal dense wh. fumes and wh. coating . 2. Lustre unmetallic ; streak same nearly as color. ORPIMENT, p. 99. Lemon yellow ; on coal burns, odor alliaceous. REALGAR, p. 99. Bright red ; on coal burns, odor alliaceous. ARSENOLITE, p. 99. White ; on coal, odor alliaceous. VALENTINITE, p. 101. White ; on coal dense wh. fumes, inott. CINNABAR, p. 128. Red ; in open tube, sulph. odor, coating of mercury globules. SALMIAK, p. 230. White ; saline and pungent taste ; on coal, fumes of ammonia. III. COMPOUNDS OF GOLD, SILVER, MER- CURY, COPPER, LEAD, TIN, CHRO- MIUM, COBALT, MANGANESE. A. Yielding a malleable globule B.B. on coal, with or without soda 1. COMPOUNDS OF GOLD. Yield gold, or an alloy of gold and silver, B.B. on coal. The TELLTJ- KIUM ORES, pp. 115, 116, give a coating of drops of tellurous acid in open tube. 2. COMPOUNDS OP SILVER. B.B. easily fusible ; G. above 5 ; yield, with few exceptions, a glo- bule of silver (white and malleable), on coal, with soda, if not without ; and, in the exceptions, silver globule obtained by cupellation. All have metallic lustre excepting cerargyrite, bromyrite, and iodyrite. 390 DETERMINATION OF MINERALS. a. EMINENTLY SECTILE. ARGENTTTE, p. 117. G.=7'2-7'4; lustre metallic ; on coal sulph. fumes. CERARGYRITE, p. 120. G. =5 '3-5 "6; lustre like that of white, gray, or greenish to brownish wax. &. NOT SECTILE ; ON COAL ODOROUS FUMES. SULPHIDES, p. 118. Gives sulph. odor. ARSENICAL ORES, pp. 119, 120. Alliaceous fumes. SELENIDES, p. 118. Horse-radish odor. C. NOT SECTILE ; ON COAL FUMES OF ANTIMONY OR TELLURIUM. ANTIMONIAL ORES, pp. 119, 120. Dense white fumes of anti- mony; with also, if sulphur is present, sulph. fumes. TELLURIDES, p. 118. In open tube coating which fuses to drops of tellurous acid. STROMEYERITE, p. 119. Contains copper, and requires cupellation in order to obtain a globule of silver. 3. COMPOUNDS OF COPPER. Unless iron is present, a globule of metallic copper is obtained with soda, if not without, on coal; with a nitric acid solution and ammonia in excess a bright blue color; moistened with HC1 the blue flame of chloride of copper; and a clean surface of iron in the nitric solu- tion becomes coated with copper. 1. METALLIC LUSTRE. SULPHIDES, pp. 132-136. On coal or in open tube sulph. fumes. ARSENIDES, SELENIDES, p. 135. ANTIMONIAL SULPHIDES, p. 135, 136. 2. LUSTRE UNMET AL]c ; B.B. NEITHER ON COAL NOR IN OPEN TUBE ANY ODOROUS FUMES ; NO TASTE. CUPRITE, p. 136. H. =3'5-4; G.=5'8-6'2; isometric; deep red, streak bnh-red. ATACAMITE, p. 136. Darkish bright green, streak gnh; B.B. on coal fuses, coloring O.P. azure-blue, with a green edge ; easily sol. in acids. PHOSPHATES, p. 139. MALACHITE, p. 140. H.=3-4; G.=3'7-4; light to deep green; ef~ fervesces with HC1. AZURITE, p. 141. H. =3 5-4-5; G.=3 5-3'9; deep blue ; effervesces with HC1. DIOPTASE, p. 141. H.=5; G. =3 25-3 35; emerald-green; B.B. in- fusible. CHRYSOCOLLA, p. 142. Bluish-green; B.B. infusible. DETERMINATION OF MINERALS. 391 3. LUSTRE T7NMETALLIC; B.B. ON COAL, OR IN CLOSED TUBE, ODOROUS FUMES OF ARSENIC OR SULPHUR, OR REACTION FOR SULPHUR. ARSENATES, p. 189. On coal arsenical fumes. CHALCANTHITEj p. 137. Blue; taste nauseous; astringent. Also Stromeyerite, Stannite, Bournonite give reactions for copper. 4. COMPOUNDS OF LEAD. Yield B.B. on coal a dark lemon-yellow coating ; finally, with soda, if not without, a globule (metallic and malleable) of lead is ob- tained ; but by continued blowing with O.F. the lead all goes off in fumes, leaving other more stable metals (silver, etc.) behind. Sul- phurous, selenious and tellurous fumes easily obtained either on coal or in an open tube from the sulphide, selenide, tellurides ; and arsenical or antimonial fumes from ores containing arsenic or anti- mony. None have taste. 1. LUSTRE METALLIC. GALENITE, p. 145. H. =2*5 ; O. =7*2-7 "7 ; cleavage cubic eminent ; lead-gray, streak same ; in open tube sulph. SELENIDES, TELLURIDES, ANTIMONIAL and ARSEN- ICAL SULPHIDES, page 149. 2. LUSTRE UNMET ALLIC ; NO ODOROUS FUMES, OR REACTION FOR SULPHUR. MINIUM, p. 149. Bright red, streak same. CROCOITE, p. 150. Monoclinic ; bright red, streak orange-yellow ; B.B. with salt of phosphorus emerald-green bead. PYROMORPHITE, p. 151. Hexagonal ; bright green to brown, rarely orange-yellow ; streak white. B.B. fuses easily, coloring flame bluish-green. CERUSSITE, p. 152. Trimetric, often in twins; H.=3-3'5; G.=6'4-68; white, gyh ; lustre adamantine; often tarnished to grayish metallic adamantine. Effervesces in dilute nitric acid. 3. UNMETALLIC ; REACTION FOR SULPHUR. ANGLE SITE, page 150. Trimetric ; white, gyh ; fuses in flame of candle ; B.B. reaction for sulphur ; no effervescence with acids. 5. COMPOUNDS OF TIN. CASSITERITE, p. 160. H.=6-7 ; G. =6 '4-7-1 ; brown, gyh, ywh, black; B.B. infusible; on coal with soda a globule of tin, yield no fumes. Stannite, p. 158. A copper, iron, and tin sulphide, does not give B.B. a metallic malleable globule. 392 DETERMINATION OP MINERALS. B. Yield drops of mercury in closed tube with or without soda. COMPOUNDS OP MERCURY. CINNABAR, p. 128. H.=2-2 5 ; G.=8-9 ; bright red, bnh red, gyh ; streak scarlet. AMALGAM, p. 117. H. =3-3-5 ; G. = 13-14 ; silver-white; yields silver B.B. on coal. Spaniolite, p. 136, a variety of tetrahedrite, yields mercury. C. No malleable globule ; decisive reaction with borax or salt of phosphorus for chromium, cobalt, or manganese. 1. COMPOUNDS OF CHROMIUM. Give with borax an emerald-green bead in both flames. CHROMITE, p. 180. H.=5'5 ; G.=4'3-4'5; isometric, often m octahedrons, massive ; submetallic ; bnh iron-black, streak brown ; B.B. on coal becomes magnetic ; with borax, a bead which is emerald-green on cooling. CROCOITE, p. 150. H.-25-3; O.=5'9-6'l; bright red, streak orange ; B.B. fuses very easily, on coal globule of lead, and with salt of phosphorus emerald-green bead. PhcBnicochroite and Vauque- Unite are other lead chromates. 2. COMPOUNDS OF COBALT. Give a blue color with borax after, if not before, roasting. [When much nickel or iron is present the blue color is not ob- tained ; and species or varieties of this kind are not here included.] 1. LUSTRE METALLIC. COBALTTTE, p. 165. H. 55; G.=6-6'3; isometric and pyrito- hedral ; rdh silver- white, streak grayish -black ; B.B. on coal sulph. and arsen. fumes, and a magnetic globule. SMALTITE, p. 1G5. H.=5'5-6; G.rr6'4-7'2; tin-white, streak gyh black ; B.B. on coal alliaceous fumes ; most varieties fail to give the blue color immediately with borax, because of the iron and nickel present. LINNJEITE, p. 164. H.=5'5; G.=4'8-5; isometric; pale steel- gray, copper-red tarnish, streak bkh gray. B.B. on coal sulph. fumes. 2. LUSTRE UNMETALLIC. ERYTHRITE, p. 167. H. = l 5-25 ; G.=295; monoclinic, one highly perfect cleavage, also earthy ; rose-red, peach-blossom red, streak reddish ; B.B. fuses easily ; yields water. DETERMINATION OF MINERALS. 393 BIEBERITE, p. 168. A cobalt sulphate. REMINGTONITB, p. 168. A hydrous cobalt carbonate. .3. COMPOUNDS OF MANGANESE. Give an amethystine globule in O.F. with borax. [The globule looks black if too much of the manganese mineral is used, and with a large excess may be opaque.] 1. GIVES OFF CARBONIC ACID WHEN TREATED WITH DILUTE H Cl ; LUSTRE UNMETALLIC. RHODOCHROSITE, p. 191. H.=35-4'5 ; G. =3 4^3 7 ; rose-red. Also manganese-bearing varieties of calcite, dolomite, ankerite, side- rite, all of which have the cleavage and general form of rhodochro- site ; when containing a few per cent, of manganese they often turn black on exposure. 2. TREATED WITH H Cl YIELDS CHLORINE FUMES. MANGANITE, p. 189. H.=4; G.=4'2-4'4; in oblong trimetric prisms ; grayish-black, streak reddish-brown ; lustre submetallic ; B. B. infusible ; yields water. PSILOMELANE, p. 189. H.=5-7 ; G. =3-7-4'7 ; amorphous ; black, streak brownish-black ; submetallic ; B.B. infusible ; yields water. Wad is similar, but often contains cobalt. PYROLUSITE, p. 188. H. 2-2 5 ; G.=4'82 ; in stoutish trimetric crystals ; metallic ; dark steel-gray, streak black or bluish-black ; B.B. infusible ; yields no water. BRAUNITE and HAUSMANNITE (p. 189) are other anhydrous manganese oxides. FRANKLINITE, p. 179. H. =5-5-6 5; G.=5-5'l ; in octahedrons and massive ; iron-black, streak dark reddish brown ; B.B. infusi- ble ; but little chlorine with H Cl. 8. C0 2 OR Cl NOT GIVEN OFF WHEN TREATED WITH HC1; AN HYDROUS. RHODONITE, p. 247. H.=5'5-6'5; G. =3 4-3 68; rose-red; B.B. fuses easily. TRIPLITE, p. 191. H.=5-5; G.=3'4-3'8; brown to black; B.B. fuses very easily, globule magnetic ; sol. in H Cl. HELVITE, p. 256. H.=6-65; G. =3 1-3 3; in yellowish tetrahe- hedrons ; B. B. fuses easily. SPESSARTITE (Manganesian Garnet), p. 258. H. =6'5-7 ; G =3'7- 4*4 ; in dodecahedrons and trapezohedrons ; red, brownish-red ; B.B. fuses easily. TEPHROITE, p. 256. H.=5'5-6; G.=4-4'12; reddish to brown and_gray ; B.B. fuses not very easily ; gelat. in H Cl. Mite, p. 256, is related, and also gelatinizes. 394 DETERMINATION OF MINERALS. HAUERITE, p. 188. H.=4; G.=3'46; isometric; reddish brown, streak brownish-red. B.B. yields sulphur, after roasting reaction for manganese. ALABANDITE, p. 188. H. =3'5-4 ; G. =4 ; submetallic, iron-black; streak green ; B.B. on coal sulphur, after roasting reaction for manganese. Vesuvianite, epidote, axinite, ilvaite, gothite, include varieties that give reaction for manganese. IV. MINERALS OF METALLIC OR SUB- METALLIC LUSTRE NOT INCLUDED IN PRECEDING DIVISIONS. 1. YIELDING FUMES IN THE OPEN TUBE OR ON COAL, BUT NOT WHOLLY VAPORIZABLE. A. STREAK METALLIC. MOLYBDENITE, p. 96. H.=l-l-5; G.=4'4-4'8 ; lead-gray, and leaves trace on paper ; B.B. on coal sulphurous fumes PISMUTHINITE, p. 102. H. =2 ; G.=6'4-7'2 ; lead gray, whitish ; B.B. on coal sulphurous fumes, and yellow bismuth oxide ; sol. in hot nitric acid and a white precip. on diluting with water B. STREAK UNMETALLIC. a. FUMES SULPHUROUS ONLY. PYRITE, p. 172. H. 6-6-5; G.=4'8-5'2: isometric and pyritohe- dral ; pale brass-yellow, streak gnh black, bnh black ; B.B. on coal, fuses to a magnetic globule. MARCASITE, p. 174. H.=6-6'5; G.-4-68-485; trimetric ; pale bronze-yellow ; streak gyh black, bnh black ; B.B. like pyrite. PYRRHOTITE, p. 174. H.=3'5-4-5; G. =4 4-4 -68; hexagonal; bronze-yellow, rdh ; streak gyh black; slightly magnetic; B.B. fuses to a magnetic mass. MILLERITE, p. 164. H.=3-3'5; G.=4'6-5'7, rhombohedral, usually in acicular or capillary forms, also in fibrous crusts ; brass- yellow, somewhat bronze-like ; B.B. fuses to a globule, reacts for nickel. LINNJEITE. p. 164. H.=5'5 : G.=4'8-5 ; isometric; pale steel- gray, copper-red tarnish ; streak blackish -gray ; B.B. on coal fuses DETERMINATION OF MINERALS. 395 to a magnetic globule, after roasting gives reactions for nickel, cobalt, and iron. SPHALERITE, p. 154. H.-35-4; G.=3'94'2; isometric; lustre submetallic ; streak nearly uncolored ; nearly infusible alone and with borax ; on coal a coating of zinc oxide. b. ARSENICAL FUMES, WITH OR WITHOUT SULPHUROUS. ARSENOPYRITE, p. 175. H.=5-6 ; G.=6-6'4 ; trimetric ; white, gyb, streak dark gyh black. In closed tube, red arsenic sulphide and metallic arsenic ; B.B. on coal fuses to magnetic globule. GERSDORFFITE, p. 166. H.^5'5 ; G.=5'6-6'9 ; isometric, py- ritohedral ; white, gyh, streak grayish -black. In closed tube arsenic sulphide, on coal not magnetic, and reacts for nickel and often cobalt. NICCOLITE, p. 166. H.=5-5'5; G. =7 '3-7 -7,* hexagonal ; pale copper-red, streak pale bnh black ; in open tube, coating of arsen- ous acid ; B.B. on coal no sulph. fumes, fuses to globule which re- acts for iron, cobalt and nickel. SMALTITE, p. 165. H.=:5'5-6 ; G. =6-4-7 '2 ; isometric ; tin-white ; streak gyh black ; on coal, no fumes of sulphur or only in traces. 2. NOT YIELDING FUMES OF ANY KIND. STEEAK UNMETALLIC. A. B.B. EASILY FUSIBLE, AND GIVING A MAGNETIC BEAD. LUSTRE SUBMETALLIC. ILVAITE, p. 263. H.=5'5-6; G.=3'7-4'2 ; trimetric; gyh iron- black, streak gnh or bnh black ; gelat. with H Cl. ALLANITE, p. 263. H. =5'5-6 ; G.=3 4 2 ; monoclinic ; bnh pitch- black, streak gyh, bnh ; B.B. fuses easily ; most varieties gelat. withHCl. WOLFRAMITE, p, 183. H.=5-5'5; G.=7'l-7'6; monoclinic; gyh black or bnh black ; B.B. fuses easily, and reacts for iron, manga- nese, and tungsten. B. INFUSIBLE OR NEARLY SO. a. REACTION FOR IRON ; ANHYDROUS; H.=5-6'5. MAGNETITE, p. 178. G.=4'9-5'2 ; isometric ; iron-black ; streak black ; strongly magnetic. MENACCANITE, p. 178. G. =4*5-5 ; rhombohedral ; iron-black : streak submetallic, black to bnh red ; very slightly magnetic. HEMATITE, p. 176. G.=4'5-5'3; rhombohedral ; gyh iron-black, in very thin splinters or scales blood-red by transmitted light; streak red ; sometimes slightly magnetic. MARTITE, p. 177. Same as hematite, but isometric. TANTALITE, p. 184. G.=7-8; trimetric; iron-black, streak rdh brown to black. 396 DETERMINATION OF MINERALS. FRANKLINITE, p. 179. H.=5'5-6'5; G.=4'8-5'l ; octahedral, massive ; iron-black ; streak dark rdli brown ; slightly attracted by magnet ; with soda reaction for manganese. COLUMBITE, p. 183. G. =5' 4-6 5; trimetric ; iron-black, gyh black, streak dark red to black, often with a bluish steel -tarnish. SAMARSKITB, p. 202. H.=5'5-7; G.=5'6-58; velvet-black, pitch-black ; streak dark rdh brown ; B.B. glows ; fuses with dif- ficulty. b. REACTION FOR IRON J HYDROUS ; LUSTRE SUBMETALLIC. LIMONITE, p. 181. G. =3-6-4 ; massive, often stalactitic and tube- rose with surface sometimes highly lustrous, often subfibrous in structure ; black, bnh black ; streak bnh yellow. GOTHITE, p. 182. G.=4'0-4-4; trimetric; also fibrous and mas- sive ; bkh brown ; streak bnh yellow. TURGITE, p. 182. G.-3-6-4'68 ; fibrous and massive, looking like limonite ; black, rdh black, streak red ; in closed tube decrepitates, which is not the case with gothite and limonite. C. REACTION FOR CHROMIUM OR TITANIUM. CHROMITE, p. 180. H.=5-5; G.=4'3-4'6; isometric; submetal- lic ; bnh iron-black, streak brown ; B.B. with borax gives a bead which on cooling is chrome-green. RUTILE, p. 162. H. =6-65; G.=418-4-25 ; black, streak bnh; reacts for titanium. Black varieties of brookite (p. 163), submetallic in lustre, give same reaction. Euxenite, p. 202 ; yttrotantalite, p. 202 ; cescliynite, p. 202 ; ferguson- ite, p. 202, and perofskite, p. 163, are submetallic in lustre. d. HEATED WITH NITRE IN A MATRASS YIELDS FUMES OF OSMIUM. IRIDOSMINE, p. 127. H.=6-7; G. =19-21 -2 ; in small scales from auriferous or platiniferous sands ; tin- white, gyh. V. LUSTKE UNMETALLIC. 1. MINERALS HAYING AN ACID, ALKALINE, ALUM-LIKE, OR STYPTIC TASTE. A. CARBONATES : Taste alkaline ; effervescing with HC1. NATRON, p. 229. Effloresces on exposure. TRONA, p. 230. Does not effloresce. DETERMINATION OF MINERALS. 397 B. SULPHATES : No effervescence; reaction B.B. on coal with soda for sulphur. MASCAGNITE, p. 231. Yields ammonia. MIRABIL1TE, p. 226. Monoclinic, crystals stout ; taste cool, saline, bitter ; B.B. flame deep yellow. EPSOMITU, p. 205. Trhnetric, crystals ordinarily slender, spicule- like ; taste bitter and saline ; B.B.' flame not yellow. ALUNOGOEN, p. 197. Taste like common alum. KALINITE, MENDOZ1TE and other alums, p. 198. MELANTERITE, p. 182. Green ; taste styptic ; reacts for iron. CHALCANTHITE, p. 137. Blue ; reacts for copper. MORENOSITE, p. 168. Green ; reacts for nickel. BIEBERITE, p. 168. Reddish ; reacts for cobalt. GOSLARITE, p. 156. White ; reacts for zinc. JOHANNITE, p. 171. Emerald-green, reacts for uranium. C. NITRATES : With sulphuric acid, reddish acrid fumes ; no action with hydrochloric acid ; deflagrate. NITRE, p. 228. Not efflorescent. Strong deflagration. SODA-NITRE, p. 229. Efflorescent. NITROCALCITE, p. 214. Deflagration slight. D. CHLORIDES : With sulphuric acid acrid fumes of HC1 ; no fumes with HC1. S ALMIAK, p. 230. Taste saline, pungent ; on coal, evaporates ; with soda, odor of ammonia. SYLVITE, p. 224. Taste saline ; B.B. flame purplish. HALITE or COMMON SALT, p. 224. Taste saline ; B.B. flame yellow. E. BORATES. No effervescence with acids ; B. B. reaction for boron, when moistened with sulphuric acid. SASSOLITE, p. 97. Taste feebly acid ; B.B. very fusible. BORAX, p. 227. Taste sweetish alkaline ; B.B. puffs up. 2. MINEKALS NOT HAYING AN ACID, ALKA- LINE, ALUM-LIKE OR STYPTIC TASTE. A. CARBONATES : Effervescing with HCL A. INFUSIBLE ASSAY ALKALINE AFTER IGNITION. p. 215. H. under .3 '5 ; G.=2'5-2'72; ft A R=W5 5', with three easy cleavages parallel to E; colors various ; effervesces readily with cold HC1 ; anhydrous. 398 DETERMINATION OF MINERALS. ARAGONITE, p. 218. H.=3'5-4; G.=2.94; trimetric, cleavage im- perfect ; otherwise like calcite. DOLOMITE, p. 219. H.=3'5-4 ; G.rr2'8-2'9 ; rliombohedral, Rf\R =106 15' ; colors various ; effervesces but slightly with cold HC1, unless finely pulverized ; anhydrous. MAGNESITE, p. 207. H. =3 5-4'5 ; G. =3-3'l ; rhombohedral, # A ,R =107 29' ; white, ywh, gyh ; effervesces but slightly with cold HC1 ; anhydrous. HYDROMAGNESITE, p. 207. H.=l-3 5 ; G.r=2 14-218 ; hydrous. B. INFUSIBLE ; BECOME MAGNETIC AND NOT ALKALINE AFTER IGNITION. SIDERITE, p. 185. H. =3 5-4 -5 ; G.=3'7-3'9 ; rhombohedral, R :R =107 ; cleavage as in calcite ; becomes brown on exposure, chang- ing to limonitf. ANKERITE, p. 186. H.=3'5-4; G.=2'9-3'l; #AjR=106 7' ; be- comes brown on exposure. Some kinds of calcite and dolomite contain iron enough to become magnetic on ignition. C. INFUSIBLE ; B.B. ON COAL WITH SODA, COATING OF ZINC OXIDE. SMITHSONITE, p. 156. H.=5; G.=4-45; rhombohedral like calcite; R/\R\QT 40' ; crystals often an acute rhombohedron ; anhydrous. HYDROZINCITE, p. 157. H.=2-2'5; G.^3'6-3'8; white, gyh, ywh, often earthy ; reacts for zinc ; hydrous. D. INFUSIBLE ; B.B. ON COAL REACTION FOR NICKEL. ZARATITE (Emerald nickel), p. 168. H.=3. Emerald green, streak paler. E. FUSIBLE ; ASSAY ALKALINE AFTER IGNITION. WITHERITE, p. 221. H.=3-3'75 ; G. =4 29-4 "35 ; trimetric ; white, ywh, gyh ; B.B. fuses easily, flame ywh green ; anhydrous. STRONTIANITE, p. 223 H.=3'5-4 ; G. =3 6-3 '72 ; trimetric ; pale green, gray, ywh, white ; B.B. fuses only on thin edges, flame bright red ; anhydrous. BARYTOCALCITE, p. 222. Monoclinic. G.=3'6 3 '66 ; B.B. nearly like witherite. Other carbonates are the Lead Carbonate, p. 152, and Copper Car- bonates, p. 140, included severally under the heads of LEAD and COP- PER, on page 391. DETERMINATION OF MINERALS. 399 B. SULPHATES or SULPHIDES : Reaction for Sulphur with Soda. A. FUSIBLE ; ASSAY ALKALINE AFTER FUSION. BARITE, p. 220. H.=2'5-3'5 ; G.=43 4'72 ; trimetric ; white, ywh, gyh, bluish, brown; B.B. decrepitates and fuses ; flame yellow- ish-green ; anhydrous. CELESTITB, p. 222. H.=3-3'5; G.=3'9-3'98; trimetric; white, pale blue, rdh ; B.B. fuses ; flame red ; anhydrous. ANHYDRITE, p. 211. H.=3-35; G.=2D-30; trimetric, with three rectangular and easy cleavages differing but slightly ; white, bluish, gyh, rdh, red ; B.B. fuses, flame reddish -yellow. GYPSUM, p. 210. H. =1-5-2; G.=2'3-235; monoclinic, one per- feet, pearly cleavage ; white, gray, but also brown, black from im- purities ; B.B. yields much water, becomes white and crumbles easily. B. FUSIBLE J REACTION FOR IRON. COPIAPITE, p. 182. H.=15; G. =2 '14; yellow ; on coal, becomes magnetic ; hydrous. Hauynite, p. 270, also gives the sulphur reaction with soda. C. INFUSIBLE, OR NEARLY SO. ALUMINITE, p. 199. H. 1-2 ; G. 1'66 ; adheres to the tongue ; white ; B.B. blue with cobalt solution. Alunite, p. 198, is similar, but H.=4, and G. =2 "58-2 75. SPHALERITE, p. 154. H.^3'5-4 ; G. =3 "9-4 '2 ; isometric ; light to dark resin -yellow ; B. B. on coal, coating of zinc oxide. G. AESENATE9 : Arsenical fumes on coal. SOORODITE, p. 185. H.r=3'5 4 ; G. =3- 1-3 3 ; trimetric ; leek-green to liver-brown ; B.B. fuses easily, flame blue, and with soda gives a magnetic bead ; on coal alliaceous fumes ; in H Cl. sol. PHARMACOSIDERITE, p. 185. H.=25; G.=:29-3; cubes and tetrahedrons ; dark green, bnh, reddish ; B.B. same as for scoro- dite. PHARMACOLITE, p. 214. H.^2-2'5 ; G. =2 6-2 75 ; wh, gyh, rdh ; monoclinic with one eminent cleavage ; B.B. fuses, flame blue ; on coal, alliaceous fumes ; after ignition assay alkaline ; in HC1 sol. 400 DETERMINATION OF MINERALS. D. SILICATES, PHOSPHATES, OXIDES : SPECIES NOT IN- CLTJDED IN THE THREE PRECEDING SUBDIVISIONS. I. Streak deep red, yellow, brownish-yellow, green or black. A. INFUSIBLE, OR FUSIBLE WITH MUCH DIFFICULTY. HEMATITE, p. 176. Red to black ; streak red ; B.B. reaction for iron ; magnetic after ignition in R. F. ; anhydrous. LIMONITE, p. 181. Brownish and ochre-yellow to black ; streak brownish -yellow ; B.B. gives off water, turns red, becomes mag- netic in R.F. TURGITE, p. 182. Brown to black ; streak red ; B.B. gives off water ; decrepitates ; becomes magnetic in R.F. FERGUSONITE, p. 202. Brownish black ; infusible. ZINCITE, p. 155. Red ; streak orange ; B.B. on coal, zinc oxide coating, and coating moistened with cobalt solution, green in R.F. B. FUSIBLE WITHOUT MUCH DIFFICULTY. WOLFRAMITE, p. 183. Grayish to brownish black ; streak dark reddish brown to black; lustre submetallic ; G. 1- 1-7 55. B.B. fuses easily, and becomes magnetic ; reaction for tungsten. VIVIANITB, p. 184. Blue to green (to white) ; streak bluish- white ; G. =2-5-2 '7 ; H. =15-2, hydrous ; B.B. fuses easily to mag- netic globule, coloring flame bluish-green. TORBERNITE, p. 170. Bright green, square tabular micaceous crystals ; streak paler green ; H.