Geol ogy 
 
The Mineralogy of Arizona 
 
 BY 
 
 F. N. GUILD 
 
 Professor of Chemistry and Mineralogy, University of Arizona 
 
 EASTON, PA. 
 THE CHEMICAL PUBLISHING CO. 
 
 1910 
 
 LONDON, ENGLAND: 
 
 WILLIAMS & NORGATE 
 
 14 HENRIETTA STREET, COVENT GARDEN, W. D. 
 
COPYRIGHT, 1910, BY EDWARD HART 
 
INTRODUCTION 
 
 It is well known to students of mineralogy that the greater num- 
 ber of interesting minerals are found at some depth below the 
 surface in regions where the destructive effect of erosion and the 
 decomposing action of meteoric water are not active and hence can 
 be reached only by expensive exploitation rarely undertaken ex- 
 cept when compensation is hoped for. in the possible discovery of 
 the precious or useful metals. Arizona is attracting considerable 
 attention on account of its unusual mineral resources, and its 
 mountains and canons are filled with excavations which are evi- 
 dences of the enthusiasm with which the search is carried on. 
 Thus formations are penetrated and minerals exposed to view 
 which, lacking this incentive, would never have been discovered. 
 
 In certain respects many of the minerals in Arizona are suffi- 
 ciently unusual in their mode of occurrence and in their composi- 
 tion to warrant special attention. The rather common occurrence 
 of vanadium, tungsten and molybdenum, associated with deposits 
 of economic value, has been the subject of frequent mention in the 
 scientific journals. These are of great interest, not only from the 
 variety and beauty of the crystallizations presented, but, contain- 
 ing as they do, elements of considerable rarity, because the chem- 
 ical and geological conditions which have given rise to them de- 
 mand investigation. The object of this publication, then, is to 
 give a fairly complete description of Arizona's minerals with some 
 reference to their mode of occurrence, associations and chemical 
 composition. The order of treatment is in accordance with the 
 well known classification of Dana. The elements found as min- 
 erals are considered first ; then the sulphides and others, as out- 
 lined in the following table. 
 
 819491 
 
CLASSIFICATION AND ORDER OF TREATMENT 
 
 PAGE 
 
 I. Native Elements 5 
 
 II. Sulphides, Arsenides, Etc 23 
 
 III. Sulpho-salts, Sulpharsenites, Etc. 31 
 
 IV. Chlorides, Fluorides, Bromides, Etc. 33 
 
 V. Oxides 36 
 
 VI. Oxygen Salts 46 
 
 1 i) Carbonates 46 
 
 (2) Silicates 56 
 
 (3) Phosphates, Vanadates, Etc 73 
 
 (4) Sulphates < 83 
 
 (5) Tungstates and Molybdates 92 
 
 VII. New Minerals Discovered in Arizona 97 
 
I. NATIVE ELEMENTS 
 
 Diamond, C 
 
 Composition and Artificial Production. The diamond 
 is crystallized carbon not different in its chemical com- 
 position from pure charcoal. Because of the simplicity 
 of its composition, attempts have repeatedly been made 
 in chemical laboratories to produce it. The method of 
 investigation usually consists in dissolving carbon in 
 molton iron or similar media, and allowing it to crystal- 
 lize while cooling. Until recently all such attempts 
 have failed, owing to the habit of carbon to crystallize in 
 the form of graphite rather than in its other possible 
 form, the diamond. Moisson, however, succeeded in 
 producing the diamond by heating iron in which 
 carbon was dissolved to a temperature of 3000 C. by 
 means of an electric furnace, and suddenly cooling the 
 mass by plunging it into cold water. By this simple 
 method a cold solid shell was formed, which on contract- 
 ing, subjected the remaining liquid mass to enormous 
 pressure. Under these extraordinary conditions a part 
 of the carbon crystallized in the form of diamond. 
 The product, however, was too small and in crystals too 
 imperfect to warrant much hope that by this means 
 diamonds of sufficient size and brilliancy could be pro- 
 duced to serve as gems. 1 These investigations, together 
 with the researches on meteorites described below, sug- 
 
 i Comptes rendus de T Academic des Sciences. 116, 218. 
 
6 THE MINERALOGY OF ARIZONA 
 
 gest a possible origin of the gem in nature, the factors 
 in its formation being a solution of carbon in a basic 
 magma and high pressure. 
 
 Terrestrial Diamond. Although diamonds have been 
 found in many of the states, notably in North Carolina, 
 Virginia, Oregon, California and Wisconsin, Arizona has 
 yet to report an authentic discovery of this valuable gem 
 mineral. In 1870, however, a company was organized 
 for the exploitation of diamonds and other gems in 
 Arizona and New Mexico. It is said that 80,000 carats 
 of so-called rubies and many diamonds purporting to 
 have been collected from these fields, were displayed to 
 prospective stock buyers. Expeditions to the locality 
 were made, and in a week's time as many as 6,000 carats 
 of rubies and 1,000 carats of diamonds are said to have 
 been gathered. Finally, Mr. Clarence King, then Direct- 
 or of the United States Geological Survey, made a trip 
 to these famous gem fields, and succeeded in bringing to 
 light the fact that an American had actually purchased 
 in London a large quantity of rough diamonds with 
 which the deposit had been salted ; salted, in fact, so 
 thoroughly that an occasional diamond was picked up in 
 this district even several years after the event. 1 The in- 
 cident is well characterized by Hintze in his Handbuch 
 der Mineralogie as a " grossartige Schwindel." 
 
 Diamonds are most frequently associated with perido- 
 tites, serpentines and other ultra-basic rocks, or the 
 debris accompanying such rocks, a fact that should be 
 borne in mind by the mineralogist or miner while search- 
 
 1 Kunz : Gems, p. 36. 
 
NATIVE ELEMENTS 7 
 
 ing for these gems. The recent discovery of diamonds 
 in Arkansas, where they are found in peridotitic rock 
 material similar to the South African fields, is a good 
 illustration of this very characteristic mode of occurrence. 
 These types of rocks, though not abundant in Arizona, 
 are present in certain localities, and they might well be 
 the subject of special research for these gems as well as 
 other minerals known to occur associated with them. 
 
 Meteoric Diamond. The presence of crystallized car- 
 bon or the diamond in meteoric iron was first proved by 
 Jerofejew and Latschnow, in 1888, in their investigations 
 of the meteor which fell in Nowo-Urei, Krasnoslobodsk, 
 Russia, on the 22d day of September, 1886. Since that 
 time the diamond has been found in meteoric iron in 
 widely different localities, but notably, perhaps, in the 
 Canon Diablo specimens found near Coon Mountain, or 
 Crater Mountain, in the northern part of Arizona. 
 Papers on the subject of diamonds in these meteoric 
 masses have appeared by Foote and Koenig, 1 by Hunting- 
 ton and Kunz, by Friedel, 2 by Cohen, and by others. 
 Moisson, in his researches on the artificial production of 
 the diamond in the electric furnace, directed special at- 
 tention to the occurrence of this mineral in the Arizona 
 meteorites. Some of the crystals obtained by him meas- 
 ured 0.7 by 0.3 millimeters. They were yellow in tint, 
 of rough surface, and transparent. 3 
 
 1 Am. Jour. Sci., 1891, 43, 413. 
 
 2 Bui. Soc. Min., Paris, 1892, 15, 285. 
 
 * Moisson : I<e Four IJlectrique, p. 140. 
 
8 THE MINERALOGY OF ARIZONA 
 
 Graphite, C 
 
 So far as the writer knows, pure graphite has not been 
 found in Arizona. A black, graphite-like clay is found 
 in large quantities near Benson, and will be described 
 under Graphitic Clay. 
 
 Seams of what appeared to be impure graphite in black 
 carbon shales have frequently been observed, but no 
 analyses have been made. 
 
 Sulphur, S 
 
 Sulphur has been found in very small quantities in 
 some of the crater cones near Sunset Peak, in the San 
 Francisco mountains near Flagstaff. Abundant silicious 
 sinter occurs here, showing that a solfataric period fol- 
 lowed the more active stages of vulcanism. The sinter 
 is frequently of a pure sulphur yellow tint and has been 
 mistaken by many tourists for sulphur. 
 
 Arsenic, As 
 
 Attention has recently been called to an interesting 
 occurrence of this element in Washington Camp, Santa 
 Cruz County. 1 Here it occurs in reniform masses, some- 
 times several pounds in weight attached to the walls of a 
 small pocket in dolomitic limestone. The latter is highly 
 metamorphic and crossed by veins carrying lead, copper 
 and zinc minerals. Intrusive rocks are abundant in the 
 district and are considered to be concerned in some way 
 with the mineralization of the limestone. The action 
 especially concerned with the deposition of the arsenic is 
 supposed to be fumerolic. 
 
 1 C. H. Warren : Amer. Jour. Sci., 4th series, 16, 337. 
 
NATIVE) ELEMENTS 9 
 
 Gold, Au 
 
 As is well known, native gold occurs in many localities 
 in Arizona both as placer deposits and vein formations. 
 
 Nuggets of, the value of $400.00 each have been taken 
 from the Weaver placers. 1 Other well known placers are 
 those of Graterville, Canada del Oro in the Catalina 
 mountains, L,inx Creek near Prescott, etc. A description 
 of these deposits, as well as of the gold veins of Arizona, 
 would appear more properly, perhaps, in a publication 
 on mines than in one on mineralogy. A few rather in- 
 teresting modes of occurrence may, however, be men- 
 tioned. 
 
 Native Gold in Igneous Rocks. An unusual occurrence 
 of this kind was recently called to the writers attention 
 by Mr. G. W. Maynard, a mining engineer of New York 
 City. The gold is found in thin paper-like incrustations 
 in the fine cracks of a rhyolitic rock, which occurs on 
 the northeast slopes of the Catalina mountains, near 
 Tucson. The rock is somewhat brecciated in places, the 
 fragments, also rhyolite (felsite), being partially digested 
 by the magma. The rock, when crushed and panned, 
 shows a distinct color of gold, but analyses never give 
 more than a trace of the precious metal. Mr. G. P. 
 Merrill 2 and W. P. Blake 3 have described the occurrence 
 of gold in granite, and Mr. Moericke* its occurrence in a 
 trachitic rock. In all of these cases the gold seems to be 
 
 1 W. P. Blake : Rep to Gov., 1899. 
 
 2 Am. Jour. Sci., 4th series, i, p. 309. 
 
 3 Am. In. Min. Eng., 26, 290. 
 
 * Tschermaks : Min. u. Pet. Mit., Ill, 1891. 
 
IO THE MINERALOGY OH ARIZONA 
 
 primary, sometimes embedded and even completely en- 
 veloped in crystals of quartz and feldspar. In the rocks 
 of the Catalina mountains it would seem quite probable 
 that the gold is secondary, having been deposited in the 
 minute cracks by percolating solutions. Quite likely the 
 gold originally existed in the eruptive but in such minute 
 quantities that it could be detected only after the 
 concentration described above had taken place. The 
 writer has frequently observed similar superficial min- 
 eralization along joint planes, especially in the case 
 of copper where the country rock has become quite deeply 
 stained. These have often led to expensive and useless 
 exploitations. 
 
 Gold in Crystallized Calcite. Some years ago a small 
 sample of vein material was received by the writer from 
 the Vekol mining district which consisted chiefly of 
 white quartz and cleavage masses of calcite. Embedded 
 in the latter were several small grains of gold about two 
 millimeters in diameter. It might at first seem that the 
 gold had been formed by the same processes and at the 
 same time as the calcite. A closer inspection, however, 
 showed that the grains of gold were in reality attached 
 to quartz and were projecting into a cavity, which later 
 became filled with the enclosing calcite. 
 
 Gold in Cerussite. This unusual mode of occurrence 
 has been observed in specimens from Oro Blanco. One 
 large sample, weighing several pounds and consisting al- 
 most entirely of cerussite, was found to contain nearly 
 one ounce of gold per ton. The gold was in a very fine- 
 
NATIVE ELEMENTS n 
 
 ly divided state and could rarely be seen even by the aid 
 of a hand lens. The association being so intimate in this 
 case one is inclined to look upon the gold as having been 
 deposited at the same time and under identical conditions 
 as the carbonate, although it is usually held that gold is 
 not deposited from the same media as those which give rise 
 to lead minerals, especially lead minerals occurring in the 
 oxidized zone. Even where lead minerals are found in 
 the same deposit as gold, the gold is usually either in the 
 gangue or in some accessory mineral. This is well illus- 
 trated in the ores from the Elkhart mine, near Chloride, 
 Mohave Co. , Arizona. The chief minerals found here 
 are quartz gangue, galena and pyrite, and the ore is 
 worked chiefly for its values in gold and silver. Silver 
 is found to accompany the galena and gold the iron 
 pyrite. 
 
 Silver, Ag 
 
 Native silver has been found in the Silver King mine, 
 Final Co., and in small quantities associated with argen- 
 tiferous ores, in other mines of the State. 
 
 Copper, Cu 
 
 Native copper is frequently found in the zone of oxide 
 enrichment in many of the copper mines of the State. 
 It is especially abundant at Bisbee, in the Copper 
 Queen mines, the Shattuck, and others, where it occurs 
 in sheets, nodules and aborescent growths associated with 
 cuprite, kaolin, calcite, limonite, and other minerals. It 
 is interesting to note that in the Holbrook shaft, espec- 
 ially in the neighborhood of the 400 ft. level, the ore 
 
12 THE MINERALOGY OF ARIZONA 
 
 lenses contain considerable chalcocite. These have fre- 
 quently become oxidized only on their margins. This 
 has become a guide to the miners, and when striking na- 
 tive copper after driving through barren ground, they 
 know they are about to reach a rich ore shoot. When 
 they are in ore and strike native copper they believe that 
 they are near the end of the rich deposit. A large sample 
 of native copper presented to the University, by Dr. H. 
 W. Fenner, of Tucson, shows delicate sponge-like forms 
 consisting of aborescent masses altered superficially to 
 malachite. Another interesting mode of occurrence ob- 
 served in situ by the mining class of the University while 
 on one of its annual trips, was that of delicate mosslike 
 masses containing embedded rhombs of calcite of almost 
 perfect development. In the mines of Cananea, Mexico, 
 the mode of occurrence is somewhat different. Here the 
 native copper is found in thin sheets and slabs between 
 the fracture planes in brecciated quartzite, and is not so 
 often associated with the other enrichment minerals of 
 copper. 
 
 Native Copper in Epidote. Many of the copper deposits 
 of Arizona are in a contact zone associated with garnet, 
 epidote, and other minerals characteristic of contact 
 metamorphism. It is not often, however, that the min- 
 erals of copper, and especially native copper, appear in 
 the same hand specimen as the contact minerals men- 
 tioned above. Samples showing this intimate association 
 have been received at the University from two distinct 
 localities, one from the northern part of the State, 
 
NATIVE ELEMENTS 13 
 
 the exact place unknown, and the other from the Santa 
 Rita mountains, south of Tucson. The two samples 
 were almost identical in appearance. They were made 
 up of hard, compact epidote of the characteristic yellow 
 color, and in places contained as many as forty or fifty 
 brilliant grains of copper to one square inch of surface. 
 These vary in size from a fraction of a millimeter to two 
 or three millimeters in diameter. The epidote from the 
 Santa Rita locality is slightly altered by the infiltration 
 of both calcite and silica. It may be possible that the 
 presence of the copper is due to the same secondary 
 action. 
 
 Native Copper in a Trap Rock. Although this mode 
 of occurrence has been observed only in case of a dike 
 found in Sonora, Mexico, it is considered of sufficient in- 
 terest at this point to warrant a brief description. The 
 rock is found near Washington Camp, Arizona, only a 
 few hundred feet from the Mexican line. It is quite un- 
 decomposed in appearance. Fresh fractures show it to 
 be a dark colored, almost black eruptive, presenting in 
 places the characteristic orphitic structure of the diabases. 
 The rock is crossed by many small fracture planes, along 
 which remarkably slight alteration has taken place. Yet 
 it is along these planes that the copper appears as thin 
 paper-like fillings and aborescent incrustations, giving 
 the surface of the rock as it is broken open a metallic, 
 moss-like appearance. Under the petrographic micro- 
 scope, the rock is found to be a quite typical diabase, 
 with orphitic structure fairly well developed, with the 
 
14 THE MINERALOGY OF ARIZONA 
 
 exception that the feldspars contain numerous and re- 
 markably large inclusions of the pyroxenes. The latter 
 mineral is but slightly altered to chlorite, while the feld- 
 spars are sufficiently fresh to show the characteristic 
 polysynthetic twinning of the plagioclases. The copper 
 appears as small bunches and in thin threads, which 
 sometimes nearly cross the field of the microscope. 
 These are, of course, cross sections of the fracture planes 
 mentioned above. The threads are sometimes not more 
 than 0.02 millimeters in width and several millimeters in 
 length. The copper has evidently been brought in and 
 deposited by solutions which have not materially affected 
 the rock through which they passed. The metal may 
 have been derived from other portions of the dike, or 
 more probably from other mineralized rocks in the 
 vicinity. 
 
 Platinum, Pt 
 
 Traces of this metal have been reported by the United 
 Geological Survey, 1 in a sample of black sand from near 
 Prescott, and in another sample of the same material from 
 near Columbia. At the University of Arizona several 
 samples of supposed platinum ore have been investigated, 
 but always with negative results. 
 
 Iron, Fe. 
 
 Native iron is not often found as an original con- 
 stituent of the earth's crust. It has been observed, how- 
 ever, in nearly every part of the world in the form of 
 meteoric iron. These fragments are simply inter-planetary 
 
 1 Mineral Resources, 1905. 
 
NATIVE; EI,EMENTS 15 
 
 particles which the earth picks up during its journey 
 through space. These particles have been seen to strike 
 the earth and having been examined before they have 
 had time to become cold, there is no doubt as to their 
 immediate origin. It is claimed 1 that during every 24 
 hours the earth encounters many millions of these frag- 
 ments, and, were it not for the protecting influence of our 
 atmosphere, the vegetation and animal life would soon 
 be destroyed owing to the continual impact of these mi- 
 nute projectiles. The atmosphere serves as a protecting 
 medium through which these minute bodies are unable 
 to pass without becoming thoroughly disintegrated into 
 a fine dust, due to the high temperature caused by friction. 
 Though very few of them ever reach the earth in a 
 compact form, yet the weight of our planet is yearly in- 
 creasing at the rate of a few tons as a result of these ad- 
 ditions. Indeed, it is even believed by many geologists 
 that our planet and the other heavenly bodies owe their 
 origin to this source rather than to a central molten or 
 gaseous mass which by centrifugal action has suc- 
 cessively thrown off masses that have developed into 
 planets, moons, etc. 
 
 The Tuscon Meteorites. Two important masses of 
 meteoric iron have been discovered in the vicinity of 
 Tucson, but thoroughly reliable data as to the exact 
 point where they fell seem to be lacking. The majority 
 of the reports mention the Santa Rita mountains, south 
 of Tucson, as the original locality, while a few author- 
 ities refer to the fall as having taken place in the ' 'Santa 
 
 1 Todd : New Astronomy, p. 412. 
 
l6 THE MINERALOGY OF ARIZONA 
 
 Catarina" mountains north of Tucson. The fact that 
 Mexico is sometimes mentioned is to be expected since 
 at that time Tucson and vicinity were a part of that 
 country. 
 
 According to Mr. L,. Fletcher 1 the attention of the 
 scientific world was first called to these meteorites through 
 
 Fig. i. The Tucson Ring Meteorite as originally seen in a blacksmith 
 
 shop in Tucson, where it was employed as an anvil. 
 
 (Drawn by Geo. Nishihara from an old wood cut in Bartlett's 
 
 Explorations, Vol. II, 1854.) 
 
 the verbal report of the entomologist, Dr. J. L,. I,eConte 
 of Philadelphia, at a meeting of the American Association 
 for the Advancement of Science held at Albany in 
 August, 1 85 1 . He reported that ' 'while passing through 
 the village of Tucson in the proceeding February, he had 
 observed two large pieces of meteoric iron used by the 
 
 1 The Meteoric Iron of Tucson, Mineralogical Magazine, 9, No. 41, p. 16. 
 
NATIVE; EI^MSNTS 17 
 
 blacksmiths of the town as anvils.' 1 The blacksmiths 
 were reported as having been very persistent in not al- 
 lowing him to chip off fragments for further examination 
 stating that in a certain canon in the immediate vicinity 
 the fragments were so abundant that many samples could 
 easily be obtained. 
 