=2-2'5 ; hydrous ; yields a globule of copper with soda. SAMARSKITE, p. 202. H.=5"5-6; G.=56-58; velvet-black; streak dark reddish brown ; B.B. fuses on the edges. II. Streak grayish or not colored. 1. INFUSIBLE. A. GELATINIZE WITH ACID, FORMING A STIFF JELLY. CHRYSOLITE, p. 255. Yellow-green to olive -green, looking like glass; H.=67; G.=3'3-35; B.B. reacts for iron, becomes mag- netic ; anhydrous. CHONDRODITE, p. 281. H.=6-65; G. =3 '1-3 "25 ; pale yellow to brown, and reddish -brown ; lustre vitreous to resinous ; B.B. re- action for iron and fluorine ; anhydrous. ALLOPHANE, p. 296. H.=3; G.=1'8-1'9 ; always amorphous, never granular in texture; bluish, greenish ; B.B. infus., a blue color with cobalt solution ; hydrous. WiUemite, Calamine, Sepiolite, fuse with great difficulty, and are in- cluded under fusible gelatinizing species, p. 402. DETERMINATION OF MINERALS. 401 B. NOT FORMING A STIFF JELLY WITH ACID ; HYDROUS. #. Blue with cobalt solution (owing to presence of aluminum). WAVELLITE, p. 201. H.=3'25-4; G.=2'3-2-4; white to green, brown ; B.B. bluish-green flame after moistening with sulph. acid. LAZULITE, p. 199. H.=5'6; G.=3 3'1 ; blue; B.B. green flame, especially after moistening with sulph. acid ; hydrous. TURQUOIS, p. 200. H.=6 ; G. =2-0-285; sky-blue, pale green; B.B. flame green. KAOLINITE, p. 310. H.=l-2; G. =2 '4-2 65; white when pure; feel greasy ; B.B. flame not green. GIBBSITE, p. 194. H.=2'5-3'5 ; G.=2'3-2'4 ; white, grayish, green- ish ; B.B. flame not green ; soluble in strong sulph. acid. DIASPORE, p. 194. H. =6-5-7 ; G. =3'3-3'5 ; in thin foliated crys- tals, plates or scales; white, greenish, brownish ; B.B. flame not green ; soluble in sulphuric acid after ignition. b. Pale red or pink color, with cobalt solution (owing to presence of magnesium). BRUCITE, p. 204. H.=2'5; G.=2'3-245 ; pearly, white, green- ish ; foliaceous or fibrous and flexible ; B.B. after ignition, alkaline. c. Not blue or red with cobalt solution. OPAL, p. 239. H. =5-5-6-5; G.=l-9-2'3; B.B. with soda soluble with effervescence. GENTHITE, p. 309. H.=3-4; G.=2'4; pale green, yellowish; B.B. with borax a violet bead, becoming gray in R.F. owing to nickel ; decomp. by H Cl. CHRYSOCOLLA, p. 142. H.=2-4 ; G.=2 2'24 ; pale bluish-green to sky-blue ; B.B. flame emerald-green, and with soda on coal globule of copper. The micas, chlorites, chloritoid, and serpentine often fuse on their edges with much difficulty. C. NOT FORMING A STIFF JELLY ; ANHYDROUS. H.=5 to 9. a. Blue color with cobalt solution. CORUNDUM, p. 192. H.=9; G.=4; rhombohedral ; blue, white, red, gray, brown. CHRYSOBERYL, p. 196. H.=8'5 ; G.=3'7 ; gray, green, to eme- rald-green. TOPAZ, p. 286. H.=8; G.=3'5; in rhombic prisms with perfect basal cleavage, rarely columnar ; white, wine-yellow, and other shades. RUBELLITE, p. 283. H.=7'5 ; G.=3 ; in prisms of 3, 6, or 9 sides ; rose-red ; reaction for boron. ANDALUSITE, p. 284. H.=7'5; G.=3'2; always in prismatic crystals, often tesselated within, /A 7=93 ; grayish-white to brown. FIBROLITE, p. 285. H.=6-7 ; G.=3'2 ; columnar or fibrous forms and prismatic crystals with brilliant diag. cleavage. 402 DETERMINATION OF MINERALS. CYANITE, p. 286. H. 5-7 (greatest on extremities of crystals); G. 3'6 ; in long or short prismatic crystallizations, often bladed prisms ; pale blue to white and gray. LEUCITE, p. 271. H. =5'5-6 ; G. =2'5 ; white, gyh ; often in trapezo- hedral crystals. &. Not giving a blue or reddish color with cobalt solution ; H. = 8 to 5. SPINEL, p. 194. H.=8 ; G. =3'5 4'1 ; in octahedrons of red, green- ish, gray, black colors. Gahnite is similar, but with borax on coal, gives reaction for zinc. BERYL, p. 252. H.=7'5-8; G.=2'6-2'7; always in hexagonal prisms ; pale bluish and yellowish green, to emerald-green, also resin yellow and white, no distinct cleavage. ZIRCON, p. 259. H.=7-5 ; G. =4-4*75 ; dimetric, and often in square prisms ; lustre adamantine ; brown, gray. STAUROLITE, p. 291. H.=7; G.=3'4-3'8; in prisms of 123, and often in cruciform twins ; no distinct cleavage ; brown, black, gray. QUARTZ, p. 233. H.=7; G.=2'6; often in hexagonal crystals with pyramidal terminations ; of various shades of color. OPAL, p. 239, is in part anhydrous. MONAZITE, p. 203. H.=5-5'5; G.=4'9-5'3; in small brown im- bedded monoclinic crystals, with perfect basal cleavage ; B.B. flame bluish-green when moistened with sulph. acid. RUTILE, p. 162. H.=6-65; G.=4'15-4'25 ; dimetric; reddish- brown to brownish -red, green, black ; B.B. reaction for titanium. BROOKITE and OCTAHEDRITE, p. 163, are similar, except in crystal- line forms, and G. in brookite 4'0-4'2o, in octahedrite 3'8-3'95. PEROFSKITE, p. 163. H.=5-5 ; G.^4-4'1; yellowish, brown, black ; cubic and octahedral forms ; B.B. reaction for titanic acid. ENSTATITE, p. 244. H.=5'5 ; G.=3'l-3'3 ; in prismatic and fibrous forms with /A/=88 D 16', also foliated ; whitish, grayish, brown. Anthophyllite is similar, but /A 7=125% and it fuses on the edges with great difficulty. lolite, apatite, scheelite, eudase, fuse with much difficulty, and euclase gives some water in closed tube when highly ignited. 2. FUSIBLE WITH LITTLE OR MUCH DIFFICULTY. A. Gelatinize and afford a Stiff Jelly, a. Hydrous ; fuse easily. DATpLITE, p. 289. H.=5-5'5; G.=2'8-3; white, greenish, yel- lowish ; crystals glassy, stout, sometimes massive and porcellanous, never fibrous ; B.B. fuses easily, reaction for boron. NATROLITE, p. 299. H.=5-5'5 ; G.=2'3-2 4 ; in slender rhombic prisms, and divergent columnar ; white, y wh, rdh, red ; B.B. fuses very easily. SCOLECITE, p. 299. H.=5-5'5 ; G.=216-2'4; cryst. much like DETERMINATION OF MINERALS. 403 natrolite, but twinned, with converging striae on i-i as in figure on p. 299; B.B. sometimes curls up, fuses very easily. GMELINITE, p. 301. H. =4'5 ; G. =2-22 ; in small and short hex- agonal or rhombohedral cryst. ; B.B. fuses easily. PHILIPPS1TE, p. 302. H.=4-4'5 ; G. =2 "2 ; in twinned crystals ; B.B. fuses rather easily. LAUMONTITE, p. 293. H.=3'5-4 ; G.=2'2-2'4 ; white, reddish; crystals become white and crumbling on exposure to the air ; B.B. fuses rather easily. Pectolite (p. 293), and Analdte (p. 299), imperfectly gelatinize. &. Hydrous j fuse with much difficulty. CALAMINE, p. 157. H.=4'5-5 ; G.=3 15-319 ; white, greenish, bluish ; orthorhombic in crystals ; B.B fus. with great difficulty, re- action for zinc and none for iron ; hydrous. SEPIOLITE, p. 306. White ; soft and almost clay-like, also fibrous ; B.B. fuses with difficulty, with cobalt solution reddish ; hydrous. PYROSCLERITE, p. 317. H.=3 ; G.=2'74; micaceous ; B.B. fuses on thin edges. c. Anhydrous. a NO REACTION FOR SULPHUR ; NO COATING ON COAL. NEPHELITE, p. 269. H.=5'5-6 ; G.=2'5-2"65 ; hexagonal prisms and massive ; vitreous, with greasy lustre ; white, y wh, gyh brown, rdh ; B.B. fuses rather easily. WOLLASTONITE, p. 244. H =4'5-5 ; G. =2 "75-2 "9 ; white, gyh, rdh, bnh ; B.B. fuses easily. SODALITE, p. 270. H.=5'5-6; G.=2'13-2-4; white, blue, red- dish ; in dodecahedrons and massive ; B.B. fuses not very easily. WILLEMITE, p. 157. H.=5'5; G.=3'9-43; white to greenish, reddish, brownish ; B.B. glows and fuses with difficulty ; reaction for zinc and none for iron ; anhydrous. ft. REACTION FOR SULPHUR B.B. WITH SODA. HAUYNITE, p. 270. H.=5'5-6 ; G.=2'4-25 ; blue, greenish; iso- metric, in dodecahedrons, octahedrons ; B.B. fuses with some diffi- culty. DANALITE, p. 256. H. =5 "5-6 ; G. =3-427 ; isometric ; flesh-red to gray ; B.B. fuses rather easily, and gives reaction for manganese and zinc. B. Not Gelatinizing. STRUCTURE EMINENTLY MICACEOUS, SURFACE OF FOLIA MORE OR LESS PEARLY ; H. OF SURFACE OF FOLIA NOT OVER 3'5; ANHYDROUS OR HYDROUS. FSCOVITE, BIOTITE, PHLOGOPITE, LEPIDOLITE, LE. PIDOMELANE : for distinctions see pp. 266-268. Anhydrous, 404 DETERMINATION OF MINERALS. or affording very little water; B.B. fuse with difficulty on thin edges, excepting lepidomelane which fuses rather more easily. MAKGARODITE, DAMOURITE, p. 313. Much like common mica, but more pearly and greasy to the feel, folia not elastic ; giv- ing a little water in the closed tube ; color usually whitish. PENNINITE, RIPIDOLITE, PROCHLORITE, p. 318. Usually bright or deep green, blackish-green, reddish, rarely white ; folia tough, inelastic; B.B. diff. fus., reaction for iron and yield much water ; partially decomposed by acids. VERMICULITE, JEFFERISITE,p. 317. Brown, yellowish-brown, green ; exfoliate remarkably ; yield much water. MARGARITE, p. 319. H.-8;5-4'5 (highest on edges); G.=2-99; white, ywh, rdh ; folia somewhat brittle ; B.B. fuses on thin edges ; yields a little water. TALC, p. 304. FYROPHYLLITE, p. 306. Similar to talc; but B.B. exfoliates remarkably ; blue with cobalt solution. FAHLUNITE, p. 314, has often a more or less distinct micaceous structure. Autunite, p. 170, has a mica-like basal cleavage ; but it occurs in small square tables of a bright yellow color. Diallage, p. 246, has a structure nearly micaceous. Serpentine is sometimes nearly micaceous, but the folia are not easily separable and are brittle. Chloritoid has a perfect basal cleavage, but folia very brittle, and cleavage less easily obtained than in the preceding ; and moreover the mineral is infusible. 2. STRUCTURE NOT MICACEOUS. a. Hydrous. a. NO REACTION FOR PHOSPHORUS, OR BORON. t Hardness, with, the exception of a variety of serpentine, 1 to 3 ? lustre not at all vitreous, CHLORITES, p. 318. H.=2-25. Here fall the massive granular chlorites, olive-green to black in color, of the species penninite, ri- pidolite, prochlorite; B.B. reaction for iron, fuses with difficulty; yields much water. VERMICULITE, p. 317. H.=1-1'5. Granular massive forms of vermiculite. TALC, p. 304. H.=1-1'5. Here falls steatite (soapstone) or massive talc, of white to grayish green and dark green color, granular to cryptocrystalline in texture. B.B. fuses with great difficulty, and yields only traces of water ; no reaction for iron, or only slight. PYROPHYLLITE, p. 306. Grayish white, massive or slaty ; B.B. like the crystallized, p. 403, in its difficult fusibility and little water yielded, but does not exfoliate. SERPENTINE, p. 307. H.=2'5-4; G. =2 "36-2 '55 ; olive-green; ywh green ; blackish green, white ; B.B. fuses with difficulty on thin edges ; yields much water. DETERMINATION OF MINERALS. 405 FINITE, p. 312. H.=2-5-3'5; G.^2-6-2'85 ; lustre feebly waxy; gray, gnh, bnh. B.B. fuses; yields water. DAMOURITE, p. 313. Same as crystallized, p. 403, but in mas- sive aggregation of scales. tt Hardness 3 - 5 to 6'5 ; lustre often pearly on a cleavage surface, but elsewhere vitreous. PREHNITE, p. 295. H.=6-6'5; G.=2'8-3; pale green to white; crystals often barrel -shaped, made of grouped tables ; B.B. fuses very easily ; decomp. by H Cl. PECTOLITE, p. 293. K.=5 ; G.=2'68-2 8 ; white ; divergent fibrous, or acicular; B.B. fuses very easily; gelatinizes imperfectly with HC1. APOPHYLLITE, p. 294. H.=4'5-5 ; G.=2 3-2'4 ; white, gnh, ywh, rdh ; dimetric, one perfect pearly cleavage transverse to prism ; B. B. fuses very easily ; a fluorine reaction ; decomp. by H Cl. OHABAZITE, p. 300. H.=4-5 ; G.=2-2 2 ; rhombohedral, vitreous; white, rdh ; B. B. fuses easily ; decomp. by H Cl. HARMOTOME, p. 301. H.=4'5; G.=2'44; white, ywh, rdh; crystals twins, usually cruciform ; B.B. fuses not very easily ; vitre- ous in lustre ; decomp. by H Cl. STILBITE, p. 302. H.=3'5-4 ; G.=2-2 2 ; white, ywh, red ; crys- tallizations often radiated-lamellar ; one perfect pearly cleavage ; B. B. exfoliates, fuses easily ; decomp. by H Cl. HEULANDITE, p. 303. H.=35-4; G.=22; in oblique crystals, with one perfect pearly cleavage ; B.B. same as for stilbite. EUCLASE, p. 288. H. =7-5 ; G. =81 : in glassy transparent mono- clinic crystals; B.B. fuses with great difficulty ; gives water in closed tube when strongly ignited. Prehnite, apopliyllite, chabazite, harmotome, heulandite, and enclose never occur in fibrous forms. ft. REACTION EITHER FOR PHOSPHORUS OR BORON. VIVIANITE, p. 184. H.=15-2; G.=2'55-7; monoclinic with one perfect cleavage ; white, blue, green ; B.B. fuses very easily, the flame bluish green, a gray magnetic globule ; in H Cl sol. ULEXITE, p. 212. H.=l; G. =1 -65 ; white, silky, in fine fibres ; B.B. fuses very easily, and moistened with sulph. acid flame for an instant green, "owing to the boron present ; little sol. in hot water. PRICEITE (p. 212) is in texture and color like chalk ; similar to ulexite in green flame B.B. Borax and Sassolite are other soft minerals containing boron, but these have taste. I. Anhydrous. a. B.B. the flame lithium-red. SPODUMENE, p. 248. H.=6'5-7; G.=813-8'19; white, gyh, gnh white, monoclinic (like pyroxene), with /A 7=87, and perfect cleavage parallel to 7 and i-i; B.B. swells and fuses. 406 DETERMINATION OF MINERALS. PETALITE, p. 248. H.=6-6'5; G.=2-4-2'5; white, gray, rdh, gnh ; B.B. becomes glassy and fuses only on the edges. HEBRONITE, AMBIiYGONITE, p. 199. H. =6 ; G. =3-31 ; moun- tain green, gyh, white, bnh ; B.B. fuses very easily, reaction for fluorine. TRIPHYLITE, p. 190. H.=5 ; G.=3'5-3'6 ; greenish gray, bluish, often bnh black externally ; B.B. fuses very easily, globule mag- netic ; with soda, manganese reaction. LEPIDOLITE, p. 268. H.=2 5-4 ; G.=2'8-3 ; micaceous, also scaly- granular; rose-red, pale violet, white, gyh; B.B. fuses easily; after fusion gelat. with H Cl. Some Uotite, p. 266, gives the lithia reaction. (3 . B.B. boron reaction (green flame). TOURMALINE, p. 282. H.=7 ; G.=2 9-3'3 ; rhombohedral, prisms with 3, 6, 9 sides, no longitudinal or other distinct cleavage ; black, blue black, green, red, rarely white ; lustre of dark var. resinous ; B.B. fusion easy for dark var. and diff. for light. AXINITE, p. 264. H. =6*5-7 ; G.=3 27 ; triclinic, sharp-edged, glassy crystals ; rich brown to pale brown and grayish ; B.B. fuses readily ; with borax violet bead. BORACITE, p. 206. H.=7 ; G.=2'97 ; isometric ; white, gyh, gnh ; lustre vitreous ; fuses easily, coloring flame green. Dariburite, p. 264, is another boron silicate. y. B.B. reaction for titanium. TTTANTTE, p. 290. H.=5-5'5 ; G.=3'4-3'56 ; monoclinic ; usually in thin sharp-edged crystals ; brown, ywh, pale green, black ; lustre usually subresinous ; B.B. fuses with intumescence. 3. Reaction for fluorine or phosphorus. CRYOLITE, p. 197. H.=2'5 ; G.=2'9-3 ; white, rdh, bnh ; fuses in the flame of a candle ; soluble in sulph. acid which drives off hydro- gen fluoride, a gas that corrodes glass. FLUORITE, p. 208. H.=4; G.=3-3'25; isometric, with perfect octahedral cleavage, and massive ; white, wine-yellow, green, pur- ple, rose-red, and other bright tints ; phosphoresces ; when heated, decrepitates ; B.B. fuses, coloring the flame red ; after ignition, alkaline. Lepidolite (p. 268), Amblygonite (p. 199), also give a fluorine re- action. APATITE, p. 212. H.=4'5-5 ; G. =2 '9-3 '25 ; often in hexagonal prisms ; pale green, bluish, yellow, rdh, bnh, pale violet, white ; B.B. fuses with difficulty, moistened with sulph. acid and heated, flame bluish green from presence of phosphorus ; sometimes reaction for fluorine. S. Reaction for iron. GARNET, p. 256. H. =6 "5-7 "5 ; G.=3'15-4'3 ; isometric, usually in dodecahedrons and trapezohedrons, also massive, never fibrous or columnar ; red, bnh red, black, cinnamon red, pale green, to emerald- DETERMINATION OP MINERALS. 407 green, white. B.B. dark-colored varieties fuse easily, and give iron reaction, but emerald-green var. almost infusible ; a white to yellow massive garnet is hardly determinable without chemical analysis. VESUVIANITE (Idocrase), p. 261. H.-6'5 ; G. =3*35-3-45 ; dimetric and often in prisms of four or eight sides, never fibrous ; brown to pale green, ywh, bk ; B.B. fuses more easily than garnet ; reaction for iron. EPIDOTE, p. 262. H.=6-7; G.=3'25-3'5; in monoclinic cryst. and massive, .rarely fibrous ; unlike amphibole in having but one cleavage direction ; ywh green, bnh green, black, rdh, yellow, dark gray ; B.B. fuses with intumescence. AMPHIBOLE, dark varieties including Jwrriblende, actinolite, and other green to gray and black kinds, p. 249. H.--=5'6 ; G.=3-3'4 ; monoclinic, in short or long prisms, often long fibrous, lamellar, and massive, prisms usually four or six sides, /A/=124i, cleavage par. to 1 ; B.B. fusion easy to moderately difficult. ANTHOPHYLLITE, p. 252, like hornblende ; bnh gray to bnh green, sometimes lustre metalloidal ; B.B. fuses with great diffi- culty. PYROXENE, augite, and all green to black varieties, p. 245. ^ H.=5-6 ; G.=r3'2-3'5 ; monoclinic, in short or oblong prisms, lamel- lar, columnar, not often long, fibrous or asbestiform, prisms usually with four or eight sides, /A 7=87 5', cleavage par. to 1 ; B.B. as in hornblende. HYPERSTHENE, p. 244. H.=5-6; G.=3'39; cryst. nearly as in pyroxene, but trimetric, usually foliated massive, also fibrous ; bnh green, gyh black, pinchbeck-brown ; B.B. fuses with more or Jess difficulty. Bronzite, p. 244, is similar and almost infusible. IOLITE, p. 264. H.=7-7'5 ; G. =2 "6-2 7 ; blue to blue violet ; looks like violet-blue glass ; B.B. fuses with much difficulty. Tourmaline, much Titanite, and lhaite (p. 263), B.B. give iron re- action. C. No reaction for iron. SCHEELITE, p. 212. H.=4'5-5 ; G.:=5-9-6-l ; ywh, gnh, rdh, pale yellow ; lustre vitreous-adamantine ; fuses on the edges with great difficulty. SCAPOLITES, p. 268. H.=5'5-6; G.=2'6-2'74; dimetric, often in square prisms ; white, gray, gnh gray ; B.B. fuses easily with in- tumescence. ZOISITE. p. 263. H=6-6'5; G. 3'l-3'4; trimetric, oblong prisms and lamellar massive, cleavage in only one direction. AMPHIBOLE, white var. (tremolite), p. 249. Same as for other amphibole (above), except in color ; B.B. fuses. PYROXENE, white var., p. 215. Same as for other pyroxene (above), except in color ; B.B. fuses. ORTHOCLASE, p. 278. H.=6-6'5 ; G.=2'4^2'62 ; monoclinic, stout cryst., and massive, never columnar, two unequal cleavages, the planes at right angles with one another, and cleavage surfaces never finely striated, as seen under a pocket lens or microscope ; white, gray, flesh-red, bluish, green ; B.B. fuses with some difficulty. 408 DETERMINATION OF MINERALS. ALBITE, p. 277, OLIGOCLASE, p. 276. H.=6; G.=256-2'72; triclinic, but cryst. as in orthoclase, except that the two cleavage planes make an angle of 93i to 94, and one of them has the surface striated ; white usually, flesh-red, bluish ; B.B. fuse with a little difficulty ; not acted on by acids. LABRADORITE, p. 276. H.=:6 ; G.=2'66-2'76 ; triclinic, like albite in cryst., and nearly in cleavage angle, 93 20', and in striae of surface ; white, flesh -red, bnh red, dark gray, gyh brown ; B.B. fuses easily ; decomposed by HC1 with difficulty. ANORTHITE, p. 275. H =6-7 ; G.=2'66-2'78 ; cryst, and stria? as in albite, cleavage angle 94 10' ; white, gyh, rdh ; B.B. fusion difficult ; decomposed by HC1 with separation of gelat. silica. MICROCLINE, p. 278. Very near orthoclase in all characters, but triclinic, cleavage angle differing only 16' from a right angle, and surface of most perfect cleavage striated, but striae exceedingly fine, often difficult to detect with a good pocket lens, and requiring the aid of a polariscope ; color white, gray, flesh-red, often green. For optical distinctions of FELDSPARS, see p. 274. EUCLASE, p. 288. H. =7'5; G.=8'l ; in monoclinic crystals, with one perfect diagonal cleavage ; pale green, to white, bnh ; trans- parent ; becomes electric by friction. ON ROCKS. I. CONSTITUENTS OF EOCKS. ROCKS are made up of minerals. A few kinds consist of a single mineral alone : as, for example, limestone, which may be either the species calcite or dolomite ; quartzyte (along with much sandstone), which is quartz ; WDAfelsyfe t which is orthoclase. But even these simple kinds are sel- dom free from other ingredients, and often contain visibly other minerals. Nearly all kinds of rocks are combinations of two or more minerals. They are not definite compounds, but indefinite mixtures, and hardly less indefinite than the mud of a mud-flat. The limits between kinds of rocks are consequently ill-defined. Granite graduates insensibly into gneiss, and gneiss as insensibly into mica schist and quartzyte, syenyte into granite, mica schist into hornblende schist, granite also into a compact porphyry-like rock, and trachyte; and so it is with many other kinds. The fact is a chief source of the difficulty in studying and defining rocks, and especially the crystalline kinds. The different rocks are not species in the sense in which this word is used in science, but only kinds of rocks. The minerals which are the chief constituents of rocks are of two classes : (A) the Siliceous; (B) the Calcareous. A. The siliceous are as follows : 1. Quartz, which probably makes up one-third of the rocky material of the crust of the globe. 2. The Feldspars (p. 272) ; of which orthoclase (with microcline) is most abundant ; next to it, oligoclase and labradorite ; and next alb it e, andesite, and anortMte. 3. The Micas (p. 205) : muscovite and biotite, of equal prominence, the others much less common. 4. Ampliibole and Pyroxene species (p. 245, and beyond) : especially hornblende or black amphibole, and augite or 409 410 DESCRIPTIONS OP ROCKS. black pyroxene ; also the green hornblende or actinolite; the green foliated hornblende called xmaragdite, and the foli- ated pyroxene sometimes wrongly called hypersthene, and another variety called diallage; also occasionally the species Jiypersthene and cnstatite. 5. The Felclspar-rlike minerals, nepJielite (p. 269) and leu- cite (p. 271), which are related in constituents and quan- tivalent ratios to the feldspars, alumina being the only ses- quioxide base, and lime, potash, and soda the protoxide bases afforded in analyses ; the atomic ratios for the protoxides, sesquioxide, and silica being in nepheiite, 1 : 3 : 4, as in anorthite ; and in leucite 1 : 3 : 8, as in andesite. Also, less abundantly, Sodalite (p. 270), which has essentially the ratio of anorthite and nephelite. 6. Minerals of the Saussurite group. These jade-like species differ from the feldspars (1) in being always fine- grannlar in texture; (2) in having a high density, G-. #9-3 '4 ; in varying from the feldspar type chemically. They are near some soda-lime feldspars in constituents, but not ahvays in the atomic relations of the constituents, nor in the absence uniformly of magnesia. There are two prominent kinds. One is between anorthite and zoisite in composition (see p. 263) ; yet, unlike .these minerals, its analyses afford several per cent, of soda and some magnesia. The second approaches labradorite ; Delesse obtained for a specimen from Mt. Genevre (Alps), Silica 49 '73, alumina 29*65, iron protoxide 0*85, magnesia 0*56, lime 11*18, soda 4-04, potash 0*24, water (with a little C0 2 ) 3-75 ; and a Silesian specimen afforded Vom Rath nearly the same result. A third kind from Corsica, according to Boulanger's analy- sis, has nearly the same composition as zoisite. A. fourth is jadeite (p. 263), a stone occurring in the Swiss lake-dwell- ings but not yet found in the saussurite rocks of Switzer- land. The saussurite of Siberia and the Alps has been observed to have sometimes the form of twins of a triclinic feldspar. This, and the texture, density, and composition, show that saussurite is, in part at least, pseudomorphous, and, in somo regions, after labradorite. By some peculiar conditions in the process of metamorphism perhaps long-continued heat with an unusual amount of moisture the feldspar crystal- lizations that formed in the incipient stages of the process were afterward changed to a species of higher density and DESCRIPTIONS OP ROCKS. 411 different molecular nature ; in other words/to saussurite. Some of the material appears to be still labradorite. 7. The iron-bearing minerals, Epidote (p. 262), Garnet (p. 250), Chrysolite (p. 255), which characterize some varie- ties of rocks. B. The calcareous species are calcite or calcium carbonate (p. 215), in various states of impurity ; and dolomite or cal- cium-magnesium carbonate (p. 219), which in its rock-form is undistinguishable in external aspect from calcite. Gypsum, or hydrous calcium sulphate, is also a consti- tuent of beds among rocks, and should have its place in the list, although not strictly embraced under the term calca- reous. Of the siliceous minerals, orthoclase (with microcline), and the two micas, muscovite and biotite, are related in com- position, in that each affords 10 per cent, or more of pot- ash. Leucite is another allied potash-alumina silicate, even richer in potash than orthoclase, it containing 17 to 21 per cent. The rocks characterized by these minerals are hence rich in potash. Albite and oligoclase, and also sodalite, afford much soda, the first two usually 8 to 12 per cent. , and sodalite, 20 to 25 per cent. Nephelite (elaeolite) is also a soda mineral related to the feldspars ; but, with 15 to 16 per cent, of soda, there are 5 or 6 of potash ; rarely the alkali afforded is all soda. The ordinary kinds of hornblende and pyroxene, on the contrary, afford little or no soda or potash. They thus dif- fer widely from the potash and soda species just mentioned, and naturally characterize for the most part a distinct series of rocks. Much importance has been allowed in lithology to the distinction of foliated under the species hornblende and pyroxene ; when, in fact, neither in mineralogy, as all treatises admit, nor in lithology, has it more than a very subordinate value. The character obtained this distinction before it was fully understood that the foliated forms were identical in composition with those in crystals or in massive forms. Hornblende does not differ from augite in composition ; but since the difference in crystallization is connected with a difference in the physical conditions attending their origin, DESCRIPTIONS OF ROCKS. and since rocks of each kind often have a vast extent over the earth's surface, the distinction as to whether a rock is hornblendic or augitic is of prominent geological interest. II. CLASSES OF ROCKS. Kocks are of different classes, according to their texture and origin. 1. FBAGMENTAL. A large part of common rocks were formed of sand, or pebbles and sand, and are only consoli- dated sand-beds or gravel-beds ; and other related kinds are more or less consolidated mud-beds or clay-beds. The mud- beds of an estuary, or of the shallow seas off a coast, and the stratified sand and gravel accumulations of sea-shores and valley formations, are precisely the kind of material which by consolidation have made the fragmental rocks, the most abundant rocks of the earth's surface. Each pebble, grain of sand, and constituent particle of the mud, was derived from preexisting rocks, and is either an actual fragment from those rocks, or else a fragment altered by more or less com- plete decomposition. The rocks are hence called fragmen- ted. The pebbles, and often the sands, have a worn surface, and this fact, together with the structure of the beds, affords evidence that they are fragmental. They are also the sedi- mentary rocks of geology ; for the material was for the most part carried and dropped by waters as sediment is carried and dropped the waters mainly of the ocean which then covered the continents. 2. CKYSTALLINE. Other rocks are crystalline. The grains are angular instead of worn, and they crowd upon or pene- trate one another because made in one process of crystal- lization. They are generally angular over a fractured sur- face because of the cleavage planes, like the grains of a surface of broken iron. Granite, trap, white marble are ex- amples of crystalline rocks. When such a rock is distinctly granular there is little difficulty in deciding upon its being a crystalline rock. If too fine-grained for a positive conclu- sion with the aid of a pocket-lens, the doubt may usually be removed by tracing it along to places where it is coarser ; and if none such offers, by the preparation of thin slices for microscopic examination. Crystalline rocks have received their crystalline texture in different ways. DESCRIPTIONS OF ROCKS. 413 A. By cooling from fusion. The rocks thus made are called IGNEOUS or ERUPTIVE rocks, as, for example, lavas or vol- canic ejections, and all rocks that, like trap, have come up melted through fissures in the earth's rocky crust. The depth of the liquid source of such eruptions is unknown. The fact that, at one epoch, material of the same kind has sometimes been ejected at intervals along a band of country a thousand miles in length, from northeast to southwest, as on the Atlantic coast from Nova Scotia to South Carolina, indicates considerable depth in such cases. They may be older rocks melted over and thrust up to the surface ; but if so, the remelted rocks were in many cases those situated deep in the earth's crust, far below all the strata of its surface. B. By subjection to long -continued heat without fusion, making METAMORPHIC rocks. Through this means fragmen- tal or sedimentary strata, over areas of thousands of square miles, and many thousands of feet in depth, have been simultaneously crystallized, turning the beds that were originally made from sand, gravel, or mud, into granite, gneiss, and other related rocks, and compact limestones into marble. The rocks at the time of the change were generally undergoing extensive mountain-making uplifts, and it is supposed that the friction attending the movements of the strata may have been an important source of heat for the change or crystallization ; and that the diffusion of this heat was due to the moisture which abounds in unaltered sedimentary beds. Metamorphic strata retain their former relative order of superposition, having been crystallized in place, that is, without fusion. Where granite has been the result, it is probable that the material was sometimes re- duced to a pasty state, so that all lines of the original bed- ding were obliterated ; but even in that case, the granite is generally in the place occupied by the material before crys- tallization. In other cases, including that of some granites, there was not even this degree of approach toward the origi- nal condition of the true eruptive rock. During the upturn- ing, the rocks were much fractured, and the fissures so^made became filled with the materials of the adjoining or subjacent rocks, through the aid of the heated moisture present, mak- ing veins ; and such veins differ widely from those, called 'dikes, that were made when the fractures descended to re- gions of melted rock, so that the fissures became filled with ejected material. 414 DESCRIPTIONS OP ROCKS. Rocks thus metamorphosed or rendered crystalline are distinguished as metamorphic rocks. C. By chemical deposition. Waters often hold calcareous material in solution. When carbonic acid (carbon dioxide) is present in any waters, those waters will take up calcium carbonate, and make calcium bicarbonate ; and when the waters evaporate, the calcium carbonate is deposited. This is the propess by which stalactites and stalagmites (p. 216) have been made, and so also calcareous tufa and travertine (p. 432). The Gardiner River region in the Yellowstone Park is noted for its deposits of travertine. In geyser regions there are siliceous deposits made by the hot waters, as stated on page 240 ; and these also are exem- plified in the Yellowstone Park. Beds of tripolite (p. 241) sometimes become consolidated and converted into chert by the waters that penetrate them these waters containing a trace of alkali or enough to enable them to dissolve some of the tripoli silica, and then a deposition taking place causing consolidation. The flint and chert of the rocks has probably had generally this ori- gin. 3. CALCAREOUS ROCKS or LIMESTONES. Compact lime- stones are commonly of fragmental origin. They have been made mainly out of worn or ground-up shells, corals, and like calcareous material of organic origin the movements of the ocean having been, and still being, the grinding agency. They were consolidated through the ocean's waters which penetrated the beds taking up a little calcareous material, and then depositing it again. It is, in one sense, metamor- phism. But when such compact limestones experience true metamorphism, at the same time with other strata, they be- come distinctly crystalline-granular, and often very coarsely so, making crystalline limestone or marble. III. ON SOME CHARACTERISTICS OF ROCKS. 1. CRYSTALLINE TEXTURE. Crystalline texture varies in coarseness from that in which crystalline grains are visible only under high magnifying power, and the rock is as apha- nitic (p. 60) as flint, to that in which they are very coarse. Not unfrequently one of the minerals appears in large crys- tals, distributed through the mass the mass being made of DESCRIPTIONS OF HOCKS. 415 the rest of the material in a comparatively fine-grained con- dition. The porphyry of the ancients was a rock of dark feldspathic base, sprinkled all through with light-colored feldspar crystals ; and, from this fact, any metamorphic or igneous rock containing such disseminated crystals of a feldspar is said to be porphyritic. The following figures illustrate three varieties of porphy- ritic rock. The first represents a specimen of the red an- tique porphyry of Egypt now often called Rosso antico the rock which gave the name porphyry to geology, a kind Rosso Antico. Oriental Verd-antique. Porphyritic gneiss. much used by the Romans (though not by the Greeks or Egyptians), and quarried by them in the mountain Djebel- Dokhan, twenty-five miles from the lied Sea, in latitude 27 20'. Through the red aphanitic base small whitish crystals of orthoclase are thickly distributed. Figure 2 is from a polished piece of green antique poryphyry. The feldspar crystals are comparatively large, and the compact base has a dark green color. Figure 3 represents a large crystal of orthoclase with the gneiss about it, from porphy- ritic gneiss. The feldspar crystals in porphyritic gneiss or granite sometimes measure three inches by one and a half, and again only a fraction of an inch. These orfchoclase crystals, as often in other porphyritic rocks, are twin crys- tals, the plane of cleavage of one half making an angle of 52 23' with that of the other half. Occasionally large crys- 416 DESCRIPTIONS OF ROCKS. tals contain small crystals of mica distributed in one or more layers concentric with the sides. The clegree of coarseness in the texture of a crystalline rock has been determined chiefly by the rate of cooling, in connection with the nature of the material. Relatively rapid cooling produces a fine texture or grain, and very slow cooling a coarser. A melted rock may cool too rapidly to become stony throughout, or to become stone at all; and, in the latter case, the material made is glass. Common melted glass would be stone on cooling if the process were gradual enough. Figures 4 to 6 represent much-magnified views afforded by transparent slices from glassy rocks, in three of their stages between the pure glassy and the true stony state. In 4, from obsidian, or volcanic glass, of Greenland, there are radiating clusters consisting of hair-like microiites (or microscopic minerals), called tricliites (from the Greek tlirix, hair), such as are common in all obsidians. Fig. 5 shows the texture of a variety of pearlite, a light gray rock of 6. Tricliites in ob- sidian. Trichites and Fluidal texture in Pearlite. Microiites in a Pitchstone from Weisselberg. pearly lustre from the Montezuma Range in the Nevada Basin, as figured by Zirkel; in this, trichite clusters, besides being very numerous, are arranged in lines or planes, and some of the tricliites arc powdered with pellucid grains, or globnlites, which are incipient crystals. Zirkel represents another kind in which the radiating trichites are each a string of globulites. Fig. 6 represents a pitchstone from DESCRIPTIONS OP ROCKS. 417 Weisselberg (from Rosenbusch), in which the microlites are distinctly crystalline in form, and some give evidence that they are feldspar crystals, others that they are augite and magnetite, and indicate that the rock is intermediate be- tween a glass and a doleryte. Thus there is a passage to ordinary stone. Trap or doleryte has been used for making bottle-glass ; and attempts have been made to manufacture glass directly from a variety of granite containing little quartz. Eruptive rocks, that have come up through fissures, often have glassy particles among the stony in the part near the walls of the fissure when not so through the inte- rior of the mass; and many such rocks, covering large areas, have glassy grains among the stony grains, or a glassy mag- ma, because the cooling generally was not slow enough for complete lapidification ; or they have an undefined base, when examined in thin slices, which the microscope does not resolve into crystalline grains. !Such portions of a rock are described as unindivi dualized. An unindividualized base exists in the basalt of Truckee Valley, the character of a slice from which, highly magnified, is given in fig. 7, from Zirkel ; feldspar crystals, of their usual rectangular forms (part of them sanidin), one of the largish crystals of chryso- lite, and smaller irregularly-shaped augites, are imbedded in a base which consists of a glass-like substance ; and in this material there are extremely small globulite grains which are globules of devitrified glass or incipient crystals. The glassy unindividualized base occupies the spaces among the crystalline portions. v rhese differences in crystalline texture are of small im- portance compared with differences in mineral and chemi- cal composition. They are results of accidents, and, at the best, lead only to a distinction of varieties among kinds of rocks. The presence of a little glass, or of disseminated large crystals in a porphyritic way, does not make the rock essentially different in kind. If, however, the glassy na- ture is manifest in the external appearance of the mass, ib is convenient to call the rock by a separate name. Porphyritic rocks are sometimes named as if porphyry was a distinct kind of rock, or as if the porphyritic section of a kind of rock merited special prominence. But, as re- cognized beyond, "felsyte-porphyry " is porpliyritic felsyte ; f ( dioryte-porphyry" is porpliyritic dioryte ; " diabase-por- 418 DESCRIPTIONS OF ROCKS. phyry "is porpliyritic diabase, or, since diabase cannot be distinguished mmeralogically from doleryte, it is porpliy- ritic doleryte ; and, in these and other like cases, the being porphyritic is a characteristic of minor value. Sometimes igneous rocks exhibit under the microscope a fluidal texture; that is, the material, when examined in sections, shows wavy lines or bands, which are evidence of a former fluid state, and of movement or flowing when in that state. One variety of this texture is represented in fig- ure 8 (from Zirkel), giving a magnified view of an eruptive 7. 8. ill Basalt with the base unindividu- alized. " Rhyolyte ;" Fluidal texture. rock from the head of Louis Valley, Nevada ; and another in figure 5, p. 416. Such rocks have been comprised under the general name of Rhyolyte (from the Greek for flowing) ; but this fluidal texture is' presented by rocks of different mineral constitution, and is hence not a proper basis for a kind of rock. 2. ANHYDROUS AND HYDROUS CRYSTALLINE ROCKS. Some eruptive rocks, like doleryte or trap, occur both an- hydrous and hydrous. The latter, unlike the former, have the constituent minerals clouded in aspect, however thinly sliced, and often changed in part to a green chlorite a hy- drous mineral and also sometimes to other hydrous species. Such rocks, moreover, have less lustre, and very frequently they are amygdaloidal that is, contain little cavities that are often almond-shaped (the Latin amygdalum meaning DESCRIPTIONS OF ROCKS. 419 almond), which were made by steam, or vapor of some kind, and are now occupied by minerals. This hydrous or chloritic condition is due to alteration, and hence such rocks are properly only varieties of the anhydrous instead of being distinct kinds. The change was probably occasioned by subterranean wa- ters, such as exist as streams among the earth's strata, that were encountered by the liquid rock when on its way up a fissure toward the surface. Hydrostatic pressure prevented the waters from being driven back by the heat, and conse- quently th* vapors were forced to penetrate the igneous mass. In the region of New Haven, Conn. lying at the south extremity of the Connecticut Valley the Triassic trap-dikes of the western border of the region, and those outside of the Trias, east or west, in the metamorphic rocks, are anhydrous, while those in the middle of the valley and east of this are mostly hydrous, showing a difference in exposure to the waters according to the geographical position of the dikes in the valley. Of two parallel ranges of dikes, not half a mile apart, and following concentric curves in their courses (situated twenty miles and more north of New Haven), one (as Percival recognized) is amygdaloidal and hydrous, and the other nearly anhydrous; and the positions of the two kinds, there and elsewhere in the Connecticut Valley, indicate a general relation between the direction of the present valleys and that of the subterranean water-chan- nels of Mesozoic time. In very many places coal-like " inspissated bitumen" occurs in the amygdaloidal cavities, which was apparently derived from mineral oil that the action of the heat on the Triassic carbonaceous shales (in some places abounding in fossil fishes) had caused to rise in vapors and penetrate the melted rock. The carbonic acid of the calcite that so often constitutes the amygdules probably came from the action of the heat on limestone encountered at the same time. The deoxidizing action of the carbohydrogen vapors is sup- posed by J. Lawrence Smith to account for the metallic iron found in some trap or doleryte. The minerals which constitute the amygdules (see p. 297) are largely such as may have been made by the aid of heat and moisture out of the minerals of the rock itself at the points where they occur. The water that caused the change could not have come from above after the rock was cooled ; for the slight surface decomposition the 420 DESCRIPTIONS OF ROCKS. anhydrous trap now undergoes shows that such waters do not make their way down : and moreover the results could not have been pro- duced without heat. The trap has not been subjected to a metamor- phic process ; for the Triassic beds are unaltered sandstone. The water was not from the deep-seated source of the erupted trap, for, if so, the dikes would have been all of one kind, instead of being part hydrous and part anhydrous, and the former locally distributed just as subter- lanean streams of water are likely to be. In the case of hydrous metamorphic rocks, whether con- taining chlorite, talc, or a hydrous mica, the hydrous min- erals were, with rare exceptions, made at the time of the crystallization, and are not a consequence of subsequent al- teration. 