 In 1854, Professor Shepard 1 gave a brief account of 
 these meteorites, in which he states that according to in- 
 formations furnished him, they were found in a canon 
 of the Santa Rita mountains, about 25 or 30 miles south 
 of Tucson. Both were reported as being used as anvils, 
 and one was described as being of a peculiar annular 
 form. About this time also, samples were analyzed by 
 Professor Lawrence Smith 2 and others. 
 
 In 1857, Dr. Irwin, Surgeon of the United States 
 Army, found the ring meteorite in one of the streets of 
 Tucson and took possession of it with the intention of 
 placing it in the Smithsonian Institution. It was started 
 on its journey in 1860, and after traveling to Guaymas, 
 Mexico, then to San Francisco, finally reached Washing- 
 ton in 1863, by way of the Isthmus of Panama. Dr. Irwin 
 states that it was considered by the inhabitants of Tucson 
 at that time to have come from the ' 'Catarina' ' mountains, 
 and further, that it was believed a meteoric shower had 
 taken place there about 200 years ago. 3 It would seem, 
 however, as explained by Mr. Fletcher, that the term 
 "Catarina" was loosely applied, and that Dr. Irwin was 
 thus misinformed as to the real locality. 
 
 1 Am. Jour. Sci., 2d series, 18, p. 369. 
 
 2 Am. Tour. Sci., 2d series, 19, p. 161. 
 
 8 Smithsonian Report, 1863, and Fletcher : Min. Mag., 9, No. 41. 
 
l8 THE MINERALOGY OF ARIZONA 
 
 The dimensions of the annular meteorite, or Irwin 
 Iron, as it is sometimes called, still to be found in the 
 Museum at Washington, are given by Whitney, as 
 follows : 
 
 Greatest exterior diameter 49 in. 
 
 Least exterior diameter 38 in. 
 
 Greatest width of central opening 26^ in. 
 
 Least width of central opening 23 in. 
 
 Greatest thickness at right angles to plane of 
 
 ring 10 in . 
 
 Width of thickest part of ring 17 j in. 
 
 Width of narrowest part 2^ in. 
 
 Weight 1,400 Ibs. 
 
 This fragment is further known as the Tucson Meteor- 
 ite, the Signet, the Ring Meteorite, the Ainsa, the 
 Muchacho, etc. 
 
 The other fragment from Tucson was of the shape of 
 an elongated flattened slab. Its length was 49 inches, 
 average breadth 18 inches, and varying in thickness from 
 2 to 5 inches. Its weight was determined to be 632 Ibs. 1 
 It was taken possession of by Gen. Carleton and sent to 
 San Francisco. Hence it is known in Mineralogical liter- 
 ature as the Carleton Meteorite. 
 
 As a result of the investigations on polished surfaces 
 of these two meteoric masses, it is generally believed 
 that they were portions of the same mass, or at least both 
 were members of the same meteoric shower. 
 
 The chemical composition is illustrated by the follow- 
 ing analyses : 2 
 
 1 Proc. Cal. Ac. Nat. Sci., 1863, 3, pt. i, p. 49. 
 
 2 Quoted from Min. Mag., 9, No. 41. 
 
NATIVE ELEMENTS IQ 
 
 Smith Genth Brush 
 
 Per cent. Per cent. Per cent. 
 
 Fe 85.54 83.47 81.65 
 
 Ni 8.55 9.44 9-17 
 
 Co 0.61 0.42 0.44 
 
 Cu 0.03 0.008 0.08 
 
 P 0.12 o.io 0.49 
 
 A1 2 O 3 Trace Trace Trace 
 
 CaO 0.46 1.16 
 
 MgO 2.04 2.59 243 
 
 Cr 2 O 3 0.21 
 
 SiO 2 3.02 2.89 2.63 
 
 From these analyses it appears that the meteorites are 
 mostly nickel iron, with small quantities of olivine, 
 schreibersite and chromite. 
 
 An excellent model of the ring meteorite has recently 
 (July, 1907), been received from Washington, and can 
 be seen at the Museum of the University of Arizona. 
 
 Canon Diablo Iron. One of the most famous occur- 
 rences of meteoric iron in the world is that of the Canon 
 Diablo iron, found in the immediate vicinity of a slight 
 elevation, variously known as Crater Mountain, Coon 
 Butte, and Meteor Mountain. It is located in the 
 plateau region of Arizona, about twelve miles from the 
 Santa Fe station, known as Canon Diablo, and thirty-five 
 miles from Flagstaff. The iron is found in fragments 
 scattered on the surface of the ground in sizes varying 
 from that of a bean to masses weighing over one hundred 
 pounds. In all it is said that nearly twenty tons of the 
 material have been gathered and distributed to various 
 museums and private collections in all parts of the world. 
 Occasionally, as many as thirty fragments may be picked 
 
2O THE MINERALOGY OF ARIZONA 
 
 up by one person in a single day. They are especially 
 easy to find immediately after a rain, for then the loose 
 dirt is washed away from the fragments, rendering them 
 more easily visible. The writer visited the locality in 
 1906, and a search of twenty minutes only was necessary 
 in order to secure a specimen about two inches in length. 
 At the station of Canon Diablo there were nine large 
 fragments awaiting shipment, weighing from 75 to 150 
 Ibs. each, besides several large boxes containing smaller 
 pieces. 
 
 The locality is especially interesting to the geologist, 
 not only on account of the meteoric masses found there, 
 but because of the interesting question as to the origin 
 of the elevation apparently so intimately connected with 
 them. The mountain or hill contains on its summit a 
 well defined depression or crater which has a maximum 
 depth of 600 feet, and a width of 3,500 feet. The walls 
 of the crater, which are quite precipitous in places, are 
 formed by the same strata of sandstone and limestone as 
 those which make up the floor of the plateau. These are 
 tilted and slope away from the cavity, just as one would ex- 
 pect, had the strata been uplifted by some great force act- 
 ing from below, followed by a collapse of the central mass- 
 There is, however, an entire absence of fused material or 
 volcanic ejectamenta, and no evidence of metamorphism 
 of an igneous character having taken place within a 
 radius of twelve miles. In this respect, the crater is un- 
 like those usually found in a volcanic region. This fact, 
 together with the extraordinary occurrence of meteoric 
 
NATIVE ELEMENTS 21 
 
 iron, has led to the supposition by many that the depres- 
 sion was not caused by volcanic action, but by the impact 
 of an immense meteor nearly one-half mile in diameter, 
 which on striking the earth buried itself and formed up- 
 turned edges very much as when a bullet falls into soft 
 mud. Others look upon the phenomenon as having been 
 caused by a volcanic explosion which lacked energy suf- 
 ficient to bring the fused mass to the surface. The ex- 
 plosion was followed, it is supposed, by a complete ces- 
 sation of vulcanism. This seems to be the better explan- 
 ation, since it can easily be seen that such an explosion 
 might occur on the border of a region of such extreme 
 volcanic activity as was able to produce the most lofty 
 mountain in Arizona as well as more than a hundred 
 small cinder cones. 1 Dr. Chamberlin of Chicago Univer- 
 sity looks upon the formation as having been produced 
 by an explosion, due to the vaporization of underground 
 water, brought about by the near approach of molten 
 rock. 
 
 Further, there seems to be some doubt on the part of 
 some regarding the meteoric origin of the iron frag- 
 ments. Dr. Karl Hintze, in his Handbuch der Min- 
 eralogie, refers to the Canon Diablo irons as possi- 
 bly of terrestrial origin (" terrestrisch vielleicht " ) . 
 H. Moissan also makes the statement, " Ce fer 
 de Canon Diablo a e*te regarde par certains ge*ol- 
 ogues comme une meteorite, et par d'autres comme 
 
 1 Coon Mountain and its Crater, D. M. Barringer : Proc. Ac. Nat. Sc., Dec., 
 1905 ; Coon Butte, Arizona, B. C. Tilgham ; Ibid, Coon Mountain Crater, F. N. 
 Guild : Science, 26, p. 24. 
 
22 THE MINERALOGY OF ARIZONA 
 
 un fer terrestre analogue au fer d'Ovifak decouvert au 
 Greenland par Nordenskiold." l 
 
 The composition of the iron, as shown by the follow- 
 ing analyses made by H. Moisson, of Paris, varies greatly 
 in different parts of the same fragment. 
 
 1234 
 
 Per cent. Per cent. Per cent. Per cent. 
 
 Iron 91.12 95.06 91.09 92.08 
 
 Nickel 3.07 5.07 i. 08 7.05 
 
 Small quantities of silica, magnesia and phosphorus 
 are also reported. 
 
 The Weaver Meteorite. This large meteoric fragment 
 was found in the Weaver mountains, near Wickenberg, 
 Maricopa Co., in 1898. It is of especial interest on 
 account of its high percentage of nickel and cobalt and 
 its uniformity of texture, etching solutions failing to 
 bring out any very characteristic figures. The locality 
 in which it was found has yielded but one fragment of 
 rounded outline, weighing about eighty pounds. Two 
 analyses of this meteorite have been made in the writer's 
 laboratory by Mr. W. B. Alexander and Mr. F. Hawley. 
 The results are shown in the table below. 
 
 Alexander Hawley 
 
 Iron 79.60 81.81 
 
 Nickel 18.80 16.63 
 
 Cobalt i. 60 1.18 
 
 Carbon, manganese, and phosphorus. . Traces Traces 
 
 Specific gravity 7.9818 7.987 
 
 The meteorite was furthur investigated spectroscopi- 
 cally for helium, but with negative results. 
 
 i Trait^ de Chimie Mineral, Vol. 2, p. 192. 
 