3. DURABILITY IK ROCKS. Durability in a rock is due largely (1) to compactness and fineness of texture; and (2) to the absence of any ingredient or mineral that is liable to oxidation. As far within a rock as water and air can gain access, degradation will always be going on, and most rapidly in all crevices along their walls. Alternate melting and freez- ing will be one means of destruction ; direct chemical action of moist air, especially the carbonic acid it contains (p. 108), another ; the wedging apart of grains caused by the slightest deposits and oxidations, through infiltrated waters, another. In granite the carbonic acid may take the alkalies out of the feldspar, and so occasion the destruction of the rock. Hence the practice of testing the durability of a stone for architectural purposes, by putting it into water, and then weighing it, after some days of exposure, to see whether it has gained in weight, is a good one. Fineness of grain gives further protection against destruc- tion. Alternate heating and cooling in the daily passage of the sun is a destroying agency of great effect, especially 011 coarse-grained kinds. Eocks have often retained the glacier markings upon them perfectly fresh until now, when they have had a covering of two or three feet of earth ; and they have lost such markings after a few years of exposure. This happens often where there is no true decomposition or ox- idation of the surface portion of the rock, and must be due largely to the expansion and contraction caused by changing temperature. The finer the grain of the rock the less the chance for this action. There is no more durable rock than a roofing-slate of good quality. Granites, when well pol- ished, will usually resist long all weathering agencies. DESCRIPTIONS OF ROCKS. 421 The presence of an oxidizable ingredient is a common source of destruction. Pyrite occurs in grains or crystals in almost all kinds of rocks ; and it generally oxidizes easily whenever water and air get access to it. Only the firmest crystals resist change, and these not always. A rock containing even a little pyrite can seldom be trusted for architectural purposes. If a limestone contain a few per cent., or even one, of iron or manganese replacing part of the calcium, it has a source of destruction within it. The iron and manganese are sure, after a while, to oxidize ; the iron will give rusty stains, and the manganese turn it black, and both will work destruction. A chemical trial is needed to ascertain the fact as to the purity or not of the rock. The presence of iron carbonate (siderite or spathic iron) is the occasion, wherever it exists, of rapid decomposition as far down as moisture and air can reach. This has been one source of the changes producing the great beds of limonite (like those of Western Massachusetts, Salisbury, Connecti- cut, and other places), in which the rocks are sometimes de- composed to a depth exceeding one hundred feet. It is a fact to be remembered that a rock which has stood the weather for centuries in its native exposure is a safe material for man's structures ; and one that is crumbling is worth little or nothing. Durability depends much on the climate. In Peru, even sun-burnt bricks will last for centuries. The resistance to crushing in rocks is ascertained by sub- jecting cubes of a given size to pressure. 'In recent experi- ments by P. Michelot,* Minister of Public Works in France (whose trials numbered over 10,000), the most compact limestones, weighing 2,700 kilograms per cubic meter, were crushed by a weight of 900 kilograms per square centimetre. Compact oolitic limestone of Bourgogne and some other French localities, weighing 2,600 to 2,700 kilograms, bore 700 to 900 kilograms before crushing. Statuary and decora- tive marbles bore 500 to 700 kilograms. Of granitic rocks from Brittany, the Cotentin, the Vosges, and the Central Plateau of France, weighing 2,600 to 2,800 kilograms, the best, which admitted of polishing, bore 1,000 to 1,500 kilograms; while the coarser granites of Brest and * Exposition Universelle de 1873 a Vieimc, p. 401-432 ; and Annales des Pont* et Chaussees, 1863, 1868, 1870. 422 DESCRIPTIONS OF ROCKS. Cherbourg and the syenyte of the Vosges bore 700 to 1,000 kilograms ; and other coarse granites, in which the large crystals of feldspar were in part decomposed, bore only 400 to 600 kilograms. The green porphyry of Ternuay (Haute Saone), bore 1,360 kilograms; the "basalt of Estelle (Puy de Dome), 1,880 kilograms. In trials by Gen. Gilmore, trap of New Jersey required to crush it 20.750 to 24,040 Ibs. a square inch (about 6 c. m. sq.) ; granite of Westerly, R. I., 17,750 ; id. of Rich- mond, Va., 21.250 ; syenyte of Quincy, 17,750 ; marble of Tuckahoe, N. Y., 12,950 ; id. of Dorset, Vt., 7,612 ; lime- stone of Joliet, 111., 11,250 ; sandstone of Belleville, N. J-, 10,250; id. of Portland, Ct., 6,950; id. of Berea, 0., 8,300; id. of Amherst, 0., 6,650 ; id, of Medina, N. Y., 17,250 ; id. of Dorchester, N. B., 9,150. When absorbent rocks are thoroughly wet the weight re- quired to crush them is greatly reduced. To crush wet chalk, according to trials by Delesse, required only one-third what it did when stove-dried ; and for the limestone, " calcaire grossier," of Vitry and other localities, mostly one- third to one-half. Tournaire and Michelot found, for the chalk of the Paris basin, the pressure required when wet two-ninths of that required when the rock had been dried at a tempera- ture considerably above 212 F. Use of the Microscope in the Study of Rocks. The study of thin, transparent slices of rocks by the microscope is of in- terest whether the crystalline rock be coarse or fine in tex- ture ; but it is particularly important when of the latter kind. There is no rock so opaque that it cannot be made transparent, or at least translucent, in thin slices. Such slices are examined by means of a polariscope-microscope. The increased use of the microscope in the investigation of rocks has led to the introduction, by way of distinction in methods of study, of the word macroscopic. An investiga- tion may be carried on macroscopically , that is, without the use of a microscope, excepting a pocket lens ; or microscopi- cally, that is, by the study of thin slices through the aid of the microscope and polariscope. The more important points ascertained by microscopic methods, as regards the mineral constitution of a rock, are the following : 1. The presence or not of quartz; of a feldspar; of a chloi'ite. DESCRIPTIONS OF ROCKS. 423 2. The distinction of a triclinic feldspar from ortlioclase, the former showing in sections, cut in any direction ex- cepting one, commonly several parallel spectrum bands, due to multiple twinning in the crystal, while orthoclase shows no bands of the kind, or at the most but two. 3. The presence or not of hornblende ; this mineral hav- ing often cleavage lines meeting at angles of 124, and being dichroic. 4. The presence or not of pyroxene ; this mineral often showing cleavage lines meeting at angles of 87 (nearly a right angle), and being not dichroic, and usually distin- guished in this way from hornblende. 5. The presence or not of mica, its cleavage lines and dichroism affording distinctive characters. G. The presence or not of chrysolite ; of magnetite, its form being often octahedral, and single or grouped ; of 11. Magnetite in grouped Liquid Carbonic Cube of Salt in a solu- crystals. Acid. tion of the same. points or portions having the nature of glass, and therefore not polarizing light; of fluidal lines; of liquid carbonic acid, and of various other inclusions. Fig. 9 shows a common form of the grouping of microscopic magnetite crystals in an eruptive rock. Fig. 10 represents a cavity in quartz nearly filled with a liquid, b the small bubble, c, showing the part not occupied by it. When the liquid is carbonic acid the air-bubble disappears on raising the temperatw-e to 86-95 F. Carbonic acid requires a pressure, at 32 F., of 38-J- atmospheres to retain it in the liquid state ; and hence occurs liquid only in quartz, topaz, and a few other miner- als. Fig. 11 (from Zirkel) shows another cavity, containing, besides a liquid, a little cube and microscopic hornblende- like acicular crystals ; and the cube is supposed to be com- mon salt in a solution of salt. Hexagonal prisms of apa- tite (calcium phosphate) are detected by the microscope in 4.24: DESCIUI'TIONS OF HOCKS. almost all kinds of igneous and metamorpliic rocks, includ- ing trap or doleryte. For a particular account of the distinguishing character- istics of minerals studied by microscopic methods, reference must be made to treatises on the subject. IV. KINDS OF ROCKS. 1. Eocks are generally mixtures of two, three, or four prominent mineral constituents, with also others, it may be, of less importance. Each mineral adds a distinctive fea- ture, and might be a reason for a new name. But it is usual with lithologists to base the distinction into kinds of rocks on the two chief minerals, and make the others acces- sory species and the basis only of varieties. This method is prompted by convenience, and also by the fact that the more important characteristics are commonly contained in two of the constituent minerals. It has many exceptions, however, and particularly where a third mineral has special peculiarities and abundance. 2. Difference in kind of rock is naturally based on dif- ference in chemical or mineral constitution, and identity, accordingly, on essential identity in this respect. Conse- quently when there is no essential difference in chemical or mineral constitution, there is no sufficient reason for a dis- tinction in kind or a difference in name, unless the wide distribution of a particular variety, and the permanence in its characters, make the distinction in name a geological necessity. In accordance with this statement, the distinctions among crystalline rocks of coarse or fine in texture ; of being por- phyritic or not ; of containing glassy grains among the stony or not ; of being foliated or not in crystallization, are of little value compared with the real mineral constitution, anda^p a fit basis only, at the best, for varieties. But the two rocks of like composition, trachyte and felsyte, retain their characteristics so widely, that geology needs both names, and only demands that" their essential identity should be held in mind. The same kind of rock is in many cases both of metamor- phic and eruptive origin ; still the difference of origin is not a sufficient basis for a distinction of kind unless there is some marked difference between them, and an extended KINDS OF ROCKS. 425 distribution of each, that makes the case like that of tra- chyte and felsyte. The author has proposed to use the pre- fix meta for metamorphic kinds when a rock occurs both metamorphic and eruptive ; but this is not intended to indi- cate a distinction in kind, but only to abbreviate the qualify- ing word metamorphic. According to the principles above stated, a rock having oligoclase or albite as its feldspar constituent cannot rightly have the same name with one having either of the basic feldspars, labradorite or anorthite, as an essential part, although these feldspars are all embraced under the decep- tive title of playioclase (p. 275). Between anorthite and oligoclase there is a difference of 20 per cent, in the silica, and the former is simply a lime feldspar ; and the contrast is large also between labradorite and oligoclase. Again, for a like reason, as already explained (p. 411), a mica-bearing rock containing little or no hornblende cannot properly be classed with hornblendic rocks. 3. It has been supposed that pre-Tertiary crystalline rocks differed so decisively from the Tertiary and more recent, that those of the two series should not bear the same name. But geology knows nothing of any epoch of sudden transi- tion in the mineral nature of eruptive rocks at the com- mencement of the Tertiary era ; on the contrary, it shows that the kinds made before and after this epoch are alike in mineral constitution, and differ not always even in tex- ture, but only in the greater prevalence after the Tertiary of volcanic or subaerial ejected masses, and therefore of rocks of the texture this involves. The distinction of doleryte from diabase, with others similar, is of this chronological kind. Rocks, like other objects in science, should evidently be named from what they are, and not from the age in which they may have been made. 4. Since quartz is the most abundant of all the minerals of the globe, it is the least characteristic of the ingredient^ of compound rocks. Eecent lithologists have made it, in sev- eral cases, distinguish only a section under a kind of rock. Thus, there are dioryte and quartz-dioryte, felsyte and quartz- felsyte, trachyte and quartz-trachyte. On the same principle there are syenyte and quartz-syenyte, as adopted beyond. 5. The division of crystalline rocks into acidic and basic rocks is explained on p. 274 The acidic afford on analysis 426 DESCRIPTIONS OF ROCKS. 55 per cent, or more of silica, and the basic usually less than 52. 6. The feldspars are divided, according to their bases, into (1) potash-feldspars, including orthoclase and micro- cline ; and (2) those which may be designated soda-lime- feldspars, namely the species albite, oligoclase, andesite, labradorite, and anorthite, which yield either soda, or lime, or both, on analysis. The term plagioclase has been used for the latter ; but it is no longer applicable since microcline is plagioclase. Under the heading potash-feldspars, as used beyond, leucite also is included ; and under that of soda- lime-feldspars, nephelite and sodalite, and also the minerals of the saussurite group. The kinds of rocks are described under the heads of 1. FRAGMENTAL BOCKS, EXCLUSIVE 6F LIMESTONES. 2. LIMESTONES, OR CALCAREOUS EOCKS. 3. CRYSTALLINE EOCKS, EXCLUSIVE OF LIMESTONES. No strongly denned limit exists between the fragmental and crystalline rocks. But still they are for the most part widely diverse in character and aspect. In the names of rocks, the termination ite is here changed to yte, as done in the author's " System of Mineralogy " (1868), in order to dis- tinguish them from the names of minerals. Granite is excepted. I. Fragmental Rocks, exclusive of Limestones. 1, Conglomerate. A rock made up of pebbles or of coarse angular fragments of rocks of any kind, (a) If the pebbles are rounded, the conglomerate is a pudding-stone ; (b) if angular, a breccia. Conglomerates are named according to their constituents, siliceous or quartzose, granitic, calcareous, porpltyritic, pumiceous, etc. 2r Grit. A hard, gritty rock, consisting of coarse sand, or sand and small pebbles, called also millstone grit, be- cause used sometimes for millstones. 3. Sandstone. A rock made from sand : a consolidated sand-bed. VARIETIES. a. Siliceous or Quartzose ; consisting chiefly of quartz. b. Granitic; made of granitic material or comminuted granite, c. Mi- caceous ; containing much mica. d. Argillaceous; containing much clay with the sand. e. Gritty ; hard and containing small quartz peb- KINDS OF ROCKS. 427 bles. f . Ferruginous ; containing iron oxide and having its red color, g. Concretionary ; made up of concretions, h. Laminated ; made up of thin layers or laminae, or breaking into thin slabs, a characteristic most prominent in argillaceous sandstones, i Friable ; crumbling in the fingers, j. Fossitiferous ; containing fossils. The paving stone extensively used in New York and the neighbor- ing States is a laminated sandstone, of the upper part of the Hamilton group in geology, quarried just south of Kingston, and at many other places on the west side of the Hudson River. The rock is remarkable for its very even lamination. In Western New York and in Ohio, the Devonian sandstones, above the Hamilton group, together with the Waverly group, afford a similar flag-stone. The " brown-stone" used much in New York and elsewhere for buildings, is a dark-red sand' stone from the Triassic formation, and is quarried at Portland, Conn., on the Connecticut River, opposite Middletown. A lighter-colored " brown-stone " or "free-stone," of the same age, also much used for buildings, comes from Newark, Belleville, Little Falls, and other points in Central New Jersey. The handsome sandstone of light olive-green tint, much employed in architecture, is from the Lower Carboniferous group in New Brunswick. The soft white sandstone, in much esteem among architects because so easily cut and carved, comes from Ohio quarries, in beds of the Carboniferous ; it is mostly from a bed about sixty feet thick, called the " Berea grit/' and is obtained at Bereaand Independence in Cuyahoga County, and Amherst in Lorain County, and elsewhere. Pyrite is often present in sandstones used for building, and has de- faced, and is destroying, many a beautiful structure by its oxidation, and the consequent decay of the rock. Sandstones absorb moisture most easily in the direction of the bed- ding or grain, if there is any distinct bedding ; and hence the blocks, when used for a building or wall, should be placed with the bedding horizontal. It is, further, the position in which the stone will stand the greatest pressure. Grindstones are made from an even-grained, rather friable sand- stone, and are of different degrees of fineness, according to the work to be done by them. Hard siliceous sandstones and conglomerates, occurring in regions of metainorphic rocks, are called " granular quartz," and quartzyte (p.435). 4. Sand-rock. A rock made of sand, especially when not of siliceous material. A calcareous sand-rock is made of cal- careous sand ; it may be pulverized corals or shells, such as forms and constitutes the beaches 011 shores off which living corals and shells are abundant. The beach sands become cemented below high- water mark into a calcareous sand-rock, which consists of layers having the pitch of the surface of the beach. They are often coarse, calcareous conglomerates. 5. Shale. A soft, fragile, argillaceous rock, having an uneven slaty structure. Shales are of gray, brown, black, dull -greenish, purplish, reddish and other shades. 428 DESCRIPTIONS OF ROCKS-. VARIETIES. a. Bituminous shale, or Carbonaceous sliale (Brand* schiefer of the Germans), impregnated with coaly material and yielding mineral oil or related bituminous matters when heated, b. Alum shale; impregnated with alum or pyrites, usually a crumbling rock. The alum proceeds from the alteration of pyrite or the allied pyrrhotite (p. 174). 6. Argillyte, or Phyllyte. An argillaceous slaty rock, like shale, but differing in breaking usually into thin and even slates or slabs. Roofing and writing slates are exam- ples. It is sometimes thick-laminated. Unlike shale, it occurs in regions of metamorphic rocks, and often graduates into hydromica, chloritic, and mica schists, and also, on the other hand, into shale. Often called Clay-slate. VARIETIES. a. Bluish-black, b. Tile-red, c. Purplish, d. Grayish. e. Greenish; f. Ferruginous, g. Pyritiferous. h. Thick-laminated; affording thick slabs, instead of slates, i. Thick-bedded; a massive rock, affording thick blocks or masses, j. Staurolitic. k. Ottr clitic. Extensive quarries of slate exist in Vermont at Waterford. Thet- ford, and Guilford, in the eastern slate range of the State ; in North- field in the central range, and in Castleton and elsewhere in the western range, the last of Lower Silurian age if not the others. There are excellent quarries also in Maine and Pennsylvania. The rock fur- nishes also thick slabs for various economical purposes. A trial as to water absorption, and a clos'e examination as to the presence of pyrite, is required before deciding that a slate rock is fit for use, how- ever even its fissile structure. Kinds with a glossy surface are most likely to be impervious to moisture. 