II. SULPHIDES, ARSENIDES, ETC. 
 
 Tetradymite, Bi 2 (Te,S) 3 
 
 This is a soft, steel-gray mineral consisting of bismuth, 
 sulphur and tellurium. It has been found in small quan- 
 tities in the Montgomery Mine. 1 It also occcurs in 
 quartz associated with pyrite near Bradshaw City, 
 Yavapai Co., where it is found slightly altered to a 
 brownish decomposition product, probably Montanite, 
 the bismuth tellurate. 2 This mineral frequently contains 
 gold, and is often associated with that metal in the tel- 
 luride ores of Colorado and California. 
 
 Molybdenite, MoS 2 
 
 This is a soft mineral, closely resembling graphite in 
 its general appearance. It contains sulphur and the 
 semi-metal molybdenum. The mineral seems to be quite 
 widely distributed in Arizona, where it is frequently 
 found as an accessory in many of the copper, lead and 
 silver deposits. In the Morenci fissure vein, it occurs 
 in primary association with pyrite, chalcopyrite and zinc 
 blende. It is also present in the ordinary smelting ore 
 of the district, as shown by chemical analysis. 3 
 
 In the Santa Rita mountains, 30 miles south of 
 Tucson, it is found in the form of small foliated aggre- 
 
 1 Dana : Text Book of Mineralogy, p. 285. 
 
 2 Genth : Am. Jour. Sci., 3d series, 40, p. 114. 
 
 3 L,indgren : U. S. G. S., PP. No. 43, p. 107. 
 
24 THE; MINERALOGY OF ARIZONA 
 
 gates in pure milky quartz, where it alters to molybdite, 
 or the hydrous ferric molybdate. 1 
 
 In the Silver Bell district, northwest of Tucson, it 
 occurs in large masses, sometimes of three or four pounds 
 weight, consisting of crystalline aggregates, and asso- 
 ciated in the same hand specimen, with quartz, galena, 
 pyrite and chalcopyrite. It has further been observed 
 associated with secondary sulphides of copper in the 
 mines at Johnson, near Cochise. 
 
 Domeykite, Cu 3 As 
 
 This is a rare arsenide of copper usually presenting a 
 tin-white lustre, easily tarnishing to a dull bronze. It 
 is very tough and somewhat malleable under the ham- 
 mer. Good specimens of this mineral have been received 
 at the University of Arizona from Cochise County, but 
 no data regarding the associations and mode of occur- 
 rence have been obtained. 
 
 Argentite, Silver Glance, Ag 2 S 
 
 This is a dark lead-gray mineral resembling copper 
 glance but easily distinguished from it by its being more 
 easily cut with a knife. It has been reported from the 
 Silver King mine, and is occasionally met with as an ac- 
 cessory in other metalliferous deposits of the State. 
 It is further a quite constant constituent in argen- 
 tiferous galena but is so intimately mixed with it as to 
 escape observation. 
 
 i Guild : Am. Jour. Sci., 23, p. 455. 
 
SULPHIDES, ARSENIDES, ETC. 2$ 
 
 Hessite, Ag 2 Te 
 
 This is a rare telluride of silver with nearly always 
 some gold. It has been reported from the West Side 
 mine, Tombstone. 1 
 
 Galena, Lead Glance, PbS 
 
 This well known mineral is widely distributed in the 
 State, as is shown by the official reports on the pro- 
 duction of lead from the different counties. In all about 
 five millions of pounds of the metal were produced in 
 1905, the greater portion of which was obtained from 
 this mineral. The following counties were represented : 
 Cochise, Graham, Mohave, Pima, Final, Santa Cruz, 
 Yavapai and Yuma. 2 The frequent occurrence of this 
 mineral with gold has been mentioned by W. P. Blake. 3 
 It is frequently found associated with the oxidized 
 products of lead such asanglesite, cerussite, etc., and also 
 with wulfenite, vanadinite, decloizite, etc. The localities 
 and different modes of occurrence are too numerous to 
 mention. 
 
 Chalcocite, Copper Glance, Cu 2 S 
 
 This also is a well known mineral usually found in the 
 zone of secondary sulphide enrichment where percolating 
 copper solutions have come in contact with lean sulphides. 
 It is especially abundant in the Clifton-Morenci dis- 
 trict where it is found in disseminated grains and seams 
 in altered porphyries. It is not a primary mineral here as 
 
 1 Hintze : Mineralogie, p. 453. 
 
 2 Mineral Resources, 1905. p. 138. 
 
 3 Rep. to Gov. of Ariz., 1899, p. 105. 
 
26 THE) MINERALOGY OF ARIZONA 
 
 supposed by some, but has been formed by the replace- 
 ment processes taken place between grains of pyrite or 
 chalcopyrite and descending copper solutions. 1 
 
 In the Copper Queen mine at Bisbee it is only occasion- 
 ally found, where it is described as an envelope on pyrite 
 showing the first stages of a secondary enrichment 
 process. 2 
 
 Stromeyerite, Ag 2 S, Cu 2 S. 
 
 This mineral can hardly be distinguished from copper 
 glance except by chemical analysis. The essential differ- 
 ence consists in the large percentage of silver. It has 
 been observed in the Heintzelman mine, 8 and in the Silver 
 King mine, Final Co. 
 
 Sphalerite, ZnS. 
 
 This mineral is a sulphide of zinc and varies in color 
 from yellow and almost white, through orange tints to 
 black. When pure, it has a characteristic resin-like 
 luster. The darker varieties owe their color to the 
 sulphide of iron, which is present as an impurity. These 
 dark modifications are frequently called by the miners 
 black jack or mock lead ; the purer samples are referred 
 to as rosin jack. 
 
 Sphalerite has been frequently found as an accessory 
 ore in many of the mines of the State, associated 
 with argentiferous galena, pyrite and chalcopyrite. It 
 has been noted below the zone of secondary enrichment 
 in the Clifton-Morenci district, disseminated in hard 
 
 i Lindgren : U. S. G. S M PP. No. 43- 
 
 U. G. S., PP. No. 21, p. 128. 
 
 8 Dana : Text Book of Mineralogy, p. 290. 
 
SULPHIDES, ARSENIDES, ETC. 27 
 
 limestone and metamorphic rock. 1 It is found in the 
 silver-lead prospects in the San Xavier district, asso- 
 ciated with galena and other sulphides. Small quantities 
 have been reported from the copper deposits of the Hoi- 
 brook and Gardiner shafts, 2 Bisbee. In the Silver King 
 it has been observed as occurring in light sea-green 
 masses, associated with threads of native silver, which 
 sometimes cement the cleavage masses together. 3 It 
 further occurs below oxidized gold ores in the Montana 
 mine of the Oro Blanco district, Santa Cruz Co. The 
 disastrous effect of passing from free-milling gold or 
 silver ores into these basic sulphides is well known. 
 
 Zinc of commercial importance has been produced by 
 the Copper King Mines Co., operating in the Tiger dis- 
 trict of Yavapai County. 4 
 
 Alabandite, MnS 
 
 This rare sulphide is quite abundant in the lyucky 
 Cuss mine at Tombstone ; it is usually associated with 
 manganiferous limestone, in both massive forms and 
 specimens possessing good cubic cleavage. It is dull 
 black in color and can easily be recognized from the fact 
 that it gives a dark green streak or powder. 
 Cinnabar, HgS 
 
 The red sulphide of mercury is found in Yuma Co. , on 
 the properties of the Colonial Mining Co., 14 miles from 
 Ehrenberg. The ore is said to average about i}4 per 
 
 1 Ijndgren : U. S. G. S., PP. No. 43. 
 
 2 Ransome : U. S. G. S., PP. No. 21. 
 
 3 W. P. Blake : Rep. to Gov., 1899. 
 * Min. Res. of the U. S., 1905. 
 
28 THE; MINERALOGY OF ARIZONA 
 
 cent, of mercury. The same mineral has also been re- 
 ported from Yavapai County. 1 
 
 Covellite, CuS 
 
 This is an indigo blue sulphide of copper, frequently 
 met with in the Butte mining district, Montana, but very 
 rare elsewhere. It has never been found in good speci- 
 mens in Arizona, and, in fact, has been noted only in the 
 Ryerson and Montezuma mines in the Clifton- Morenci 
 districts. 2 
 
 Bornite, 3Cu 2 S.Fe 2 S 3 
 
 This beautiful sulphide of copper and iron can easily 
 be recognized from its striking iridescent tarnish, for 
 which reason it is frequently called variegated copper ore, 
 or peacock ore. The colors vary in the same hand speci- 
 men from golden yellow and greenish tints to rich brown 
 and purple. It is nearly always associated with pyrite 
 and the various sulphides of copper. 
 
 Bornite is frequently met with in the zone of sulphide 
 enrichment in the Bisbee district and in other copper 
 deposits of the State. 
 
 Chalcopyrite, Cu 2 S.Fe 2 S 8 
 
 This mineral is known as copper pyrites and can be 
 distinguished from iron pyrites which it closely resembles 
 in its inferior hardness and usually by its duller and more 
 brass-like luster. It occurs in the Copper Queen mine, 
 especially in the lower levels where frequently large 
 bodies are encountered, is less abundant in the Clifton- 
 
 1 Min. Res. of U. S., 1905, p. 398. 
 Lindgren : U. S. G. S., PP. No. 43. 
 
SULPHIDES, ARSENIDES, ETC. 2O, 
 
 Morenci district, but constitutes the chief ore in the 
 Jerome, Silver Bell, Twin Buttes, Helvetia and other 
 properties. 
 
 Chalcopyrite is probably the mineral in which the cop- 
 per in many, if not all, of the mines of the State 
 originally existed. It was probably mixed with large 
 proportions of iron pyrites, and might in most cases 
 more appropriately be called cuperiferous iron pyrites. 
 The other minerals have been derived from it by what is 
 known as metasomatic or replacement processes. This 
 goes on very much as follows : The lean sulphide, chalco- 
 pyrite or, as suggested above, iron pyrites which contain 
 a small amount of this mineral, on being exposed to the 
 action of air and water, becomes oxidized, setting free 
 among other constituents copper sulphate, which is solu- 
 ble in water. This solution descends, and coming in 
 contact with the lean sulphides below, a replacement 
 takes place by which copper is deposited in the molecule 
 and iron removed. 1 The deposit is then called an enrich- 
 ment zone, and such sulphides asbornite, chalcocite, etc., 
 result. 
 