7. Tufa. A sand-rock or conglomerate made from com- minuted volcanic or other igneous rocks, more or less altered. Usually of a yellowish-brown, gray, or brown color, some- times red. VARIETIES. a. Dolcrytic or basaltic; tufa made from those igneous rocks that contain iron-bearing minerals, such as doleryte (trap), basalt, and the heavier lavas ; it is usually yellowish-brown or brown in color, sometimes red ; and often consists in part of palagonite (p. 312). b. Trachytic; made of the f eldspathic igneous rock, trachyte, of an ash- gray color, or of other light shades, c. Pumiceous ; made of frag- ments of pumice. Pozzurtana- is a light-colored tufa, found in Italy. near Borne, and elsewhere, and used for making hydraulic cement, Wacke is an earthy brownish rock, resembling an earthy trap or dole- ryte, usually made up of trappean or dolerytic material, compacted into a rock that is rather soft. 8. Sand. Gravel. Sand is comminuted rock-material ; but common sand is usually comminuted quartz, or quartz and feldspar, while gravel is the same mixed with pebbles and stones. Sand often contains grains of magnetite, or KINDS OF ROCKS. 429 of garnet, or of other hard minerals existing in the rocks of the region. Occasionally magnetite or garnet is the chief constituent. Volcanic sand, or Peperino, is sand of volcanic origin, either the "cinders" or "ashes" (comminuted lava), formed by the process of ejection, or lava rocks otherwise comminuted. 9. Green Sand. An olive-green sand-rock, friable, or not compacted, consisting largely of glauconite. See, for de- scription and analysis, p. 307. 10. Clay. Soft, impalpable, more or less plastic material, chiefly aluminous in composition, white, gray, yellow, red to brown in color, and sometimes black. It has been made chiefly from the feldspars, by decomposition. See Kaolinite. VARIETIES. a. Kaolin, purest unctuous clay. b. Potter's day, plastic, free from iron ; mostly unctuous ; usually containing some free silica. Pipe-day is similar, c. Fire-brick day, the same ; but it may contain some sand without injury, d. Ferruginous, ordinary brick day, containing iron in the state of oxide or carbonate, and con- sequently burning red, as in making red brick, e. Containing iron in the state of silicate, and then failing to turn red on being burnt, as the clay of which the Milwaukee brick are made. f. Alkaline and Vitri- fidble, containing 2 '5 to 5 per cent, of potash, or potash and soda, owing to the presence of undecomposed feldspar, and then not refrac- tory enough for pottery or fire-brick, g. Marly, containing some car- bonate of calcium, h. Weak clay, containing too much sand for brick- making, i. Alum -bearing, containing aluminous sulphates, owing to the decomposition of iron sulphides present, and hence used for mak- ing alum. The red pipestone of the North American Indians is an indurated clayey rock^from the Coteau de Prairies ; it has been named Catlinite; and the gray is in part compact argillyte. 11. Alluvium. Silt. Till. Alluvium is the earthy deposit made by running streams or lakes, especially during times of flood. It constitutes the flats either side, and is usually in thin layers, varying in fineness or coarseness, being the re- sult of successive depositions. Silt is the same material deposited in bays and harbors, where it forms the muddy bottoms and shores. LCBSS is a fine earthy deposit, following the courses of valleys or streams, like" alluvium, but without division into thin layers. Occurs in elevated plains, along the broad parts of large valleys, as the Mississippi, Rhine, Danube. Till is the unstratified sand, gravel, and stones, derived from glaciers. 430 DESCRIPTIONS OF ROCKS. Detritus (from the Latin for worn) is a general term ap- plied to earth, sand, alluvium, silt, gravel, because the ma- terial is derived, to a great extent, from the ivear of rocks through decomposing agencies, mutual attrition in running water, and other methods. Soil is earthy material mixed with the results of vegeta- ble and animal decomposition, whence it gets its dark color and also a chief part of its fertility. 12. Tripolyte (Infusorial Earth). Eesembles clay or chalk, but is a little harsh between the fingers, and scratches glass when rubbed on it. Consists chiefly of siliceous shells of Diatoms with often the spicules of sponges. Forms thick deposits, and is often found in old swamps beneath the peat. This soft diatomaceous material is sold in the shops under the name of silex, electro-silicon, and polishing powder, and is obtained for com- merce in Maine, Massachusetts, Nevada, and California. A bed ex- ceeding fifty feet in thickness occurs near Monterey in California ; and other large beds in Nevada near Virginia City, and elsewhere. It is used as a polishing powder ; in the manufacture of "soluble glass;" and also mixed with nitro-glycerine to make dynamite. Occurs some- times slaty, as at Bilin, Prussia ; and also hard or indurated, from con- solidation through infiltrating waters, and thus graduates, at times, into chert. Consists of silica in the opal or soluble state. II. Limestones or Calcareous Rocks. 1. NOT CRYSTALLINE. 1. Limestone. Calcyte Compact uncrystalline limestone usually of dull gray, bluish-gray, brownish, and black colors, sometimes yellowish-white, cream-colored, nearly white, and red of different shades ; in texture, varying from earthy to compact semi-crystalline. It consists essentially of cal- cite or calcium carbonate (p. 215), but often contains clay or sand, or other impurities. VARIETIES. The varieties depending on color are very numerous, and many of them, when pure and compact, are polished and used for marble. The gray and black colors are due commonly to carbo- naceous material, for they burn white ; but the yellow, red, and some other kinds to the presence of iron, oxide. There are also : a. Fossil- iferous or shell limestone, b. Coral or Madreporic limestone, c. En- dinital or Crinoidal limestone; containing crinoidal remains in the form mostly of small disks, d. Ntfmmulitic ; containing the disk- shaped fossils called Nummulites. e. Oolitic limestone ; a limestone having an oolitic texture, f. Bird's - eye limestone ; having small whitish crystalline points scattered through it, a rock of Western KINDS OF ROCKS. 431 New York, of the Trenton period in geology, g. Conglomerate lime- stones. The black marble of the United States comes mostly from Shore- ham, Vermont, and other places in that State, near Lake Champlain, and from near Plattsburg and Glenn's Falls, N. Y. ; also from Isle La Motte. A pudding-stone marble, of various dull shades of color, occurs on the banks of the Potomac, in Maryland, 50 or 00 miles above Washington ; it is used for columns in the interior of the Capitol at Washington. The Portor is a Genoese marble very highly esteemed ; it is deep black, with veinings of yellow ; the most beautiful comes from Porto- Venese. The Nero-antico marble of the Italians is an ancient deep black marble ; the paragone is a modern one, of a fine black color, from Bergamo ; and panno di morte is another black marble with a few white fossil shells. A beautiful marble from Sienna, brocatello di Siena, has a yellow color, with large irregular spots and veins of bluish-red or purplish. The mandelato of the Italians is a light red marble, with yellowish- white spots. The Madreporic marble is the Pietra stellaria of the Italians. Fire-marble, or lumachelle, is a dark brown shell marble, having brilliant fire-like or chatoyant reflections from within. Ruin marble is a yellowish marble, with brownish shadings or lines arranged so as to represent castles, towers, or cities in ruins. These markings proceed from infiltrated iron. It is an indurated calcareous marl, and does not occur in large slabs. Hydraulic limestone is a compact kind containing some clay, and affording a quicklime the cement from which will set under water. An analysis of a kind from Rondout, N. Y., afforded Carbonic acid 34-20, lime 25 50, magnesia 12 '35, silica 15 '37, alumina 9*13, iron sesquioxide 2 '25. In making ordinary mortar, quartz sand is mixed with pure quicklime and water, and the chemical combination is mainly that between the water and lime, together with subsequently an absorption of carbonic acid. With " hydraulic cement," silica and alumina (that of the clay) are disseminated through the lime, and hence these ingredients enter into chemical union with the lime and water, and make a much firmer cement, and one which " sets " under water. Oil-bearing limestones occasionally occur. A kind used for build- ing in Chicago, of the Niagara period, becomes spotted or streaked with blackish mineral oil, after a few years' exposure to the weather. Some of the pyramids of Egypt, including the largest, the pyra- mid of Cheops, is made of nummulitic limestone ; and this is tLe building material of Aleppo, the range of mountains between Aleppo and Antioch being composed largely of this cream -colored rock. A soft Tertiary limestone occurring in the vicinity of Paris has afforded a vast amount of rock, of an agreeable pale yellowish color, for fine buildings in Paris ; and a similar rock has long been used in Marseilles, Montpellier, Bordeaux, Brussels, and other places in West- ern Europe. Most limestones have been made out of comminuted shells, corals, and other like material ; and when of dark colors or black, it is usu- ally owing to some carbonaceous matters present derived from the de 4:33 DESCRIPTIONS OP ROCKS. composition of the plants or animals of the waters in which they were formed. When burnt, limestone (CaO 3 C) becomes quicklime (CaO), through loss of carbonic acid (C0 a ) ; and, at the same time, all carbonaceous materials are burnt out, and the color, when it is owing solely to these, becomes white. 2. Magnesian Limestone. Dolomyte, Carbonate of calcium and magnesium, but not distinguishable in color or texture from ordinary limestone. The amount of magnesium car- bonate afforded by analyses varies from a few per cent, to that of true dolomite (p. 55). Much of the common limestone of the United States is magnesian. That of St. Croix, Wisconsin, the " Lower Magnesian/' afforded Owen 42 '43 per cent, of magnesium carbonate. In some limestones the fossils are magnesian, while the rock is common limestone. Thus, an Orthoceras, in the Trenton limestone of Bytown, Canada (which is not magnesian), afforded T. S. Hunt, Cal- cium carbonate 56 00, magnesium carbonate 37 '80, iron carbonate 5 95 =99-75. The pale-yellow veins in the Italian black marble, called "Egyptian marble," and "portor" (see above), are dolomite, accord- ing to Hunt ; and a limestone at Dudswell, Canada, is similar. 3. Chalk. A white, earthy limestone, easily leaving a trace on a board. Composition the same as that of ordi- nary limestone. 4. Marl. A clayey or earthy deposit containing a large proportion of calcium carbonate sometimes 40 to 50 per cent. If the marl consists largely of shells or fragments of shells, it is called /Shell-marl Marl is used as a fertilizer ; and other beds of clay or sand that can be so used are often in a popular way called marl. The "Green sand " of New Jersey (p. 429) is of this kind. 5. Travertine. A massive limestone, formed by deposi- tion from calcareous springs or streams. The rock abounds on the river Anio, near Tivoli, and St. Peter's at Rome is constructed of it. The name is a corruption of Tiburtine. It occurs in the Yellowstone Park, along Gardiner's River. 6. Stalagmite. See page 216. 2. CRYSTALLINE LIMESTONE. 1. Granular or Crystalline Limestone (Marble). Limestone having a crystalline-granular texture, white to gray color, but often of reddish and other tints from impurities. It is a metamorphic rock ; it was originally common limestone ; it became crystalline under the action of more or less heat ; in KINDS OF ROCKS. 433 the process all the fossils present were obliterated, except in some cases of partial metamorphism. Its impurities are often mica or talc, trenwlite, white or gray pyroxene or scap- olite ; sometimes serpentine, through combination with which it passes into ophiolyte (p. 453) ; occasionally clion- drodite, apatite, corundum. VAKIETIES. a. Statuary marble; pure white and fine grained, b. Decorative and Architectural marble; coarse or fine, white, and mottled of various colors, and, when good, free not only from iron in the form of pyrite, but also from iron or manganese in the state of carbonate with the calcium, and also from all accessory minerals, even those not liable to alteration, and especially those of greater hardness than the marble which would interfere with the polishing, c. Verd- antique, or Ophiolyte. d. Micaceous, e. Tremolitic; contains bladed crystallizations of the white variety of hornblende called tremolite. f. Graphitic; contains graphite in iron-gray scales disseminated through it. g. Chloritic; contains disseminated scales of chlorite, h. Ghondroditic; contains disseminated chondrodite in large or smalt yellow to brown grains. White and grayish-white marble is abundant in Western New Eng- land, and Southeastern New York (Westchester County). The tex- ture is less coarsely crystalline in Vermont than in Massachusetts, the crystallization of the limestone as well as of the associated schists in- creasing in coarseness from the north to the south, or rather south- southwest, which is the trend of the limestone belt. Fine marbles are quarried in Dorset, West Rutland, Pittsford, and other places in Vermont, and the best of statuary marble occurs abundantly in Pitts- ford. The whitest marble of Rutland is not as firm as that mottled with gray, owing apparently to the fact that it was made white by the heat that crystallized it burning out any carbonaceous material ; while at Pittsford, 16 miles to the north of Rutland, it is very firm, and is white, probably, because it was made with less heat from a whiter lime- stone. In Vermont, the best quarries occur where the strata stand at a high angle : the layers in such regions were subjected to great pressure in the upturning that gave them this position, and this pres- sure has soldered many layers together in one that are separate where the pressure was less ; consequently blocks as large as an ordinary house might be obtained at some of the quarries. Good marble is also quarried in Pennsylvania, Maryland, and Tennessee. One of the most beautiful marbles from deposits of crystalline limestone in the United States, is the mottled reddish-brown from East Tennessee, and mainly from Knox and Hawkins counties. Another handsome marble is the mottled red of Burlington, Vt., from the semi-crystalline Winooski limestone ; and a still finer the deeper red (or cherry-red), mottled and veined with white, of Swan ton, Vt., from the same limestone on the northern borders of the State. The Carrara marble of Italy, the Parian, of the island of Paros (the birthplace of Phidias and Praxiteles), and the Pentelican, from quar- ries near Athens, Greece, are examples of crystalline limestone. The Carrara marble varies in quality from coarse to true statuary marble, and the best comes from Monte Crestola, and Monte Sagro. Out of 434 DESCRIPTIONS OF ROCKS. the 500 quarries only 20 furnish stone for the sculptor. The amount of marble taken out from the quarries in 1876, was 120,000 tons, valued at $2,400,000 ; and of this 40,000 tons came to the United States. The Cipoliti marbles of Italy are white, or nearly so, with shadings or zones of green talc. 2. Dolomyte. Not distinguishable by the eye from gran- ular limestone. Part of the marbles above referred to are dolomyte. This is the case with that of Westchester County, N Y. , that of Canaan, Con- necticut, and of Lee and Stockbridge, Massachusetts. II. Crystalline Rocks, exclusive of Limestones. The crystalline rocks may be distributed according to their composition into the following series or groups. Each, excepting the first, embraces both metamorphic and eruptive rocks. 1. Siliceous rocks. The kinds consisting mainly of quartz or opal are here included. The first of those mentioned, page 435, is intermediate between the f ragmen tal and meta- morphic-crystalline rocks. The opal material is a chemical deposit. The chert of sedimentary formations is believed to be mainly tripolite consolidated through the solution of a part of its material by the permeating waters and its sub- sequent desposition tripolite or diatom beds being made chiefly of opal-silica which is readily soluble in waters slightly alkaline. 2. The Mica and Potash-Feldspar series. These are emi- nently alkali-yielding rocks, both the mica, whether mus- covite, biotite, or lepidomelane, and the feldspar, whether orthoclase or microcline, affording on analysis, as explained on page 411, much potash, and the feldspars often also some soda. The soda feldspar, albite or oligoclase, is a common accessory ingredient. The series shades off into a rock that is chiefly feldspar, and another that is chiefly mica ; and in these two extremes the amount of potash yielded is about the same. Moreover, as leucite is essentially a potash- feldspar in ratio and composition (see page 411), rocks, con- sisting chiefly of leucite, without pyroxene or hornblende, belong with this series. Muscovite and biotite commonly occur together, the formation of biotite having been deter- mined by the presence of some iron oxide in the original material from which it was made. The mica is sometimes a hydrous species (page 313). KINDS OF ROCKS. 3. The Mica and Soda-lime-Feldspar series. These grani- toid rocks are equally alkali-yielding with those of the true granite group, but the alkali is mainly soda. The nephelite (elseolite) rocks not hornblendic are here included, although they contain in general some microline or orthoclase. 4. The Hornblende and Potash-Feldspar series, or the Sye- nyte group. In this series, the mica of the granite series is replaced by the non-alkaline mineral, hornblende. Transi- tions between the granite and syenyte rocks are common a bed that is true mica schist often becoming hornblendic ; the same specimen may have mica and hornblende crystals together, or parallel mica and hornblende layers, and then, not far beyond the schist may be a purely hornblende rock ; and so there are similar transitions in other parts of the two series. This transition in a stratum of mica schist, a metamorphic rock, indicates merely that the mud-bed or sedimentary stratum, out of which the mica schist \^as made, had a diminished proportion of alkali in some parts, and, in still others, a complete absence of alkali which is just such a variation as might be looked for in oceanic sedi- ments, as they spread over a wide region. The hornblende may be replaced by epidote, another iron-bearing mineral. 5. The Hornblende and Soda-lime-Feldspar series. The soda-lime-feldspars, in this series, may be either of the triclinic species, from albite to anorthite. 6. The Pyroxene and Soda-lime-Feldspar series. The soda- lime-feldspars are the same as in the preceding. Quartz is very rarely present, except in traces. Potash replaces soda in amphigenyte. 7. Pyroxene, Garnet, Epidote and Chrysolite rocks, con- taining little or no Feldspar. 8. Hydrous Magnesian and Aluminous rocks, &. Iron Ore rocks 1. SILICEOUS ROCKS. 