 Pyrite, FeS 2 
 
 This mineral is so well known on account of its wide 
 distribution that no extended account of its occurrence in 
 Arizona is necessary. It is found as a microscopic ac- 
 cessory mineral in many of the igneous rocks, especially 
 the basic dikes, and as an association in the copper, lead 
 and other metalliferous deposits, including gold bearing 
 
 i See Chalcocite, where a first stage of this process is mentioned. 
 
3O THE MINERALOGY OF ARIZONA 
 
 veins. In the latter case it is not unusually present near 
 the surface, having been oxidized to limonite or hematite, 
 thus giving the rock a rusty honey-combed appearance. 
 This part of the vein material is called " free-milling, " 
 since the pyrite which originally held the gold enclosed 
 in its firm crystalline structure, has become disintegrated, 
 setting * ' free ' ' the gold which can then be easily ex- 
 tracted by well known metallurgical processes. 
 
 Schreibersite, (Fe, Ni, Co) 3 P 
 
 The mineral is a phosphide of iron with some nickel 
 and cobalt. It occurs only in meteorites, and has been 
 reported from the Canon Diablo irons. 1 
 
 Cobaltite, CoAsS 
 
 Cobalt ores, presumably of economic value, have re- 
 cently been discovered in the vicinity of Jerome. The 
 minerals have not been thoroughly investigated yet, but 
 cobaltite, associated with erythrite, or cobalt bloom, has 
 been positively identified. 2 
 
 Cohenite, Fe 8 C 
 
 As a' mineral, this compound has been found only 
 in meteoric iron. It is a carbide of iron, as the formula 
 given above indicates, and analyses from material isolated 
 from the Canon Diablo irons, have been reported by 
 Derby. 8 
 
 1 Derby : Am. Jour. Sci., 1895, 49, 107. 
 
 2 See Erythrite. 
 
 * Am. Jour. Sci., 1895, 49, 106. 
 
ID. SULPHO-SALTS, SULPHARSENITES, ETC 
 
 Bournonite, (Pb, Cu 2 ) 3 S.Sb 2 S 3 
 
 This rather rare mineral has been described by Profess- 
 or W. P. Blake as associated with pyrite, sphalerite and 
 galena at the Boggs mine, in the Big Bug district. 1 It 
 is a soft, easily fusible dark steel-gray mineral, possessing 
 the chemical composition of a sulphantimonate of lead 
 and copper. 
 
 Tetrahedrite, or Gray Copper, Cu 8 Sb 2 S 7 
 
 This is a sulphantimonite of copper with varying 
 amounts of the metal replaced by silver, lead, zinc, etc. 
 It more often accompanies silver ores than copper. In 
 Arizona it occurs in the Heintzelman mine and the Silver 
 King, Pinal Co., where assays have run as high as 3,000 
 ounces silver to the ton. 2 
 
 Pyrargyrite and Proustite, or Ruby Silver Ores 
 Ag 3 SbS 3 , and Ag 3 AsS 3 
 
 These rare minerals are the sulphantimonites and 
 sulpharsenites of silver. They have occasionally been 
 met with accompanying other silver ores in many of the 
 ore deposits of the State. (Dana.) When first taken 
 from the mine they possess a beautiful pure ruby color. 
 Unfortunately, however, on exposure to light, they 
 
 1 Am. Jour. Sci., 3d series, 39, p. 45. 
 
 2 W. P. Blake : Report of Ter. Geologist, 1909. 
 
32 THE MINERALOGY OF ARIZONA 
 
 darken and finally become dull black. The beautiful 
 masses from Mexico, preserved in the British Museum, 
 have kept their ruby aspect, having been enclosed in 
 black boxes. 
 
 Polybasite, Ag 9 SbS 6 
 
 This is another rare sulphantimonite of silver, differ- 
 ing from ruby silver, in containing a larger percentage 
 of silver. It has been observed in the Silver King mine. 
 (Dana.) 
 
IV. CHLORIDES, FLUORIDES, BROMIDES, ETC. 
 
 Halite, Common Salt, NaCl 
 
 This mineral is found dissolved in the water of all 
 streams, springs and underground sources, but ordinarily 
 in such small quantities as to be hardly perceptible except 
 by chemical analysis. It has been found in beautiful 
 transparent masses associated with thenardite, mirabilite 
 andglauberite in the Verde Valley, Yavapai Co., where it 
 appears in irregular deposits in the more abundant sul- 
 phates mentioned above. The deposit has resulted from 
 the evaporation of an inland sea or lake. 1 This mineral 
 is further found in salt springs in the upper Salt River 
 Valley. 
 
 Cerargyrite, or Horn Silver, AgCl 
 
 Horn silver, the miner's name for the chloride and 
 bromo-chloride of silver, can be easily recognized from 
 its waxy appearance, and from the fact that it can be cut 
 with a knife into thin shavings which do not fall apart. 
 It has been frequently observed in the zone of oxidation 
 in many of the silver deposits of the State. It has 
 been reported in the following districts : Tyndall, Santa 
 Cruz Co., Cerro Colorado, Black Warrior and others. 
 
 Embolite, Ag(Cl, Br) 
 
 This mineral is very similar to the one mentioned above, 
 usually occurring in greenish waxy grains, disseminated 
 
 i W. P. Blake : Am. Jour. Sci., 3d series, 39, p. 44, 
 
34 THE MINERALOGY OF ARIZONA 
 
 through the vein material. It is especially abundant in 
 the Pearce mining district. 
 
 lodobromite, Ag(Br, I) 
 
 This mineral resembles embolite in chemical composi- 
 tion, but has its chlorine replaced by iodine. The mineral 
 is extremely rare, but has been reported from the Hech- 
 man mine, near Globe, by Professor W. P. Blake. 1 It 
 appears as a bright yellow to pale greenish thin incrusta- 
 tion in veins of quartz and calcite. 
 
 lodyrite, Agl 
 
 This is another very rare mineral of silver appearing 
 in almost identical forms with the proceeding. It has 
 been found in the Cerro Colorado mines. 
 
 Fluorite, or Fluospar, CaFl 2 
 
 Fluospar is a well known mineral, occurring in a great 
 variety of colors, purple, green, pink and white being the 
 most common. It is easily recognized by its hardness and 
 octahedral cleavage, breaking up into small pieces with tri- 
 angular surfaces. It is a quite common gangue mineral 
 in metalliferous deposits, especially found associated with 
 lead ores. In the mines of the Silver Bell district, it oc- 
 curs in green cubes with barite, galena and chalcopyrite. 
 In the Castle Dome district north of Yuma, it is found 
 associated with galena, vanadinite, and minerals of silver. 
 In the Dragoon mountains it is found in small quantities 
 in very acid pegmatites associated with huebnerite. It 
 has also been observed in the coarse unmineralized gran- 
 
 i Am. Jour. Sci., 4th series, 19, p. 230. 
 
CHLORIDES, FLUORIDES, BROMIDES, ETC. 35 
 
 ites at the Laguna dam on the Colorado river. Small 
 quantities of this mineral have been produced commer- 
 cially in Arizona and have sold at prices as high as $i 1.50 
 per ton. 1 
 
 Atacamite, Cu 2 Cl(OH) 3 
 
 This mineral which is a rare hydrous chloride of cop- 
 per has been found only in very small quantities in the 
 United Verde mine, at Jerome, and in the Heintzelmann 
 mine. A similar mineral called Footeite has been de- 
 scribed from the Copper Queen mines at Bisbee. (Koenig) . 
 
 i Min. Res., 1903. 
 
V. OXIDES 
 
 Quartz, Si0 2 
 
 Quartz is the most common of minerals, occurring as 
 sand, gravel, sandstone, quartzite, flint, chalcedony, 
 agate, as constituent of granite, quartzporphyries, etc. 
 
 Sandstone. A beautiful red sandstone has been quite 
 extensively worked near Flagstaff and widely used as an 
 ornamental building stone. It is rather soft and does not 
 stand well the action of frost and moisture. 
 
 Chalcedony. This variety of quartz is wax-like in 
 appearance, translucent and of uniform color. The 
 various colors are given different names ; for example, 
 red samples are termed carnelian, green varieties prase 
 and chrysoprase. The most common color, however, is 
 a peculiar tendon-like tint, and as such the mineral is of 
 very common occurrence in Arizona. It is a secondary 
 mineral, resulting from the disintegration of rocks, 
 usually volcanic, by which an excess of free silica is 
 produced. The mineral is then deposited in the cracks 
 and other cavities of the rock, and being much harder 
 than the rock in which it occurs, endures long after the 
 main portion of the mass has suffered complete disinte- 
 gration. Thus it is frequently found as pebbles and 
 rounded masses in the streams and on the mesas. 
 
 Agate. This is simply a variegated chalcedony, the 
 irregularities sometimes taking the form of bands which, 
 when parallel and of alternate light and dark colors, con- 
 
OXIDES 37 
 
 stitute the onyx and sardonyx. When the variegations 
 are in the form of moss-like or dendritic growths, the 
 specimen is known as the moss-agate. The mineral is 
 formed in exactly the same manner as chalcedony, the 
 variegated tints being due to small amounts of various 
 oxides, which serve merely as coloring matter. Some of 
 the most beautiful agates are formed in lavas, which 
 when they were erupted, contained such quantities of 
 gas and water vapor, that large rounded cavities were 
 formed by their expansion when the lava cooled. As 
 described above, these cavities become filled with silicious 
 matter, which from year to year varied slightly in com- 
 position, thus giving rise to a concentric banded struc- 
 ture. Sometimes the cavity is not completely filled, in 
 which case the mineral is like a hollow shell, frequently 
 lined with the most beautiful crystals. These are called 
 geodes, and are occasionally found in the streams of 
 Arizona, where they have been washed out of the rock 
 which contained them. They are also found in place 
 embedded in what is known as the Aubrey limestone, 
 which is abundant in the northern part of the State. 
 Agates in Arizona have been described from the lavas of 
 the Tucson range of mountains, 1 and as blue gray 
 amygdules coated with opal from other portions of the 
 State. 2 
 
 Diatomaceous Earth. This is a variety of silica, per- 
 haps more accurately described under opal, which forms 
 the shell of microscopic organisms. It is deposited in 
 
 1 Guild : Am. Jour. Sc., 4th series, 20, p. 313, Plate IX. 
 
 2 Kunz : Gems, p. 130. 
 
38 THE MINERALOGY OF ARIZONA 
 
 quiet water, either lake or ocean. A snow white deposit 
 of this material, occurring in the San Pedro Valley, and 
 associated with fine volcanic ash, has been described by 
 Professor W. P. Blake. 1 Deposits of the same material 
 are also described in the Bradshaw folio of the United 
 States Geological Survey. 
 