1. Quartzyte, Granular Quartz. A siliceous sandstone, usually very firm, occurring in regions of metamorphic rocks. It does not differ essentially from the harder sili- ceous sandstones of other regions. Conglomerate beds are sometimes included. VARIETIES. a. Massive, b. Schistose, c. Calcareous; sometimes contains disseminated calcite which, where the rock is exposed to weathering, is removed and leaves the rock loose in texture, or cellu- 436 DESCRIPTIONS OF ROCKS. lar. d. Micaceous, e. Hydromicaceous ; it graduating at times into hydromica or mica slate, f. Feldspathic, sometimes porpJiyritic (the rock Arkose), or like granulite in its disseminated feldspar ; a coarsely f eldspathic variety occurs north of Lenox, Mass. , and when it loses its feldspar, it becomes cellular, like buhrstone ; at other places, as in Cheshire, Savoy, and eastern Washington, Mass., the feldspar of a feebly-consolidated quartzyte has been leached out by the tiltrating waters, and the rock reduced thereby to sand, excellent for glass-mak- ing, while in some localities the feldspar so removed has been made into valuable beds of white kaolin, as in Brandon, Vermont, East Shef- field, Mass., and elsewhere, g. Gneissoid ; containing some mica and feldspar in layers, and so graduating toward gneiss, h. Andalu- sitic ; containing andalusite, as in Mt. Kearsarge (Hitchcock), i. Tour- malinic ; containing tourmaline. The vicinity of the great crystalline limestone formation of the Green Mountain region, in Western New England (in Vermont to the west of the principal ridge of the Green Mountains), includes strata of quartzyts of great thickness, and high summits in Bennington, and to the north, and also south, consist of it. In several places the quartzyte strata graduate into, and also alternate with, hydromica or mica slates, and in Massachusetts and Connecticut, with gneiss. Between Bernardston, Mass., and Vernon, Vt., quartzyte occurs in large beds, and also graduates into gneiss and hornblendic rocks. Quartzyte exists also in the central part of the Southern New Hampshire, in the Archaean area of Wisconsin, and in the Rocky Mountain region, j. NovacuUtic-quartzyte, or Novaculyie (Whetstone). Novaculyte is only in part an extremely fine-grained siliceous rock. Of this nature is the variety from Whetstone or Hot Spring Ridge, in Arkansas. This ridge, 250 feet in height above the Hot Spring Valley, is made up of the beautiful rock, "equal," says D. D. Owen, "in whiteness, closeness of texture, and subdued waxy lustre, to the most compact forms and whitest varieties of Carrara marble. Yet it belongs to the age of the millstone grit." Dr. Owen supposed it to have re- ceived its impalpable fineness through the action of the hot waters on sandstone. An analysis of the rock afforded him (Second Rep. Geol. Arkansas, 1860, p. 24), Silica 98'0, alumina 0'8, potash 0'6, soda 05, moisture, with traces of lime, magnesia and fluorine O'l = 100. He states that alon^ the southern flank of the ridge there are over forty hot springs, having a temperature of 100 F. to 148 F. Solid masses from the fine rock have been got out weighing about 1,200 Ibs. ; the coarser varieties are made into stones for bench tools. Beds of quartzyte have been made, like those of sandstone, out of the quartz grains of older rocks, no evidence, chemical or geological, favor- ing the view that they could be, or have been, produced by chemical deposition. Some quartzytes and sandstones have had part of the grains converted into more or less perfect quartz crystals, from the de- position about them of silica in the process of consolidation the little heat required for making the siliceous waters coming from the earth's interior, as a consequence of thick accumulations of strata above, or from the friction of upturning, or from warm springs. 2. Itaeolumyte. Schistose, consisting of quartz grains with some hydrous mica ; on account of the mica in the lamina- tion, it is sometimes flexible, and is called flexible sandstone. KINDS OF ROCKS* 437 Occurs in the gold regions of North Carolina and Brazil, and diamonds are supposed to be sometimes connected as to origin with this rock. 3. Siliceous Slate. Schistose, flinty, not distinctly granu- lar in texture. Sometimes passes into mica slate or schist. 4. Chert. An impure flint or hornstone occurring in beds or nodules in some stratified rocks. It often resem- bles fclsyte, but is infusible. Colors various. Sometimes oolitic. Kinds containing iron oxide graduate into jasper and clay ironstone ; and others, occurring as layers or no- dules in limestone are whitish, owing to the limestone material they contain. Chert sometimes contains cavities which are lined with chalcedony or agate, or with quartz crystals. 5. Jasper rock. A flinty siliceous rock, of dull red, yel- low, or green color, or some other dark shade, breaking with a smooth surface like flint. It consists of quartz, with more or less clay and iron oxide. The red contains the oxide in an anhydrous state, the yellow in a hydrous ; on heating the latter it turns red. 6. Buhrstone. A cellular siliceous rock, flinty in texture. Found mostly in connection with Tertiary rocks, and formed apparently from the action of siliceous solutions on preexisting fossil'iferous beds, the solutions removing the fossils and leaving cavities. Buhrstone is the material preferred for millstones. The buhrstone of the vicinity of Paris, France, has long been largely exported for this purpose. Good buhrstone is obtained also from the Tertiary in Greenville District, South Carolina, 100 miles up the Savannah River. 7. Fioryte. (Siliceous Sinter, Pearl Sinter, Geyserite.) Opal-silica, in compact, porous, or concretionary forms, often pearly in lustre ; made by deposition from hot sili- ceous waters, as about geysers (Geyserite), or through the decomposition of siliceous minerals, especially about the f umaroles of volcanic regions. Geyserite is abundant in Yellowstone Park, and about the Iceland geysers ; after long exposure it crumbles down and becomes changed to ordinary silica, or quartz. 2. MICA AND POTASH-FELDSPAR SERIES. 1. Granite. Consists of quartz, orthoclase, and mica, and has no appearance of layers in the arrangement of the mica or other ingredients. G. = 2'5-2'8. The quartz is usually grayish-white or smoky, glassy, and without any appearance 438 DESCRIPTIONS OF ROCKS. of cleavage. The feldspar is commonly whitish or flesh- colored, and may be distinguished from the quartz by its cleavage surfaces, which reflect light brilliantly when the specimen is held in the sunlight. The mica is usually in small bright scales, either silvery, brownish-black, or black in color, and the point of a knife carefully used will easily split them into thinner scales ; the silvery mica is muscovite, but sometimes of the allied hydrous kinds, margarodite or damourite, and the black mica is usually biotite, though occasionally the allied, more iron-bearing, species, lepidome- lane. Oligoclase or albite is very often present. Occurs both metamorphic and eruptive. Metamorphic granite may often be seen graduating into gneiss, or lying in beds alternating with gneiss. VARIETIES. There are, A. Muscovite granites ; B. Biotite granites ; C. Muscovite-and-biotite granites, the last much the most common. The most of the following varieties occur under each except the horn- blendic, which is usually a Biotite, or Muscovite-and-Biotite, granite. There is also, D. Hydromica-granite. a. Common or Ordinary granite ; the color is grayish or flesh-colored, according as the feldspar is white or reddish, and dark gray when much black mica is present. Granite varies in texture from fine and even, to coarse ; and sometimes the mica, feldspar, and quartz especially the two former are in large crystalline masses. An average granite (mean of 11 analyses of Lein- ster granite, by Haughton) affords Silica 72*07, alumina 14'81, iron protoxide and sesquioxide 2'52, lime 1*63, magnesia 0'33, potash 5'11, soda 2-79, water 1-09=100-35. b. Porphyritic granite; has the ortho- clase in defined crystals, and may be (a) small porphyritic, or (ft) large porphyritic, and have the base (y) coarse granular, or (6) fine, and even subaphanitic. c. Albitic granite; contains some albite, which is usually white, d. Oligoclase granite (Miarolite) ; contains much oligo- clase. e. Microcline granite ; contains the potash triclinic feldspar, microcline. f. Hornblendic granite; contains black or greenish-black hornblende, along with the other constituents of granite, g. Black micaceous granite ; consists largely of mica, with defined crystals of feldspar (porphyritic), and but little quartz, h. lolitic ; con- taining iolite. i. Globuliferous granite; contains concretions which consist of mica, or of feldspar and mica. j. Oneissoid granite; a granite in which there are traces of stratification; graduates into gneiss, k. Pegmatyte, or Graphic granite ; consists mainly of ortho* clase and quartz, with but little mica ; but the quartz is distributed through the feldspar in forms looking like oriental characters. A porphyritic granite, occurring at the junction of the andalusite mica-argillyte (page 441) of the White Mountain Notch, N. H., with the Mt. Willard granite, on the west side of Mt. Willard, conformable with the bedding of the argillyte, has the argillyte for its base ; and in it the orthoclase is in large well-defined crystals, and the quartz in double six-sided pyramids, both easily separable from the matrix ; the layer is six to twenty feet thick. KINDS OF ROCK. 439 The distinctions as to kinds of rocks between metamorphic and eruptive granites are not yet made out. A porphyritic variety, having the base fine-grained, occurs east of Parkview Peak, in the Rocky Mts., which, according to Hague, is eruptive and related to the trachytes of the region. The granite of New England is for the most part meta- morphic or in veins. The following are prominent regions of the granite quarries. In Maine : at Hallo well, a whitish granite, some- times a little gneissoid ; at Rockport, whitish ; at Clarke's Island, spotted gray ; at Jonesbury, flesh-red ; also in the Mt. Desert region! In New Hampshire, at various places, but most prominently near Con- cord, a fine-grained whitish granite. In Massachusetts at several points, especially in Gloucester at Rockport, a red granite. (The Quincy "granite" is a syenyte.) In Rhode Island, at Westerly, a fine-grained whitish granite. In Connecticut, at Millstone Point near Niantic, and at Groton, near New London, a fine-grained whitish granite ; at Stoney Creek, a pale reddish, but liable to large micaceous spots ; at Ply- mouth, on the Naugatuck, a whitish granite, even and fine-grained, more easily worked than the Westerly. 2. Granulyte. (Leptinyte.) Like granite, but containing no mica, or only traces. Metamorphic and eruptive. VABIETIES. a. Common granulyte ; white and usually fine granu- lar, a common rock in Western Connecticut and West Chester Co., New York. b. Flesh-colored; usually coarsely crystalline, granular, and flesh-colored; the coarse flesh- colored "granite" of the Eastern or Front Range of the Rocky Mts. , in Colorado, sometimes called Aplite, is partly of this kind ; it contains a little albite or oligoclase with the orthoclase. c. Garnetiferous. d. Hornblendic ; containing a little hornblende a variety that graduates into syenyte. e. Magnctitic ; containing disseminated grains of magnetite, a kind common in Archaean regions, in the vicinity of the iron ore beds, occurring in Orange Co., N. Y., and south in New Jersey, and also at Brewster's, Dutchess Co., N. Y., and in Kent and Cornwall, Conn. f. Graphic (Pegmatyte) ; like gr. A jhic granite, but containing no mica. The coarser granulyte, especially that of veins, is often called pegmatyte when not graphic. 3. Gneiss. Like granite, but with the mica and other ingredients more or less distinctly in layers. Gneiss breaks most readily in the direction of the mica layers, and hence its schistose structure ; in consequence of this structure, many kinds may be got out in slabs. It often graduates imperceptibly into granite. Metamorphic. VARIETIES. Similar to those under granite, a. Porpliyritic. b Al- Utic c Oligodase-bearing. d. Hornblendic. e. Micaceous, f. Crloou- UProiis. g. Epidotic. h. Garnetiferous. i. Andalusitic; contains an- dalusite in disseminated crystals, j. Cyanitic ; contains cyanite, a variety that has been observed on New York Island, and also in New, town Ct. Bellows Falls and elsewhere in N. H. k. Graphitic; con- tains graphite disseminated through it. 1. Quartzose ; the quartz largely in excess, m. Quartzytic ; consists largely of quartz in grams, being intermediate between quartzyte and gneiss, a variety occurring just northeast of Bernardstou, Mass. Fig. 3 on page 415 represents, 440 DESCRIPTIONS OF ROCKS. natural size, a small pioce of the porphyritic gneiss of Birmingham, Conn. Some gneiss is very little schistose, being in thick, heavy beds, granite-like, while other kinds, especially those containing much mica, are thin-bedded, and very schistose ; the latter graduate into mica schist. The so-called granite of Monson, Mass., is a granitoid gneiss. Its gneissoid structure facilitates greatly the quarrying. 4. Protogine. Protogiae-gneiss. Coarse to fine granular, granite-like or gneissoid in structure, and mostly the lat- ter ; of a grayish-white to greenish-gray color ; consists of quartz, white or grayish- white, rarely flesh-red, orthoclase, a dark green mica and often chlorite, with some greenish- white talc, and white oligoclase. Metamorphic. The dark green mica approaches chlorite, as shown by Delesse, in its very large percentage of iron oxide (Fe 2 3 21'31, FeO5 03), but it gave him only 90 of water, with 6 '05 of potash. Among accessory minerals are hornblende, titanite, garnet, serpentine, magnetite. In an analysis of the protogine as a whole, Delesse obtained Silica 74-25, alumina 11'58, iron oxide 2'41, lime 1'OS, water 0-97, leaving 10*01 for potash, soda and magnesia. From the region of Mont Blanc and other parts of the Swiss Alps. 5. Mica Schist. Consists largely of mica, with usually much quartz, some feldspar, and, on account of the mifti, divides easily into slahs, that is, is very schistose. Usually both of the potash micas, muscovite and biotite, are present, and the latter (black mica) is commonly much the most abundant. The colors vary from silvery to black, according to the mica present. Often crumbles easily; and roadsides are sometimes spangled with the mica scales. The dissemi- nated scales or crystals of biotite are sometimes set trans- versely to the bedding. Metamorphic. VARIETIES. a. Gneissoid ; between mica schist and gneiss, and containing much feldspar, the two rocks shading into one another. b. Hornblendic. c. Garnetiferous. d. Staurolitic. e. Cyanitic. f. An- dalusitic. g. Fibrolitic ; containing fibrolite. h. Tourmalinic. i. Cal- careous ; limestone occurring in it in occasional beds or masses. j. Graphitic, or Plumbaginous ; the graphite being either in scales or impregnating generally the schist, k. Quartzose; consisting largely of quartz. 1. Quartzytic ; a quartzyte with more or less mica, rendering it schistose, m. Specular, or ltdbyrite ; containing much hematite or specular iron in bright metallic lamellae or scales. In fine-grained mica schist, the scales of mica tire sometimes scarcely visible without a lens. 6. Hydro-mica Schist. A thin-schistose rock, consisting either chiefly of hydrous mica, or of this mica with more or less quartz. ; having the surface nearly smooth, and KINDS OF ROCKS. 441 feeling greasy to the fingers ; pearly to faintly glistening in lustre ; whitish, grayish, pale greenish in color, and also of darker shades. For analyses of hydrous micas see page 313. Metamorphic. This rock used to be called talcose slate, but, as first shown by Dr. C. Dewey, it contains no talc. It includes Parophite schist, Damourite slate and Sericite slate (Glanz-Schiefer and Sericit-Schiefer of the Ger- mans.) VARIETIES. a. Ordinary ; more or less silvery in lustre, b. Chlo- ritic ; contains chlorite, or is mixed with chlorite slate, and has there- fore spots of olive-green color; graduates into chlorite slate, c. Gar- netiferous. d. Pyritifcrous ; contains pyrite in disseminated grains or crystals, e. Mugnetitie ; contains disseminated magnetite, f . Quart- zytic; consists largely of quartzyte, or is a quartzyte rendered schistose and partly pearly by the presence of hydrous mica, as is well seen in a ridge northeast of Rutland, Vermont, which consists partly of quartzyte and partly of hydromica schist. 7. Paragonite Schist. Consists largely of the hydrous soda mica called paragonite (p. 314); but in other characters resembles hydromica schist. Metamorphic. 8. Minette. Brown to black, fine-grained, compact, not distinctly schistose ; consisting of biotite (according to the description and analysis of Delesse) and orthoclase ; contains also a little hornblende. Occurs in beds in the Vosges, France, associated with granite, syenytc, and other crystalline rocks. Sometimes feebly porphyritic and small- concretionary, the concretions consisting mainly of ortho- clase. Made eruptive by Delesse, and metamorphic by some later authors. Approaches argillyte in aspect. 9. Greisen. Massive, without schistose structure. A mix- ture of granular quartz and mica, in scales. The mica may be muscovite, lepidolite, or biotite. It is a granite with the feldspar left out, and occurs in regions of gneiss, granite, or quartz vte, and sometimes graduates into these rocks. Metamorphic. Occurs in characteristic form at Zinnwald, in the Erzgebirge, where it sometimes contains tin ore as an accessory ingredient, and is fre- quently penetrated by veins of tin ; also in the tin ore regions of Schlackenwald and Cornwall. Occurs in the region of quartzyte, horn- blendic rocks and gneiss, of Upper Silurian age, between Bernards- ton, Mass , and Vernon, Vt., within three miles northeast of the former place, and also near Vernon ; but at this place it contains usually a little hornblende, making it a very tough rock, and is intermediate between the quartzyte, homblendic rock and mica schist of the region. 10. Mica- Argillyte or Mica-Phyllyte. Includes the part of argillyte (p. 428) which has the composition nearly of a hy- drous mica, like that of the White Mountain Notch, where 442 DESCRIPTIONS OF ROCKS. much of it is andalusitic. Analysis of this White Mountain rock, by Hawes, afforded Silica 46*01, alumina 30'56, iron sesquioxide 1*44, iron protoxide 6*85, manganese protoxide 0*10, magnesia 1*42, soda 1*12, potash 6 '66, titanium dioxide 1*91, water 4*13 = 100-22. (Compare with analyses of hy- drous muscovite, or margarodite.) Metamorphic. 11. Felsyte. Quartz-Felsyte. (Euryte, Petrosilex.) Com- pact orthoclase, with often some quartz intimately mixed; fine granular to flint-like in fracture; sometimes contains oligoclase. Colors white, grayish-white, red, brownish-red to black. G.^2'6-2'7. Both metamorphic and eruptive. VAEIETIES. There are two sections, I. Felsyte, and II. Quartz- Felsyte, and under each occur the following varieties, a. Porphyritic FeUyte, or Porphyry ; containing the feldspar in small crystals distri- buted through the compact base ; color red and of other shades ; called sometimes Quartz-porphyry, when the base is a quartz-felsyte. b. Con- glomerate fclsyte ; containing pebbles, as at Marblehead, Mass., and in the White Mountains, c. OUyoclase-bearing ; containing this triclinic feldspar intimately blended with the orthoclase. d. Cellular or amyg- daloidal. e. Elvanyte ; essentially a quartzose felsyte, of gray, bluish- gray to brown and red colors, and often containing disseminated grains or crystals of quarfcz and feldspar, and some oligoclase ; some compact slate-rock has the sams composition. Occurs in Cornwall. The metamorphic and eruptive kinds are not easily distinguished. The former occurs associated with sedimentary strata, and often con- tains pebbles or other evidence of fragmental origin ; while the lat- ter is frequently in dikes, that is, fills the fissures through which it was ejected. Some of the eruptive felsyte has nearly the aspect of trachyte, with which rock it is identical in composition. Much of the red porphyry contains hornblende with the feldspar of the base, and has the constitution of dioryte (p. 447). 12. Porcelanyte. (Porcelain Jasper.) A baked clay, hav- ing the fracture of flint, and a gray to red color; it is some- what fusible before the blowpipe, and thus differs from jasper. Formed by the baking of clay-beds, when they con- sist largely of feldspar. Such clay-beds are sometimes baked to a distance of thirty or forty rods from a trap dike, and over large surfaces by burning coal beds. Metamorphic. 13. Trachyte. Quartz-Trachyte. Consists mainly of feld- spar, which is partly in glassy crystals, either sanidin or oligoclase ; and, owing to the angular forms of the glassy feldspar and the porosity of the rock, the surface of frac- ture is rough, whence the name from the Greek trachus, rough. Sometimes contains disseminated quartz, and is then quartz-trachyte. Color ash-gray, greenish-gray, brown- ish-gray, but sometimes yellowish and reddish. G. =2'5- 2*7. Besides the feldspar there are distributed, somewhat KINDS OF ROCKS. 443 sparingly, through the mass, in many kinds, minute needles of hornblende, crystals or scales of biotite, magnetite ; some- times nephelite, haiiynite, tridymite. Apatite exists in the rock in microscopic forms, and there is also more or less of the rock in a glassy state. Sometimes contains augite, and has a higher specific gravity. Quartz-trachyte has often nearly the composition of granite in which there is little mica. Eruptive only. VARIETIES. The two principal divisions under each, trachyte and quartz-trachyte, are : A. Kanidin-trachyte, in which the mass is chiefly sanidin ; and B. Oliyodasc-trachyte, or Domyte, in which it is partly oligoclase ; but the two graduate into one another. Both occur por- pliyritic with tabular crystals of feldspar ; and in the latter (as at the Drachenfels) the tables are sanidin. They graduate into vesicular or scoriaceous trachyte. Trachyte, according to Reyer and Suess, occurs in the region of the Euganean Hills of Tertiary, Cretaceous and Jurassic age ; and the f elsyte of Paleozoic age is often hardly distinguishable from it, while identical with it in composition. Trachyte and quartz-trachyte, graduate also into felsyte-like volcanic rocks of like constitution, porphyritic or not so. The latter sometimes shades into rocks of semi-glassy nature called 14. Pearlstone, when somewhat pearly in lustre; PITCHSTOXE when having a pitch-like lustre; and these into the glassy volcanic material called Obsidian. These glassy rocks often contain spherules which are concretions consisting of feld- spar with some quartz. Pumice is a light, porous, feldspa- thic scoria, with the pores capillary and parallel. Ordina- ry obsidian, that consists chiefly of feldspar, and is hence nearly free from iron, belongs here; the rest of it belonging with the augitic igneous rocks. 