 Petrified Wood. This form of silica or quartz is very 
 abundant in Arizona, whose specimens are justly prized 
 by museums and private collectors in all parts of the 
 world. The material is especially abundant in the re- 
 gion of the Grand Canon and extending southward along 
 the Colorado river to Yuma. The petrifaction sometimes 
 takes the form of impure silicious matter, in which the 
 exact form and structure of the wood is preserved, but 
 not in very pleasing tints. At other times the silicifica- 
 tion is in the form of chalcedony, jasper, agate, etc., giv- 
 ing rise to very striking and beautiful specimens. It is 
 remarkable that all these brilliant tints are sometimes 
 mingled in the same piece. A section of a large log 
 showing these variegated tints, weighing over 15 tons, 
 has been polished and deposited in the Museum of Nat- 
 ural History in Paris. The most highly prized specimens 
 are found in the vicinity of Holbrook and Adamana, 
 where many square miles are literally covered with 
 petrified logs, branches and small broken fragments of 
 bright colors. These have been highly prized by the 
 Indians on account of their hardness and color, and may 
 be found with other Indian relics in various parts of the 
 southwest. 
 
 i Am. In. Min. Eng., 33, 1903, 38. 
 
Fig. 2. 
 A microscopic section of petrified wood, showing the original cell structure. 
 
OXIDES 39 
 
 Geologically the petrified wood of Arizona is supposed 
 to occur in the middle Triassic beds called by Powell the 
 Shinarup group and possessing a thickness of about 1600 
 feet. The petrified wood is found throughout the entire 
 thickness. 
 
 Theory of Petrifaction. Petrifaction takes place 
 through well known processes of chemistry, by which 
 the molecules of a substance are removed one by one and 
 the molecules of another material deposited in their places. 
 It may be likened to a house originally built of brick in 
 which each brick is carefully removed one by one and 
 a block of marble put in its place until the entire house 
 is changed to marble, yet the shape of the original struc- 
 ture during the whole process in maintained. Thus when 
 a forest becomes buried and subjected to the action of 
 silicious waters, usually hot, a particle of wood decays and 
 a molecule of silica is moulded into its place, the process 
 being carried on with such delicacy that the cells, annu- 
 lar rings, bark, knots and other characteristic features 
 are accurately preserved in stone. How completely and 
 delicately this replacement process has progressed may 
 be seen by the accompanying cut which is a reproduction 
 of a photomicrograph of a thin section taken across the 
 grain. Replacement processes of this nature are well 
 known in mineralogy and in fact are the chief agencies 
 at work in producing ore deposits of sufficient enrich- 
 ment to be of economic value. (See Chalcocite, p. 25.) 
 
 Jasper. Jasper occurs in a variety of colors and differs 
 from chalcedony in being more opaque and less pure. 
 
4O THE MINERALOGY OF ARIZONA 
 
 The common color is red, and in this shade it is frequently 
 found in pebbles in the streams and in angular fragments 
 on the mesas and in the mountains of the State. In 
 the Petrified Forest, as described above, it is abundant 
 as jasperized wood. 
 
 Chrysophase. Blue and bluish green copper-stained 
 chalcedony has been found in abundance near Globe. 
 ' ' The mineral occurs in small stringers in the Keystone 
 copper mine in that district. The copper ore of this 
 mine is said to be principally chrysocolla or silicate ore. 
 The chalcedony varies in color from bright to pale blue, 
 bluish green, and nearly apple-green, and is more or less 
 translucent. In some places the color occurs in curved 
 layers and varies in intensity, thus bringing out the 
 mammillary structure of chalcedony in peculiar wavy 
 markings. In other places the color approaches that of 
 chrysoprase, or resembles that seen in certain artificially 
 colored chalcedony. Mr. Wightman reports a sale of 
 probably 200 pounds of selected material during 1907 by 
 the miners at Globe. After cutting, this blue chryso- 
 prase brings locally from $3.00 to $10.00 a piece for the 
 best grades. ' ' l 
 
 Flint and Chert. These are still less pure varieties of 
 silica. They are found as pebbles in the streams, as ir- 
 regular nodules in limestone, especially in the Aubrey 
 limestone in the Grand Canon region, and in various 
 other forms. 
 
 Amethyst, or amethystine quartz is clear quartz col- 
 
 i Min. Res., U. S. G. S., 1907, p. 802. 
 
OXIDES 41 
 
 ored purple by traces of manganese. It is sometimes 
 met with in the quartz veins of the State, but in 
 such quality as to make it desirable only as museum 
 specimens. Mr. Kunz has described it as occurring in 
 cavities in the petrified wood of Arizona. 1 
 
 In the McConnico district it is found in precambrian 
 rocks, sometimes in samples of great beauty. One crys- 
 tal is reported to have been sold to Tiffany, of New 
 York City, for $59. oo. 2 
 
 Opal, Si0 2 , H 2 
 
 Common opal is similar to chalcedony in composition 
 and appearance, but is uncrystallized and contains a 
 varying amount of water. The precious varieties are 
 not found in Arizona. Semi-opal and the clear variety, 
 hyalite, are occasionally found associated with other 
 modifications of silica. Kunz has mentioned hyalite in 
 Yavapai County. 
 
 Cuprite, Cu 2 
 
 The red oxide of copper or cuprite, occurs in massive 
 varieties, resembling hematite, in crystalline modifica- 
 tions in the form of cubes, octahedrons and dodecahe- 
 drons, and in capillary incrustations of vivid red. This 
 latter variety is sometimes known as plush copper ore 
 and chalcotrichite, and the transparent variety as ruby 
 copper. Ruby copper forms beautiful specimens when 
 first taken from the mine but they soon become dulled 
 
 1 Gems, p. 116. 
 
 2 U. S. G. S., Min. Res., 1908. 
 
42 THE MINERALOGY OF ARIZONA 
 
 on exposure to light. Plush copper which is more brill- 
 iant red is hardly effected by sunlight. All of the varie- 
 ties mentioned above are frequently met with in Arizona 
 and are especially abundant in the Copper Queen mines at 
 Bisbee and in the Clifton-Morenci district. They are as- 
 sociated with native copper, hematite, limonite, chryso- 
 colla and the other secondary ores of copper. Very 
 pleasing museum specimens are obtained from the Globe 
 mines which consist of massive dark brown cuprite in 
 which are little veinlets and irregular spots of delicate 
 blue chrysocolla. 
 
 Tenorite, CuO 
 
 This is a somewhat rare mineral and is known as black 
 oxide of copper. It is found in a pulverulent condition 
 mingled with manganese dioxide and associated with 
 other oxidized material in the Copper Queen mines. It 
 is thought to be still forming in the caverns there as the 
 mineral is frequently found covering the floor of cavities 
 where it has dropped from above. 1 
 
 Ice, H 2 
 
 Except on high mountains and in the northern part of 
 the State this mineral in the solid or crystallized con- 
 dition is rare in Arizona. On the northern slopes of the 
 San Francisco mountains it is sometimes found even in 
 summer months in the well-known form of snow. In the 
 southern portion, the high mountain ranges are frequent- 
 ly covered with it during the winter, and in the valleys 
 
 i Ransome : U. S. G. S., PP. No. 21, p. 128, 
 
OXIDES 43 
 
 it is well known as frost, and as thin coverings on water 
 occasionally seen in the early morning. 
 
 Ice Caves. In the vicinity of Flagstaff there are 
 numerous small caves found in both basaltic and 
 limestone rocks. A few of these have been known 
 to contain ice throughout the year. It is the cus- 
 tom of picnic parties to visit these localities, well 
 supplied with cream and other dainties, which are 
 then well frozen by the ice thus prepared and stored 
 by nature. The writer visited one of these caves in 
 the summer of 1906. It was located on the black lava 
 flow at the base of Sunset Peak where the streams of lava 
 had evidently cooled, forming a solid crust of basalt 
 which, due to further movement of the mass beneath, had 
 broken up the lava crust into a heterogeneous mass of 
 angular blocks and fantastic shapes of such complexity as 
 to make description impossible. It most resembles an 
 ice-dam formed during the spring on many of the northern 
 rivers, except that the material is black and covered by 
 numerous small craters caused by the escape of steam 
 from beneath. In this irregular mass are numerous small 
 caves formed by the piling up of blocks of basalt as well 
 as by the recession of liquid lava leaving cavities with thin 
 dome-like roofs. In these cavities the ice has collected 
 during the spring and winter months and owing to the 
 nonconducting character of the rock, does not completely 
 thaw during the warm summer. It had been preserved 
 by nature very much as ice is stored in northern climates, 
 by packing in some nonconducting substance. In these 
 
44 THE MINERALOGY OF ARIZONA 
 
 caves the ice appears as coverings on the floors and as 
 stalactites (icicles) hanging from the ceilings. 
 
 Hematite, Fe 2 3 
 
 This well known mineral, the anhydrous oxide of iron, 
 is found everywhere and in a great variety of forms. It 
 is abundant in all mines where oxidation of sulphides has 
 taken place and is the cause of the red color of many ores, 
 minerals and soils. When well crystallized it is called 
 specular iron and frequently forms beautiful cabinet 
 specimens especially when showing an iridescent tarnish. 
 It is frequently found in Arizona as a contact mineral 
 associated with epidote and similar minerals. It is fur- 
 ther found in large beds where it can be utilized as a basic 
 flux in smelting. 
 
 Magnetite, Fe 3 4 
 
 This is the black magnetic oxide of iron, and is 
 found as a microscopic accessory in nearly all rocks. 
 From this source it finds its way into black sands and 
 similar deposits. It is further found, like hematite, 
 associated with contact minerals and in a great variety 
 of ways. In the Tucson mountains it is found as rounded 
 transported blocks, frequently pitted in a manner to re- 
 semble meteorites. 
 
 Pyrolusite, Mn0 2 
 
 The Black oxide of manganese, or pyrolusite, has been 
 noted in the Clifton-Morenci district mixed with limonite. 1 
 Samples from other localities have been received at the 
 
 i I^indgren : U. S. G. S., PP. No. 43. 
 
OXIDES 45 
 
 University of Arizona, but data regarding their mode of 
 occurrence are lacking. 
 
 Limonite, Fe 2 3 3H 2 
 
 Limonite, or the hydrous oxide of iron is very abun- 
 dant ; it is associated with oxidized ores in the Copper 
 Queen mine where, together with hematite, it is the cause 
 of the reddish color of the ores. It is frequently found 
 in mammillary and kidney shapes. In general its mode 
 of occurrence is similar to that of hematite, from which 
 it can hardly be distinguished except by chemical means. 
 
VI. OXYGEN SALTS 
 
 (i). CARBONATES 
 
 Calcite, CaC0 3 
 
 The various modifications of calcite are found in nearly 
 every mountain range of the State and have frequently 
 been described in geological literature. 
 
 Limestone. This well known rock or mineral varies 
 greatly in composition and appearance in different parts of 
 the State. In many places especially in the vicinity of 
 the Grand Canon, it is very impure containing often large 
 quantities of both silica and magnesia. The silica is 
 sometimes in the form of nodules and geodes and some- 
 times as fine sand or silt intimately mixed with the car- 
 bonate. The magnesium is always in the form of mag- 
 nesium carbonate. The following analyses made by the 
 writer on samples obtained in the vicinity of Flagstaff 
 will give an idea of its composition. In geological litera- 
 ture the formation is known as the Aubrey Limestone. 
 
 No i No 2 No 3 
 
 Per cent. Per cent. Per cent. 
 
 Silica 34.10 17.00 72.21 
 
 Iron and alumina 1.60 i.oo 2.91 
 
 Calcium carbonate 33. 8 r 48.20 18.60 
 
 Magnesium carbonate... 26.43 34-4 5-62 
 
 Total 95-94 100.60 99-34 
 
 It will be seen from the analyses that No. 3 at least is 
 a calcareous sandstone rather than limestone, and in fact, 
 
OXYGEN SAWS 47 
 
 all gradation may be found in this district between pure 
 sandstone on the one side and pure limestone on the other. 
 The formation known as the Red Walled Limestone in 
 the Grand Canon is much purer in composition. A large 
 area of this has been exposed in the vicinity of Flagstaff 
 through the intrusive action of some of the crystalline 
 lavas of the San Francisco mountain district. It is found 
 in direct contact with andesite on the north flank of 
 Elden Peak, about nine miles from town. It has been 
 used in the manufacture of lime, and is said to give ex- 
 cellent results. Its chemical composition is represented 
 in the table below. 
 
 Silica * . . . 0.27 
 
 Iron and alumina 1.24 
 
 Calcium carbonate 95.84 
 
 Magnesium carbonate 0.90 
 
 Alkalies 0.48 
 
 Total 98.73 
 
 An interesting case of contact metamorphism was ob- 
 served at the immediate contact of this pure limestone or 
 marble with the crystalline andesite. Here the lime- 
 stone has become very fine grained and taken on the ap- 
 pearance of lithographic stone. The alteration is plainly 
 due to the influence of the igneous mass by which the 
 marble or limestone has become both silicified and dolo- 
 mitized. The chemical reactions which have taken place 
 in this transformation may be inferred from the following 
 table, which contains the analysis of a sample taken about 
 five feet from the contact. 
 
48 THE MINERALOGY OF ARIZONA 
 
 Per cent. 
 
 Silica 19.41 
 
 Iron oxide 2.02 
 
 Alumina 8.82 
 
 Calcium carbonate 46.30 
 
 Magnesium carbonate 25.43 
 
 Total 101.98 
 
 Marble. Marble or crystallized limestone has fre- 
 quently been used in Arizona for building purposes. The 
 local demand, however, is very slight, and freight rates 
 are such that it cannot be transported great distances. 
 Samples sent to the University of Arizona, from various 
 localities, seem to show that it is abundant and frequently 
 of very pleasing color. 
 
 Onyx Marble. This beautiful stone, more frequently 
 known as Mexican Onyx, has been found in Arizona in 
 tints and variegated effects equal in every respect to the 
 Mexican product. Mineralogically it may be considered 
 as stratified and variegated calcite or aragonite, the bands 
 and irregular coloring effects being caused by the arrange- 
 ment of such foreign pigments as iron oxide in various 
 stages of oxidation and hydration. The most important 
 locality in Arizona is near Mayers about 26 miles from 
 Prescott. The deposit is approximately twenty acres in 
 extent and the workable material is described as occur- 
 ring in bowlders containing from two to thirty cubic feet. 1 
 Other localities are Greaterville, Kirkland Valley, and 
 Oak Creek. 
 
 Caliche. This is a word of Spanish origin loosely em- 
 
 i W. P. Blake : Rep. to Gov., 1899. 
 
OXYGEN SAI/TS 49 
 
 ployed by the Mexicans and others in the south-western 
 United States and Mexico to designate almost any non- 
 crystalline crust. It was perhaps first used by the Chil- 
 lians who applied it to the soluble saline crusts of their 
 country which consisted mostly of crude nitre and other 
 soluble constituents. In some parts of California the term 
 is still used in a similar manner, perhaps with particular 
 reference to the top coatings. 1 In Arizona the term is 
 usually applied to a calcareous deposit of varying hard- 
 ness found to exist in many soils and gravels. It results 
 from the evaporation of meteoric water in situ, and of 
 water brought down from the mountains and distributed 
 throughout the valley in the form of underground streams 
 and reservoirs. The calcareous matter owes its ultimate 
 origin to the decomposition, through the influence of 
 dilute solutions of carbonic acid, of complex calcium sili- 
 cates of the soil and rocks. The following reaction is 
 given as an illustration of this decomposition : 
 
 Lime Feldspar + Alkali Feldspar -f- Carbonic Acid = 
 CaAl 2 Si 2 8 KAlSi 3 8 H 2 CO 3 
 
 Calcite (caliche) -f- Muscovite (sericite) -f Quartz. 
 CaC0 3 H 2 KAl 3 Si 3 12 2SiO 2 
 
 The reaction f urthur explains the presence of alkali in 
 the soil, since the continued action of CO 2 , or H 2 CO 3 , 
 would convert the muscovite into K 2 CO 3 and kaolin. 
 The two constituents kaolin and alkali may also be 
 formed direct from the feldspar as shown by the follow- 
 ing reaction : 
 
 1 Bailey : The Saline Deposits of Cal., Bui. No. 24, Cal. State Min. Bureau. 
 
50 TH MINERALOGY OF ARIZONA 
 
 Ortlioclase + Water -f- Carbon Dioxide 
 6KAlSi 3 8 6H 2 
 
 Kaolin -f Alkali -f Silica. 
 3H 4 A.l 2 Si s 9 3K 2 C0 3 i2SiO 2 . 
 
 The alkali is not found to any extent in the caliche, since 
 its great solubility compels it to remain mostly in the un- 
 derground waters. The kaolin, or clay, and the silica rep- 
 resented in the above reaction are always present in large 
 quantities. The muscovite then is only an intermediate 
 product, easily seen in decomposing rocks by means of the 
 microscope, but later altering into kaolin or clay. As may 
 easily be inferred, caliche is a deposit occurring only in 
 arid countries where evaporation is rapid and circulation 
 of at least surface waters slow and incomplete. It is 
 therefore abundant in Arizona and in arid portions of 
 California and Mexico. In appearance it is a light buff 
 shading to white, and seems to be made up of the ordi- 
 nary constituents of the soil such as silt, sand, gravel and 
 small pebbles firmly cemented together by calcium car- 
 bonate. Occasionally it is faintly stratified, the layers 
 being due to successive depositions from solution rather 
 than sedimentation. As a deposit in ordinary soils it is 
 always formed beneath the surface ; where erosion has 
 not taken place, there are a few inches to several feet of 
 earth on top. Its occurrence, however, is not limited to 
 within a few feet of the surface ; it is sometimes found in 
 layers of varying thickness alternating with loose sand or 
 gravel to a depth of seventy-five feet or more. The deeper 
 layers differ somewhat in character from those near the sur- 
 face. These usually consist of coarser particles of gravel 
 
OXYGEN SALTS 51 
 
 and pebbles and of even small bowlders cemented by a 
 more crystalline calcium carbonate into a mass of such hard- 
 ness that a well can be sunk into it only with the greatest 
 difficulty. Indeed, it is sometimes necessary to resort to 
 the use of blasting powder. The spaces between the 
 pebbles are lined with drusy scalenohedral crystals of 
 calcite and even well formed geodic cavities are some- 
 times observed. Evidently the deposition here took place 
 under more uniform and deeper seated conditions than 
 those which gave rise to the finer grained amorphous 
 surface deposits. The deposit is not merely local in 
 character, but many hundreds of square miles are ren- 
 dered useless for agricultural purposes by its presence. 
 
 As previously stated, it would seem that the two modi- 
 fications of this deposit described above owe their origin 
 to two closely related phenomena : (i), the layers near 
 the surface, to the evaporation of meteoric waters in situ ; 
 (2), the deep-seated layers, to evaporation of waters 
 brought up by capillary attraction to-some definite position 
 which depends upon local conditions, such as fineness of 
 material, pressure, etc. Of course it can easily be seen that 
 where underground waters exist near the surface the 
 top layers might be formed in the way last mentioned. 
 Then evaporation at depth would not take place. Again, 
 in places where there is no underground water at reason- 
 able depths, only the first mentioned cause would be oper- 
 ative. In either case the deposition takes place beneath 
 the surface and never precisely upon it. The reason for 
 this is to be found in the climatic conditions of the South- 
 west. Immediately after a rain the sun quickly reap- 
 
52 THE MINERALOGY OF ARIZONA 
 
 pears, rapidly drying the surface of the ground and thus 
 preventing furthur action of capillary attraction. Iftie 
 earth becoming like a dry sponge is unable to soak up 
 moisture from below. The depth to which this superficial 
 drying takes place depends upon local conditions such as 
 texture of the soil, vegetation and other features. The 
 remaining meteoric water is now brought up by capillary 
 attraction to the point where evaporation begins and 
 capillary attraction ends. This action continues until all 
 of the water is evaporated, is repeated after the next 
 rain, thus giving rise to faint stratifications, until finally 
 a deposit of considerable thickness is formed. 
 