15. Leucityte. A grayish rock consisting chiefly of leucite in a felsitic state, with disseminated leucite crystals. Occurs at Point of Rocks, Wyoming Territory, according to King and Zirkel. It differs" from amphigenyte, in containing no pyroxene, or only traces of it. 3. MICA AND SODA-LIME-FELDSPAR ROCKS. I. NOT CONTAINING NEPHELITE. 1. Hemi-dioryte. (Mica-dioryte, Soda-granite.) A gran- ite-like rock, in which the feldspar is chiefly oligoclase ; it contains much biotite, with usually some quartz, and often some hornblende. Occurs at Stony Point, on the Hudson, 444 DESCRIPTIONS OF ROCKS. and near Cruger's, in the town of Cortland, N. Y., at the latter place often graduating into a granite-like dioryte. Kersantyte is described by Delesse as consisting of biotite and oligo- clase, with some quartz, frequently hornblende in needles, and mag- netite ; from the Vosges, the Saxon Erzgebirge, and Nassau. Kersan- ion is a similar rock, containing no hornblende, from near Brest, and from Quimper, in Brittany. Both of these rocks have been called mica- dioryte. Kinzigyte^ is a compact and schistose granular-crystalline rock, con- sisting of biotite, oligoclase, and garnet, without quartz, and contain- ing, as accessory, microcline, iolite and fibrolite ; from Kinzig, north part of Black Forest. II. CONTAINING NEPHELITE. 1. Miascyte. Granitoid to schistose, and consisting of microcline, massive nephelite (elaeolite), sodalite, biotite, along with some quartz, and often some zircon, pyrochlore, monazite and other minerals. A related nephelite rock oc- curs on Pic Island, Lake Superior. Named by G. Rose, from Miask in the Ilmen Mountains, where it has a wide distribution. Metamorphic. 2. Ditroyte. A coarse to fine-grained rock, consisting of microcline, nephelite (elasolite), and sodalite. From Ditro in Eastern Transylvania, where it is associated with syenyte and mica schist and lies between these two rocks. 3. Phonolyte. (Clinkstone.) Compact; of grayish, blue, and other shades of color ; more or less schistose or slaty in structure; tough, and usually clinking under the hammer, like metal, when struck, whence the name. G.=2vk-2'7. Consists of glassy feldspar (orthoclase or oligoclase), with nephelite and some hornblende. G. Jenzsch gives, for the composition of the Bohemian phonolyte, Sanidin (glassy or- thoclase) 53-55, nephelite 3T76, hornblende 9-34, sphene 3-67, pyrite 0-04=98*36. Under treatment with acids the nephe- lite is dissolved out. Nosean and hauynite occur in some phonolyte. Eruptive only. 4. HORNBLENDE AND POTASH-FELDSPAR SERIES. In this series the hornblende is sometimes replaced by epidote, another anhydrous iron-bearing mineral, yielding on analysis little or 110 alkali ; microcline is often present as well as orthoclase. The species graduate into kinds con- sisting almost solely of hornblende. Biotite is often pres- ent as an accessory mineral. KINDS OF ROCKS. 445 I. NOT CONTAINING NEPHELITE. 1. Syenyte. Quartz-Syenyte, A granitoid rock consisting of hornblende and orthoclase, with or without quartz. Oligo- clase and biotite are often present. The quartziferous va- riety, or qudrtz-syenyte, includes the syenyte of the obe- lisks and pyramids of Egypt. Like that, the rock is often flesh-colored ; but whitish and grayish varieties are also common. The Saxon syenyte, without quartz, afforded Silica 59*83, alumina 16*85, iron protoxide 7*01, lime 4*43, magnesia 2'61, potash 6*57, soda 2*44, water 1*29, and Gr. = 2- 75-2 -90. Metamorphic and eruptive. Similar varieties occur under both divisions of syenyte. VAEIETIES. a. Porphyritic. b. AlUtic ; containing albite in addi- tion to the constituents of true syenyte. c. Oligodase-bcaring. d. Mi- caceous ; containing disseminated black mica, which is usually bio- tite, and sometimes lepidomelane. e. Garnetiferous. f. Epidotic / containing disseminated epidote. The gray " granite " of Quincy, Massachusetts, south of Boston, extensively quarried for architectural piirposes, is a quartz-syenyte, consisting of orthoclase, black to dark green hornblende, and quartz, with some triclinic feldspar. Quartz- syenyte occurs also in the Frankenstein Cliff, five miles south of White Mountain Notch ; also in Mount Chocorua, N. H. ; in the Ar- chaean of Canada, at Grenville, a red kind containing very little quartz, and a similar rock on Barrow Island, St. Lawrence, but containing much quartz and little hornblende. Syenyte without quartz is a rare rock in Eastern North America. It occurs in Nevada. The name Syenites is used for this rock by Pliny, who adds that it was also called " pyrrhopoecilon" this appellation, meaning fire-red variegated, referring to its being brightly spotted with rose-red. The quarries in the vicinity of Syene (the modern Assouan), whence the Egyptians obtained this stone for their obelisks, columns, statues, sphinxes, sarcophagi, and the lining of their pyramids, are of great extent ; and in one of them there is an unfinished obelisk in its origi- nal position. They are situated to the south of Syene, and between that place and the island of Philoe. The rock consists chiefly of red feldspar and grayish quartz, with oligoclase, some black hornblende, and a little black mica. An analysis by Delesse obtained Silica 70 '25, alumina 16 00, iron oxide with some manganese 2 '50, lime 1'GO, expelled on ignition 4'65, magnesia and alkalies by loss 9 00=100. More remote from Syene the rock loses its hornblende and becomes a granite. The Scotch syenyte, so much used for monuments, is quartz-syenyte. It occurs both red and dark gray, and the former is closely like the Egyptian syenyte. Werner applied the name " syenyte " to the quartzless syenyte of Plauen.schen- Grunde, Saxony, an analysis of which is given above (a rock he afterwards called "greenstone"). G. Rose used the term for the quartz-syenyte. Other German lithologists have followed Werner, calling the quartz-syenyte, hornblende-granite. It seems best to draw 446 DESCRIPTIONS OF ROCKS. the line between the mica-bearing and the hornblende-bearing rocks, as here done, and to use the name syenyte for the rock to which it was originally applied, as well as for the quartzless kinds. 2. Syenyte-gneiss. Like gneiss in aspect and schistose structure ; and also in constitution, except that horn- blende replaces mica. Occurs both with and without quartz, though usually quartz-bearing. The varieties are nearly the same as under syenyte. Metamorphic. 3. Hornblende schist. A schistose rock consisting of horn- blende, with usually more or less quartz, but sometimes almost wholly hornblende. Frequently contains epidote, garnet, magnetite. Metamorphic. 4. Amphibolyte or Hornblendyte, A tough, granular-crys- talline rock, consisting of hornblende, and hardly schistose in structure. Color, greenish-black to black. Metamorphic. A Glaucophanitic. variety consists chiefly of the blue soda-hornblende, called glaucophane, with usually some black mica ; from Saxony, Isle of Syra, New Caledonia. A cTirysolitic variety occurs at Stony Point, Rockland Co., N. Y., and on the opposite side of the Hudson River, north of Cruger's. 5. Actinolyte. A tough, massive rock made chiefly of actinolite. Grayish green. Metamorphic. 6. Unakyte. A flesh-colored granitoid rock consisting of orthoclase, quartz, and much yellowish-green epidote. From the Unaka Mountains, North Carolina, and East Tennessee. II. CONTAINING NEPHELITE. 1. Zircon-Syenyte. A crystalline granular rock consisting of orthoclase, microcline, little hornblende, crystals of zir- con, and some elseolite. 2. Foyayte. Coarse crystalline, granular to compact ; consists of orthoclase, reddish-brown nephelite (eloeolite), in six-sided prisms, and blackish-green hornblende. Occurs alsoporphyritic, and passes into an aphanitic variety. From Mt. Foya and Picota, in the Province Algarve, in Portugal. Ditroyte (p. 444) is related, but contains very little horn- blende. 5. HORNBLENDE AND SODA-LIME-FELDSPAR SERIES. I. NOT CONTAINING SAUSSURITE IN PLACE OF THE FELDSPAR CONSTITUENTS. 1. Dioryte. Quartz-Dioryte. ( Greenstone in part. ) The triclinic feldspar, one of the acidic (rich in silica) species, KINDS OF HOCKS. 447 albite or oligoclase. Texture granitoid to fine-grained or compact. Color often grayish-white to greenish-white for the coarser kinds ; olive-green to blackish-green for the finer. Very tongh. G. =2-7-3 '0. The quartz-bearing and quartz-less kinds constitute two sections having similar va- rieties. Dark-red, brownish-red, and dark-green porphy ritic kinds, compact in base, have been called porpliyryte. Metamorphic and eruptive. VARIETIES. a. Granitoid; granite-like in texture, b. Compact or fine-grained, with the feldspar grains scarcely distinguishable. c. Porphyritic ; the feldspar in crystals in a compact base. d. Slaty ; a dioryte slate or schist, usually chloritic. e. Micaceous, f. Apha- nitic (or Aphanite) ; nearly flint-like in texture. An analysis of a dioryte of the Hartz afforded Silica 54'65, alumina 15 "72, iron sesquioxide 2 '00, iron protoxide 6 '26, manganese protoxide trace, magnesia 5 '91, lime 7'83, potash 3'79, soda2'90, water and ig- nition 1-90 = 100-96. The antique red porphyry, or "rosso antico," figured on page 415, is an example of porphyritic dioryte. The crystals, according to the analysis of Delesse, are oligoclase, and have G. =2'67, while the base has G.=2'765, it consisting of an intimate mixture of oligoclase and hornblende, with some grains of iron oxide. For the whole mass, accord- ing to Delesse, G. =2.703, but after fusion, only 2 '486. Distinct acicu- lar crystals of hornblende occur in it. The rock is sometimes a brec- cia, being made up of angular fragments, either quite distinct from the mass or else shading off into it, but all alike porphyritic. The Mt. Dokhan, in which it occurs " Porphyrites mons" of Ptolemy con- tains also red syenyte similar to that of Syene, and a coarse red gran- ite. The "porphyrite" of Ilfeld, of Schonau in Bohemia, and the " quartz -porphy rite" of Koliwansk in the Altai are here referred. Propylyte and quartz-propylyte have 'the same constitution. The former is the prevailing igneous rock of the Washoe district (vicinity of the Comstock lode), in Nevada ; it is a grayish-green rock, yield- ing, on analysis, 64 to 66 per cent, of silica, and containing, along with oligoclase, hornblende, disseminated in minute points, and rarely alsobiotite (Zirkel). Ophite, of the Pyrenees, is greenish black dioryte. 2. Andesyte. Quartz- Andesyte. Contains the feldspar an- desite along with hornblende. As in the preceding, the hornblende' is sometimes changed to chlorite. Quartz-an- desyte, or Dacyte, is a quartz-bearing variety. Both kinds occur in the Washoe district, Eruptive. Also metamorphie? Banatite and Tonalite are like quartz-dioryte in most characters, but have the feldspar the species andesite. Each contains some bio- tite, the latter much of it. Banatite is from the Banat, and Tonalite from near Tonal e, in the Southern Alps. Trachydoleryte (of Abich\ a dark gray to reddish-brown rock, some- what trachyte-like in aspect, is, in part, near andesyte, it consisting of 448 DESCRIPTIONS OF HOCKS. oligoclase or andesite and hornblende, with G. 2 73 2*80, and afford- ing 55 to 01 per cent, of silica ; it occurs in the Peak of Teneriffe, on Liscanera I. near Stromboli, and on some parts of Etna. Another rock included under this name, found at Stromboli, Rocca Monfina, and Tunguragua in Quito, contains augite in place of hornblende, with oligoclase or labradorite, and is near doleryte. A third rock described under this name by Ludwig is augitic trachyte, the feldspar being sanidin. Trachyte graduates into andesyte, augite -andesyte, doleryte, as well as granite. 3. Labradioryte. (Labradorite-Dioryte, Greenstone in part.) The feldspar one of the basic (poor in silica) species, la- bradorite or anorthite. Texture usually fine-grained, some- times crypto-crystalline. Color light grayish-green to dark olive-green, blackish-green or gray, and sometimes black. Very tough. G. =2 -8-3*1. Often contains chlorite and magnetite. Often has associated with it beds of serpentine or ophiolyte. Metamorphic and eruptive. VABIETIES. a. Granular crystalline, b. Compact, or fine-grained ; of dark green color ; constituent minerals not distinct, c. Porphyri- tic ; the feldspar in whitish or greenish- white crystals disseminated through a fine-grained bass, making a greenish "porphyry;" its crystals sometimes anorthite. d. Pyroxcnic ; containing some dissem- inated pyroxene, e. Magnetitic ; containing magnetite or titanic iron. Occurs in the Urals ; to the west of New Haven, Conn., both massive and porphyritic ; in Littleton, N. H. A porphyritic variety of the rock near New Baven a metamorphic rock afforded Hawes, Silica pact non-porphyritic variety from the same formation, collected on Stoeckel's farm, afforded Hawes, Silica 50'36, alumina 14'57, iron ses^ quioxide 2'48, iron protoxide 8'31, manganese protoxide 0'46, magne- sia 7-62, lime 11-13, soda 3'04, potash 44, water 0'78, titanium diox- ide 1'70, chromium oxide 0'78 100*89 ; G.=3'04. The crystals of the porphyritic variety, according to an imperfect analysis by E. S. Dana, consist of anorthite. 4. Corsyte. A granitoid rock, consisting chiefly of anor- thite and hornblende, with some quartz and biotite. From Corsica. Teschenite is bluish-green, and chiefly consists of anor- thite, hornblende, and augite, the hornble de sometimes in large black prisms ; also contains analcite. From Teschen, Austria. 5. Isenite. Contains a triclinic feldspar and hornblende, with much nephelite and nosean, and some magnetite. From the Eisbach (Isena) district in the Westerwafd, West Germany. KINDS OF ROCKS. 449 II. SAUSSURITE-BEARING. 6. Euphotide. (Gabbro in part.) A grayish-white to gray- ish-green, and sometimes olive-green rock, very tough, having G. =2*9-3 4. Consists of saussurite of whitish to greenish and bluish color, mixed either with smaragdite of emerald- green color, or with green to grayish-green diallage ; the diallage generally containing more or less hornblende, and the smaragdite, pyroxene. The saussurite is commonly of either the first or second kind mentioned on page 410 ; but the distribution of these kinds is not fully made out. Labra- dorite is rarely present locally in place of the saussurite. Metamorphic. VARIETIES. a. Diallagic; diallage the chief foliated mineral, b. Smaragditic ; emerald-green smaragdite, the foliated mineral, c. Mi- caceous ; contains mica. d. Serpentinous ; contains some serpentine a rock into which it often graduates, e. Garnetiferous. f . /Schistose ; especially so when talc is present, g. Variolitic ; contains aphani- tic concretionary spheroids of the saussurite mineral, as in the " Vario- lite de la Durance," and of Mt. Genevre, and asociated with ordinary euphotide ; for which concretions Delesse obtained the composition Silica 56 '12, alumina 17 '40, chromium oxide 0*51, iron protoxide 7*79, magnesia 3'41, lime 8'74, soda 3'72, potash 0'24, ignition 1 '93=99-86, and the specific gravity 2*923. The variety obtained at Orezza is the Verde di Corsica, of decorative art. Occurs near Lake Geneva, in Savoy ; at Mt. Genevre in Dauphiny, near the boundary between France and Italy ; at Allevard, in the northeastern part of Isere ; in the valley of the Saas, north of east of the Monte Rosa region ; in the Grisons ; near Leghorn and Bologna ; near Florence, at Mt. Impruneta, it being the Oranitone (page 450) of the Serpentine region ; on Corsica, in the Orezza valley; in Silesia ; in I. of Unst. It is often associated with serpentine ; and the serpen- tine and euphotide form beds in irregular masses among, and as a constituent part of, a series of metamorphic strata, which include green chloritic and talcose schists, limestone (which, at Mt. Genevre, is of the Jurassic formation), and other rocks. For the Mt. Genevre euphotide, Delesse obtained Silica 45'00, alumina and iron oxide 26-83, lime 8 '49, magnesia, soda and potash (by loss) 13 "90, water and carbonic acid 6 '78, and for the saussurite the result stated on page 410. The composition is near that of a labradioryte, and the dif- ference in the two rocks must have depended on the different condi- tions attending crystallization. The mixture of hornblende and py- roxene in either foliated constituent, in connection with their mutual positions and structure, proves that part of the hornblende is altered pyroxene. The remark made on page 410 with reference to the pro- duction of the saussurite may apply also to the foliated hornblende, and therefore to the whole rock. 450 DESCRIPTIONS OF ROCKS. 6. PYROXENE AND SODA-LIME-FELDSPAR SERIES. 1, Augite-Andesyte. Contains the same triclinic feldspar as andesyte, but augite is present in place of hornblende. Amount of silica obtained in analyses about 55 to 58 per cent. Texture crystalline-granular to aphaiiitic ; colors dark gray to greenish-black and brownish-black. G. = 2 '65 - 2 -90. Eruptive. VARIETIES. There are two series : A. Ordinary, that is, without chrysolite, or only in traces. B. Chrysolitic, chrysolite being in disseminated grains or crystals. Under each there are varieties : a. anhydrous ; b. hydrous, or chloritic, and feeble in lustre ; and c. amygdaloidal, as well as chloritic. Again, each of these varieties may be porphyritic. To the hydrous rock, and especially the chryso- litic, the term Melaphyre is sometimes applied. Quartz- Augite- Audesyte is described by Zirkel as occurring in Pali- sade Canon, in Nevada Plateau ; it contains yellowish-brown augite, some biotite, some grains of quartz. Silica 63 '71 per cent. 2. Gabbro or Hyperyte. (Gabbro, in part.). A basic grani- toid rock in part, consisting of cleavable labradorite with dis- seminated pyroxene, or a granular crystalline aggregate of the two minerals. The pyroxene is o'ften foliated, and has been improperly called hypersthene. In place of labrador- ite, the feldspar is sometimes andesite, and sometimes anor- thite. Color, dull flesh-red to brownish-red, also dark-gray, to grayish-black. Tough. G.= 2 '7-3-1, varying with the proportion of pyroxene, which is sometimes small. Con- tains also magnetite or titanic iron. The name Gabbro has been applied to this rock ; also to a coarsely granular igneous rock, consisting chiefly of labradorite and foliated pyroxene, referred beyond to doleryte ; to euphotide ; and, by the Italians, formerly to serpentine. Ferber, in his " Brief e " (1773), says (p. 98): Gabbro of Florence is the same as the rock called "sachsi- schen Serpentin, in Deutschland," that is, the serpentine of Zoblitz. Again, on page 330, he says that Mt. Impruneta, seven Italian miles from Florence, consists of Gabbro, or the so-called Saxon serpentine, and he alludes to the occurrence in it of diallage and amianthus, and the presence also " der sogenannte Granitone " "in horizontalen Sehichten in den Gabbro-Bergen," which sometimes consisted " aus weissem Feldspat, welcher grosse Parallelepipeden formirte," though usually containing diallage. VARIETIES. a. Granitoid ; the feldspar in distinct cleavable grains or masses, b. Fe2dspathose ; the pyroxene feeble in amount, c. Chry- solitic; contains disseminated chrysolite, d. Anorthitic, or Tractolite ; anorthite replaces the labradorite. Includes the so-called hypersthenyte of the Adirondacks, Canada, and Norway. Occurs also in the Laramie Hills, Colorado, a kind which afforded, on analysis, Silica 52-14, alumina 29'17, iron oxide 3 '26, mag- nesia 0-76, lime 10 81, soda 3-02, potash 0'98, ignition 0'58 = 100 '92. KINDS OF ROCKS. 451 3. Noryte. Hypersthenyte. A rock consisting of labrador- ite or oligoclase, with true foliated hypersthene ; from St. Paul's, Labrador, Hitteroe, Egersund, Harzburg; fine grained, in Cortlandt, N. Y., between Cruger's and Peeks- kill. 4. Doleryte. (Basalt, Trap.} Chief constituents, labra- dorite and augite, with magnetite, and sometimes anortbite. Often porphyritic, and the feldspar crystals may be anor- thite. Amount of silica yielded on analysis usually 47 to 52 per cent. Texture crystalline-granular to aphanitic; and often, especially in the latter, having glassy particles among the crystalline, or even an unindividualized base or magma between the crystalline grains the variety called Basalt ; often coarse granular through the body of a dike, while aphanitic along its walls, and sometimes containing glassy portions in the latter when not elsewhere. Colors dark grayish to bluish-black, greenish-black, and brownish- black. 6. =2-75-3-1. Eruptive ; also metamorphic. It includes the larger part of tlie rock usually called trap, abundant inmost regions of igneous eruptions ; constitutes the "trap" ridges of the Connecticut Valley, the Palisades of New Jersey, and similar ridges in Nova Scotia and North Carolina ; also in the Lake Superior region, and extensive beds of so-called basaltic rocks over the Rocky Mountain slopes west of the Front Range. The rock of New Haven, Conn., from West Rock, afforded Silica 51'78, alumina 14*20, iron ses- quioxide 3-59, iron protoxide 8*25, manganese protoxide 0'44, magne- sia 7'63, lime 10'70, soda 2 '14, potash 0'39, loss by ignition 0'63, phos- phorus pentoxide 014=9989; G.=3 03. A hydrous or chloritic variety from Saltonstall's Ridge, near New Haven, afforded Silica 49 '28, alumina 15-92, iron sesquioxide 1-91, iron protoxide 10'20, manganese protoxide 0'37, magnesia 5 '99, lime 7'44, soda 3'40, potash 0'72, water 3-90, carbon dioxide 1-14=100'72 ; G.=2'86. VABIETIES. There are two series : A. Ordinary, B. Chrysolitic, and for the latter the name Pendotyte has been used. Each occurs : a. anhydrous ; b. hydrous, or chloritic, of feeble lustre ; c. amygda- loidal, as well as chloritic ; d. vesicular, or scoriaceous, as in doleritic or basaltic lavas. JSpilite is amygdaloid. Again, each of these varieties may be porphyritic. Again, the augite may be in distinct crystals. A coarse-granular kind, having the pyroxene foliated, is sometimes called gabbro. This basic rock, doleryte, is often called, also, basalt, especially when it has an unindividualized base ; a specimen of this kind, from Nevada, is represented in fig. 7, page 418. The name, anamedte, has been used for an aphanitic kind, but is unnecessary. Diabase. The term diabase is very often applied to doleryte older than Tertiary. It was formerly supposed that the former differed from the latter in bain"- chloritic, and afterwards in never containing glassy particles or an unindividualized base ; but neither distinction holds. 452 DESCRIPTIONS OF ROCKS. The "antique green porphyry," or Porfido verde antico, figured on page 415, in fig. 2, is a porphyritic rock of the composition of doleryte, the feldspar being labradorite, and the other chief constituent, augite, With also some chlorite, or viridite, which last is the source of the greenish color. It is from the South Morea, between Lebetsova and Marathonisi. Delesse obtained, from the compact base, Silica 53*55, alumina 19 '84, iron protoxide 7'35, manganese protoxide 0'85, lime 8*02, soda and potash 7'9o, water 2'67. In view of its firmness, and its contrast in this respect with most chloritic doleryte, it may be queried whether the rock is not a metamorphic doleryte (metadoleryte). It closely resembles the porphyritic labradioryte from the vicinity of New Haven, Conn, (which is chloritic and metamorphic), though differ- ing from it in containing pyroxene instead of hornblende. A similar porphyry is reported from Elbingerode in the Hartz, Belfahy in the Vosges, and Barnetjern near Christiania in Norway. 5. Eucryte. A doleryte-like rock consisting chiefly of an- orthite and augite. Occurs compact, and as a lava. From Elfdalen, Norway. 6. Amphigenyte. (Leucitopliyre.} Contains augite, like doleryte, but leucite (called sometimes amphigene) replaces the feldspar. Dark gray, fine-grained, and more or less cel- lular to scoriaceous. G-. 2-7-2-9. The leucite is dissemi- nated in grains or in 24-faced crystals. Constitutes the lavas of Vesuvius and some other regions. Accessory min- erals, nephelite, biotite, chrysolite, sodalite, sanadin, labra- dorite and nosean. Hauynophyre is an amphigenyte from Vulture, near Melfi, in which hauynite replaces much of the leucite. 7. Nephelinyte. (Nepheline-doleryte. ) Contains augite, like doleryte, but nephelite replaces the feldspar, or the larger part of it. Crystalline-granular ; ash-gray to dark gray. The nephelite is partly in distinct crystals. 8. Tachylyte. Hyalomelan. Blackish glass, or pitchstone, made in connection with augitic igneous rocks or lavas ; the former affords on analysis 49 per cent, of silica, and the latter 55. This Doleryte-pitcJistone may be porphyritic, or contain small grains of augite, or of chrysolite. 7. PYROXENE, GARNET, EPIDOTE, AND CHRYSOLITE ROCKS. CONTAINING LITTLE OR NO FELDSPAR. 1. Pyroxenyte. Coarse or fine granular pyroxene rock. Sometimes chrysolitic, a variety which occurs with chryso- litic hornblendyte at the localities mentioned on p. 446. 2. Garnetyte, or Garnet Rock, A yellowish-white to green- KINDS OF ROCKS. 453 isli- white, tough rock, consisting of an alumina-lime garnet. G.=3-39-3-49. From St. Francis, Canada. The superior yellow iiovaculite or whetstone, of Vieil Salm, Belgium, has the constitution, according to A. Kenard, of a manganesian garnet. Metamorphic. 3. Eclogyte. Compact and tough. Consists of granular garnet and hornblende, with grass-green smaragdite. G. = 3-2-3-5. A related rock consists of reddish or brownish- yellow garnet, and black or greenish-black hornblende, with often some magnetite. Metamorphic. 4. Epidosyte. Pale green to pistachio-green. Consists of epidote mixed with quartz. Metamorphic. 5. Eulysyte. Fine-granular, consisting of chrysolite with a diallage-like mineral and garnet. Forms a bed in gneiss near Tunaberg, Sweden. 6. Chrysolyte, or Chrysolite-Reck. Yellowish to pale olive- green, granular ; consisting almost wholly of chrysolite. G-. =r 3-3-1; H. 5-5-6. Abundant in Macon County, N. Carolina ; in part changed to serpentine. Metamorphic. Dunyte is yellowish-green ; granular, and consists of chrysolite, with some chromite. From Mount Dun, New Zealand. Eruptive. 7. Lherzolyte. Greenish-gray ; crystalline granular. Con- sists of chrysolite, enstatite, whitish pyroxene, with chrome- spinel and sometimes garnet. From Lake Lherz, etc. Is it metamorphic ? 8. Picryte. Blackish-green to brownish-red ; crystalline- granular. Consists of chrysolite, with augite sometimes in crystals. Graduates into chrysolitic doleryte. _ 9. Limburgyte. A semi-glassy rock, consisting of chryso- lite and augite, with some magnetite. It is occasionally amygdaloidal. Affords on analysis 43 per cent, of silica. 8. HYDROUS MAGNESIAN AND ALUMINOUS ROCKS. Contain one or more of the hydrous magnesian minerals, chlorite, talc, serpentine, or the related hydrous aluminous mineral, pyrophyllite. The fine-grained kinds are more or less greasy to the touch ; and some of them resemble the hydromica slates. 1. Chlorite Schist. Schistose ; color dark green to grayish- green and greenish-black ; but little, if any, greasy to the touch. Consists of chlorite, with usually some quartz and 454 DESCRIPTIONS OF ROCKS. feldspar intimately blended, and often contains crystals (usually octahedrons) of magnetite, and sometimes chlorite in distinct scales or concretions. Metamorphic. VARIETIES. a. Ordinary, b. HornUendic ; the hornblende ingrains or needles, c. Magnetitic. d. Tourmalmic. e. Garnetiferous. f. Pyr- oxenic. g. Staurolitic. h. Epidotic. Graduates into argillyte. 2. Chlorite-Argillyte. An argillyte or phyllyte consist- ing largely of chlorite. Metamorphic. 3. Talcose Schist. A slate or schist consisting chiefly of talc. Not common, except in local beds, most of the so- called "talcose slate" being hydromica schist (p. 440). 4. Steatyte, Soapstpne (p. 55). Consists of talc. Mas- sive, more or less schistose ; granular to aphanitic. Color, gray to grayish -green and white. Feels very soapy. Easily cut with a knife. Metamorphic. VARIETIES. a. Coarse-granular, and massive or somewhat schis- tose, b. Fine-granular; "French chalk." c. Aphanitic, or Rens- selaerite; of grayish-white, greenish, brownish to black colors, from St. Lawrence County, N. Y. , and Grenville, Canada. 5. Serpentine. Aphanitic or hardly granular ; of dark- green to greenish-black color, easily scratched with a knife, and often a little greasy to the feel on a smooth surface. Although generally dark green, it is sometimes pale grayish and yellowish-green, and mottled. Metamorphic. Varieties. a. Noble; oil -green and translucent, b. Common; opaque, and of various colors, c. Schistose, d. Diallagic ; contains green or metalloidal diallage. e. Chromiferous; contains chromite, a chromium ore belonging to serpentine regions, f . B. Stibnite. Apatite, 46, 48, 49, 67, 213. Aphanesite, 139. Aphrodite, 307. Aphrosiderite, 319. Aphthitalite, 227. Apjohnife; 198. Aplome, 258. Apophyllite, 294. Aquamarine, 252. Aragonite, 218. Aragotite, 324. Arcanite, 227. Arfvedsonite, 252. Argentine, 121, 216". Argentite, 117, 121. Argillyle, 428. Arkansite, 163. Arkose, 436. Arksutite, 197. Arquerite, 117. Arragonite, 218.. Arsenate, Calcium, 214. Cobalt, 167, 168. Copper, 139. Iron, 185. Lead, 152. Uranium, 170, 171. Zinc, 156. Arsenic, Native, 98. Arsenic group, 98. sulphide, 99. White, 99. Arsenical antimony, 101. cobalt, 165 r 166, iron ore, 175, 176. lead ores, 149. nickel, 165, 166. Arsenide, Cobak r 165^ 166i Copper, 135. Iron, 175, 176. Manganese, 188. Nickel, 165, 166. Arsenioaiderite, 185. Arsenolite. 99. Arsenopyrite, 175. Asbestua, 246, 250. Blue, -0. Crocidolite. Asbolan, Asbolite, 167. Asmanite, 241. Asparagus-stone, 213. Aspasiolite, 315. Asphaltum, 326. Aspidolite, 266. Astrakanite, v. Blodite. Astrophyllite, 266. Atacamite, 136. Atopite, 214. Auerbachite, 260. Augite, 245. andesyte, 450. Augitic trachyte, 448. Aurichalcite, 141, 157. Auriferous pyrite, 173. Auripigmentum, 99. Automolite, 196. Autunite, 170. Aventurine quartz, 235. feldspar, 279. Axinite, 44, 264. Azurite, 141. Babingtonite, 247. Bagrationite, ID. Allanite. Baltirnorite, 308. Banatite, 447. Barite, 220. Barium, Compounds of, 220. Barytes, 220. Barytocalcite, 222. Basalt, 451. Basanite, 237. Bastite, 309. Bathvillite, 325. Beaumontite, 304. Bechilite, 212. Benzole, 324. Berthierite, 176. Beryl, 46, 252. Berzelianite, 135. Beyrichite, 165. Bieberite, 168. Biharite, 312. Bindheimite, 152. Binnite, 136. Biotite, 266. Bismite, 102. Bismuth, 101. Bismuth glance, . Bismuthinitc. Bismuth ores, 102. carbonate, 102. Bismuth nickel, 166. Bismuth silver, 116. Bismuthinite, 102. Bismutite= Bismuth carbonate. GENERAL INDEX. 459 Bismutoferrite, 256. Bitter spar, v. Dolomite. Bitumen, 326. Elastic, 324. Bituminous coal, 327. Bituminous shale, 428. Black cobalt, 167. copper, 137. jack, 155. lead, 107. silver, 119. Blende, 154. Blodite, 206, 227. Blomstraudite, 170. Bloodstone, 237. Blue iron earth, 185. copper, 133. vitriol, 137. Bodenite, 263. Bog iron ore, 181. manganese, 190. Bole, Halloysite, 312. Boltonite, 256. Boracic acid, 97. Boracite, 206. Borate, Ammonium, 231. Calcium, 212. Hydrogen, 98. Iron, 182. Magnesium, 206. Sodium, 212, 227. Borax, 227. Bornite, 134 Borocalcite, 212. Boronatrocalcite, 212. Boron group, 97. Bort, 103. Bosjemanite, 198. Botryogen, 182. Botryolite, 289. Boulangerite, 149. Bournonite, 136. Boussingaultite, 231. Bowenite, 309. Bragite, 260. Branchite, 324. Brandisite, 320. Brass, composition of, 144. Braunite, 189. Bravaisite, 302. Breccia, 426. Bredbergite, 258. Breislakite, v. Pyroxene. Breithauptite, 166. Breunerite = Ferriferous Magne- site. Brewsterite, 304. Brittle silver ore, 119. Brochantite, 138. Bromargyrite, 121. Bromic silver, 121. Bromlite, 222. Bromyrite, 121. Brongniardite, 120, 149. Bronze, 144. Bronzite, 244. Brookite, 163. Brown coal, 327. hematite, 181. iron ore, 181. ochre, 181. spar, 219. stone, 427. Brucite, 204. Brushite, 214. Bucholzite, 285. Bucklandite, 262. Buhrstone, 437. Buratite, 141, 157. Cacholong, 240. Cacoxenite, Cacoxene, 185. Cadmium, Ores of, 159. Cairngorm stone, 235. Caking coal, 327. Calaite, v. Callaite. Calamine, 157, S96. Calaverite, 115. Calcite, 49, 50, 215. Calcium, Compounds of, 207. Calc spar, 215. Caledonite, 149. Callainite, 200. Callais, Callaite, 200. Calomel, 129. Canaanite= White Pyroxene, 245. Cancrinite, 270. Cannel coal, 327. Cantonite, near Covellite, 133. Caoutchouc, Mineral, 324. Capillary pyrites, 164. Carbonaceous shale, 428. Carbonado, 103. Carbonate, Ammonium, 231. Barium, 221. Calcium, 215, 218, 219. 460 GENERAL INDEX. Carbonate, Bismuth, 102. Cerium, 203. Copper, 140, 141. Iron, 185. Lanthanum, 203. Lead, 152. Magnesium, 207, 219, Manganese, 191. Sodium, 229, 230. Strontium, 223. Uranium, 171. Yttrium, 203. Zinc, 156. Carbonic acid, 108, 423. Carburetted hydrogen, 321. Carnallite, 205. Carnelian, 236. Carpholite, 296. Carrara marble, 433. Cassiterite, 160. Castor, Castorite, 249. Catapleiite, 295. Cataspilite, 312. Catlinite, 429. Cat's-eye, 236. Celadonite, 307. Celestite, Celestine, 222. Cerargyrite, 120, 121. Cerite, 298. Cerium ores, 201. Cerolite, 309. Cerussite, 152. Cervantite, 101. Chabazite, 800. Chalcanthite, 137. Chalcedony, 235. Chalcocito, 133. Chalcodito, 307. Chalcolite, 170. Chalcomorphite, 296. Chalcophanite, 189. Chalcophyllite, 139. Chalcopyrite, 133. Chalcosiderite, 185. Chalcosine, 133. Chalcostibite, 136. Chalcotrichite= Capillary Cuprite, 136. Chalk, 215, 432. Chalybite Siderite. Chathamite, . Rhodochrosite. Diamond, 103. Dianite, u. Columbite. Diaphorite = Trimetric Frelesleb. enite. Diaspore, 194. Dichroite, 264 4G2 GENERAL INDEX. Bickinsonite, 191. Didymium ores, 201, 203. Bihydrite, 139. Binite, 324. Biopside, 246. Dioptase, 141, 256, 295. Bioryte, 446. Biphanite, 319. Bipyre, 209. Bisterrite, 320. Bisthene, 286. Bitroyte, 444. Bog-tooth Spar, 215. Bolerophanite, 138. Boleryte, 451. pitchstone, 452. Bolomite, 207, 219. Bolomyte, 43'3, 434. Bomeykite, 135. Bomyte, 443. Breelite, 221. Bry-bone, 158, 364. Budleyite, 320. Bufrenite, 185. Bufrenoysite, 149. Bunyte, 453. Burangite, 199. Butch white, 221. Bysanalyte, 202, 214. Byscrasite, 119. Bysluite, 196. Bysodile, 325. Bysyntribite, 312. Earthy cobalt, 167. Ecdemite, 152. Eclogyte, 453. Edelforsite, 245. Edenite, 251. Edingtonite, 296. Edwardsite, . Monazite. Ehlite, 139. Ekebergite, 269. Ekmannite, 316. Elseolite, 269. Elaterite, 324. Electro-silicon 430. Electrum, 110 Eliasite, 170. Embolite, 121. Embrithite, v. Boulangerite. Emerald, 252. Oriental, 193. Emerald, nickel, 168. Emery, 193. Emerylite, 319. Emplectite, 136. Enargite, 136. Enceladite, . Warwickite. Eustatite, 244. Enysite, 138. Eosite, near Vanadinite. Eosphorite, 200. Epichlorite, 316. Epidosyte, 453. Epidote, 262. Epistilbite, 302, 304. Epsom salt, Epsomite, 205. Erbium ores, 201. Erdmannite, 296. Erinite, 139. Erubescite, 134. Erythrite, 167. Esmarkite, 265, 315. Eucairite, 118, 135. Euchroite, 139. Euclase, 288. Eucolite, 254. Eucrasite, 296. Eucryte, 452. Eudyalite, Eudialyte, 254, 260. Eudnophite, 300. Eukairite, V. Eucairite. Eulysyte, 453. Eulytite, Eulytine, 102, 256. Euosmite, 325. Euphotide, 449. Euphyllite, 314. Eupyrchroite, 213. Euralite, 318. Euryte, 442. Euxenite, 202. Fahlerz, 135. Fahlunite, 265, 314. Fairfieldite, 191. Fassaite, 246. Faujasite, 300. Fayalite, 256. Feather ore, v. Jamesonite. Feldspar Group, 272. Felsite, 280. Felspar, v. Feldspar. Felsyte, 442. Fergusonite, 202, 260. Fibrofemte, 182. GENERAL INDEX. 463 Fibrolite, 285. Fichtelite, 324. Fiorite, 240. Fioryte, 437. Fireblende v. Pyrostilpnite. Fire-marble, 431. Fire-opal, 239. Fischerite, 200, Flint, 237. Float-stone, 241. Flos ferri, 218. Flueliite, 197. Fluidal texture, 418. Fluocerine, 202. Fluocerite, 202. Fluor-apatite, 213. Fluor, Fluorite, 208. Fluor spar, 208. Fluorides, Aluminum, 197. Calcium, 208. Foliated tellurium, 149. Fontainebleau limestone, 216. Foresite, 304. Forsterite, 255. Fowlerite, 247. Foyayte, 446. Franklinite, 158, 179, 456. Free-stone, 427. Freibergite Argentiferous Tetra- hedrite. Freieslebenite, 120, 121, 149. Frenzelite, 102. Friedelite, 256. Gabbro, 449, 450, 454 Gadolin, Gadolinite, 203, 263. Gagates, 328. Gahnite, 196. Galena, Galenite, 121, 145. Galmei, 157. Ganomalite, 153. Garnet, 256. rock, 452. ; Garnetyte, 452. Garnierite, 168. Gastaldite, 252. Gay-Lussite, 230. Gearksutite, 197. Gehlenite, 284. Genthite, 168, 309. Geocerite, 325. Geocronite, 149. Geomyricite, 325. Gersdorffite, 166. Geyserite, 240, 437. Gibbsite, 194. Gieseckite, 270, 313. Gigantolite, 265 315. Gillingite, 316. Girasol, 239. Gismondite, Gismondine, 296. Glagerite, 312. Glaserite, v. Arcanite, Glass, 416. Glauber salt, 41, 68, 226. Glanberite, 227. Glaucodot=Cobaltic Arsenopyrite. Glaucolite, 269. Glauconite, 307, 429. Glaucophane, 252, 446. Globulites, 416. Gmelinite, 301. Gneiss, 439. Gold, 109. Goslarite, 156. Gothite, 182. Grahamite, 326. Gramenite, 307. Grammatite, 249. Granite, 437, Granitone, 449, 450. Granular quartz, 435. Granulyte, 439. Graphic granite, 438, 439. tellurium, 118. Graphite, 107. Grastite, 319. Gray antimony, . Stibnite, copper, 135. Green earth, 307. sand, 429. Greenockite, 159. Greenovite, 290. Greenstone, 446, 448. Greisen, 441. Grindstones, 427. Grit, 426. Grochauite, 319. Groppite, 314. Grossularite, 257. Grunauite, 166. Guadalcazarite, 129. Guanajuatite, 102. Guano, 213. Guarinite, 291. Gummite, 170. 4-G4 GENERAL INDEX. Gurhofite, 219. Guyaquillite, 325. Gymnite, 309. Gypsum, 56, 210. Gyrolite, 293. Haidingerite, 214 Hair-salt, 205. Halite, 224. Hallite, 318. Halloysite, 312. HalotricMte, 182, 198. Hamburg 1 white, 221. Harmotome, 301. Harrisite, 133. Haitite, 324. Hatchettite, Hatchettine, 324. Hatchettolite, 170, 214. Hauerite, 188. Haureaulite, 191. Hausmannite, 189. Hauyne, Haiiynite, 270. Hauynophyre, 452. Haydenite, 301. Hayesine, 212. Heavy spar, 220. Hebronite, 199. Hedenbergite, 246. Hedyphane, 152. Heliotrope, 237. Helminthe, 319. Helvite, Kelvin, 256. Hematite, 176, 455. Brown, 181, Red, 176. Hemi-dioryte, 443. Henwoodite, 200. Hercynite, 196. . Herderite, 199. Herschelite, 301. Hessite, 118. Hetaerolite, 189. Heterosite, 191. Heulandite, 303. Hisingerite, 315. Hcernesite, 207. Homilite, 289. Honey-stone, 201. Hopeite, 158. Hornblende, 249, 251. schist, 446. Horn quicksilver, 129. silver, 120. Hornstone, 237. Horse-flesh ore, v. Bornite. Hortonolite, 256. Houghite, 194. Howlite, 212. Huascolite, 155. Hiibnerite, 183. Hudsonite, 246. Humboldtilite, 261. Humboldtite, 289. Humite, 281. Hureaulite, 191. Hyacinth, 259, 260, 284. Hyalite, 240. Hyalomelan, 452. Hyalophane, 276. Hyalosiderite, 255. Hyalotecite, 153. HydrargiJlite, 194. Hydraulic limestone, 217, 431 Hydroboracite, 212. Hydrocarbons, 320. Hydrocerussite, 153. Hydrochloric acid, 231. Hydrocyanite, 138. Hydrodolomite, 220. Hydrogen, 231. Hydromagnesite, 204, 207. Hydro-mica Group, 312. Hydromica schist, 440. Hydrophane, 240. Hydrophite, 309. Hydrotalcite, 194. Hydrozincite, 157. Hypersthene, 244. Hypfrsthenyte, 450, 451. Hyperyte, 450. Iberite, 315. Ice, crystallization of, 4. Iceland spar, 215. Idocrase, 261. Idrialine, Idrialite, 324. Ihleite, 182. Ilmenite, 178. Ilvaite, 263. Inclusions, 423. Indianite, 275. Indicolite, 283. Infusorial earth, 241. lodargyrite, 121. Iodide, Mercury, 129. Silver, 121. lodyrite, 121. GENERAL INDEX. 465 lolite, 264. Hydrous, Slo". lonite, 325. Iridosmine, 127. Iron, 171. Iron, Ores of, 171, 455. Magnetic, 178, 455. pyrites, 172. sinter, 185. Ironstone, Clay, 177, 181. Isenite, 448. Iserine, u. Menaccanite. Isoclasite, 139. Itabyrite, 440, 455 Itacolumyte, 104, 436. Ittnerite, 270. Ixolyte, 324. Jade, 250. Jadeite, 263. Jamesonite, 149. Jargon, 260. Jarosite, 182. Jasper, 237. rock, 437 Jaspery clay iron-stone, 177. Jefferisite, 317. Jeffersonite, 246. Jelletite, 258. Jenkinsite, 309. Jenzscliite, 241. Jet, 328. Johannite, 171. Jollyte, 316. Joseite, 102. Kalinite, 198. Kammererite, 318. Kaneite, 188. Kaolin, Kaolinite, 280, 310. Karyinite, 152. Keiihauite, 203, 291, Kermesite, 101. Kerrite, 318. Kersanton, Kersantyte, 444 Kerstenite, 150. Kieserite, 205. Killinite, 248. Kinzigyte, 444. Kjerulftne, 207. Knebelite, 256. Kobellite, 149. Kochelite, 202. Kongsbergite, 117. Konigite, Konigine, 138. Konlite, 324. Kottigite, 156, 167. Kotschubeite, 319. Kreittonite, 196. Krennerite, 116. Krisuvigite, 138. Kronkite, 138. Kupfferite, 252. Kyanite, 286. Labradioryte, 448. Labrador feldspar, 27(5. Labradorite, 276. Labradorite-dioryte, 448. Lagonite, 182. Lampadite, 190. Lanarkite, 151. Langite, 138. Lanthanite, 203. Lanthanum ores, 201. Lapis-lazuli, 270. Lapis ollaris, 304. Larderellite, 231. Latrobite, v. Anorthite. Laumontite, Laumonite, 293. Laurite, 127. Lazulite, 199. Lead, ores of, 145 Leadhillite, 151. Lecontite, 231. Lederite, 291. Lehrbachite, 149. Lenzinite, 312. Leopoldite, v. Sylvite. Lepidokrokite, 182. Lepidolite, 268. Lepidomelane, 266. Leptinyte, 439. Lettsomite, v. Cyanotrichite. Leuchtenbergite, 319. Leucite, 271 Leucitophyre, 452. Leucityte, 443. Leucophanite, 256. Leucopyrite, 176. Levyne, Levynite, 301. Lherzolyte, 453. Libethenite, 139. Liebigite, 171. Lievrite,