 The deposition taking place through the evaporation of 
 underground waters may progress at any depth, though 
 with less rapidity as the depth increases. The exact 
 position in which the deposit is forming during any 
 series of years depends, first, upon the height of the 
 underground water, and second, upon the distance 
 through which capillary attraction is able to act under 
 the existing conditions of porosity, pressure, or other de- 
 termining agents. Thus, if the underground water at a 
 certain time is found at a depth of say eighty-five feet, 
 the calcareous deposit may actually form at that time at 
 a depth of seventy-five feet or more. Cavities are 
 actually found at this depth incompletely filled with mi- 
 nute crystals, a fact which suggests that the deposition is 
 still going on. 
 
 The explanation of the alternate layers of calcareous 
 material is to be sought in the possibility of the under- 
 ground waters having occupied higher levels in former 
 
OXYGEN SALTS 53 
 
 periods of time. The Tucson Valley, for example, is 
 filled with debris contributed by the high surrounding 
 mountains. All of this material was at one time on the 
 slopes and mountain tops of these ranges. Their alti- 
 tude, then, must have been a few thousand feet higher 
 than the present time. As is well known this would 
 have had the effect of greatly increasing the annual pre- 
 cipitation which in due course would have greatly aug- 
 mented the quantity of underground water. Regarding 
 the outlet of the underground water there is at present 
 but little known, but it is very probable that erosion and 
 the solvent action of water has had the effect of decreas- 
 ing its elevation. Thus it seems quite evident from well 
 established facts of geology that the underground water 
 of this valley, occupied in former periods of time con- 
 siderable higher levels. Evaporations at points slightly 
 above these surfaces, as described above, would ac- 
 count for the repetition of the caliche beds. 
 
 Caliche, as the term is used in Arizona, was first fully 
 described in scientific literature by Professor W. P. 
 Blake, 1 who explained its origin as entirely through 
 evaporation of underground waters brought up from be- 
 low by capillary attraction. Dissenting from this view, 
 Professor R. H. Forbes holds that all of these deposits, 
 even the deep-seated ones are formed by the evaporation 
 of rain water which has percolated to a depth of three or 
 four feet, decomposing the constituents of the soil 
 through the action of carbon dioxide. The calcareous 
 
 i The Caliche of Southern Arizona: Trans. Am. In. Min. Eng., 31, 1901, 
 p. 220. 
 
54 THE MINERALOGY OF ARIZONA 
 
 material thus formed is left behind in the soil on evapor- 
 ation of the water, a process which is repeated until a 
 limy hardpan is formed. "The different layers formed 
 at different depths below the surface mark the various 
 levels which for geological reasons remained constant for 
 a long enough period of time to permit the formation of 
 a layer of caliche just below the surface of that time." 1 
 
 Professor C. F. Tolman would confine the term caliche 
 to the amorphous surface crusts and not the crystalline 
 cements of the desert gravels. "This cement," he states, 
 * ' is primarily due to the fact that these basins are practi- 
 cally undrained. The deeper cement, moreover, may be 
 largely recrystallized crusts, and without direct relation 
 to any change in climate or water level." 2 Professor 
 Tolman also calls attention to the probability of the 
 Paleozoic limestones being an original source of much of 
 the calcareous material. 3 
 
 Siderite, FeC0 3 
 
 This mineral, sometimes known as spathic iron, is fre- 
 quently developed in Arizona as an alteration product 
 near limestone especially where sulphides of iron are ox- 
 idizing. In the Tucson mountains it has been observed 
 as a decomposition product of the ferromagnesian constit- 
 uents of basic lavas, in which it is deposited in amygda- 
 loidal cavities and cracks together with chalcedony, cal- 
 cite and agate. 
 
 1 Quoted in Underground Waters of Salt River Valley, U. S. G. S., W. S. P., 
 No. 136, p. no. 
 
 2 Manuscript. 
 
 * Pub. 113, Carnegie Inst. of Wash., 73. 
 
OXYGEN SALTS 55 
 
 Rhodochrosite, MnC0 3 
 
 So far as the writer knows, this mineral in a pure con- 
 dition has not been reported from Arizona. A manganif- 
 erous limestone, however, is found in the Tombstone 
 district and on decomposition yields manganese oxide 
 containing silver. 1 
 
 Cerussite, PbC0 3 
 
 The carbonate of lead, a heavy and when pure a white 
 or transparent mineral, is frequently met with in the lead 
 and silver mines of the State as an alteration product of 
 galena. The galena first oxidizes to the sulphate or angle- 
 site, and then coming in contact with solutions containing 
 carbonates a substitution takes place by which the sul- 
 phate radical is removed and the carbonate radical in- 
 stalled. A crystallographic study has been made by 
 Pirsson on samples from the Red Cloud mine. 2 In the 
 Bisbee district it is found in Hendricks Gulch associated 
 with limestone. Here it occurs as an impure friable mass 
 which in mining breaks up into fine sand. Hence this 
 variety is sometimes known as cerussite sand. 
 Azurite, 2CuC0 3 .Cu(OH) 2 ,and Malachite, CuC0 3 .Cu(OH) 2 
 
 The blue and green carbonate are abundant in Arizona 
 and have been so frequently mentioned in the description 
 of mining districts that little space will be devoted to them 
 here. The two minerals are nearly always associated 
 with each other even in the same hand specimen, some- 
 times so intricately mingled in delicate wavy forms as to 
 yield very striking and beautiful effects when polished. 
 
 1 W. P. Blake : Rep. to Gov., 1899. 
 
 2 Am. Jour. Sc., 42, p. 405. 
 
56 THE MINERALOGY OF ARIZONA 
 
 The crystalline varieties of azurite sometimes develops in 
 aggregates of rounded bunches, arranged in such a man- 
 ner as closely to resemble clusters of grapes. The green 
 carbonate more often appears as silky radiating tufts or 
 incrustations on botryoidal surfaces, giving the appear- 
 ance of green plush. These beautiful forms are found 
 as the lining of caves or small cavities. Here also are 
 frequently developed stalactites containing both minerals 
 in concentric layers. Cross sections of these when pol- 
 ished show concentric wavy rings of blue and green car- 
 bonates. Dr. G. F. Kunz has applied the name azur- 
 malachite to such samples when employed as a gem. 
 
 These two minerals are always secondary and are never 
 found at great depths. They result from the oxidation 
 of the various sulphides of copper by which action the 
 soluble sulphates are formed, which on coming in contact 
 with limestone or carbonated waters, react to form the 
 carbonates. These are then deposited from solution in 
 the delicate forms described above. 
 
 Aurichalcite, 2(Zn, Cu)C0 3 .3(Zn, Cu)(OH) 2 
 
 This rare mineral occurs in pale green and bluish 
 flakes. It has been reported from the Copper Queen 
 mine at Bisbee and from theCatalina mountains. (Dana). 
 
 (2). SILICATES 
 
 The Feldspars 
 
 Orthoclase, KAlSi 3 8 . This is a rock-forming mineral, 
 and as a constituent of granite and the corresponding 
 
OXYGEN SALTS 57 
 
 acid eruptives, such as rhyolites, felsites, and quartz 
 porphyries, is found almost everywhere in the State. 
 In this mode of occurrence it develops in crystals varying 
 from microscopic size to crystals an inch in length. In 
 pegmatites, or the light colored veins which are nearly 
 always found crossing granites and similar rocks, it is 
 found associated with quartz and sometimes developed in 
 large masses of pure material. In the pegmatites of 
 southern California masses of this kind are frequently 
 found weighing more than 75 pounds and possessing 
 uniform cleavage and structure. Good crystals are fre- 
 quently found ten inches in length. In Arizona there 
 are no unusual deposits of this mineral. A few good 
 crystals have been found in the pegmatites of the Catalina 
 mountains, near Tucson, and good white masses may be 
 observed in many other localities. The Rincon mountains 
 have yielded rather fine samples of typical pegmatite. 
 
 Microcline. This mineral, which has the same chemi- 
 cal composition as orthoclase, with slightly different 
 crystalline structure, has been observed as a microscopic 
 constituent in the tourmaline aplites found in the vicinity 
 of Oracle, in the Catalina mountains. 
 
 Plagioclases The plagioclase feldspars differ from 
 orthoclase in composition and crystallization. Chemically 
 they are isomorphous mixtures of albite, NaAlSi 3 O 8 , and 
 anorthite, CaAl 2 Si 2 O 8 , different proportions of these two 
 molecules giving rise to the rather arbitrary varieties, 
 oligoclase, andesine, loboradorite and bytownite. They 
 are all rock-forming minerals and are found in diorites, 
 
58 TH MINERALOGY OF ARIZONA 
 
 gabbros, and their eruptive equivalents, andesites and 
 basalts. Andesites are probably the most common erup- 
 tive in the Territory, and as constituents of these the 
 plagioclases or triclinic feldspars are very abundant. 
 
 Pyroxene 
 
 Pyroxene, the common variety of which is augite, is a 
 complex silicate of calcium, magnesium, iron, etc. It is 
 a rock-forming mineral, and is abundant in Arizona as a 
 constituent of andesites, basalts and other rocks. 
 
 Amphibole 
 
 This mineral is similar to pyroxene in its chemical 
 composition and variations. L,ike pyroxene, it is very 
 abundant everywhere as a rock-forming constituent of 
 granites, andesites, dike rocks and metamorphic schists. 
 It is a constituent of the more acid and intermediate rocks, 
 while pyroxene usually indicates a more basic magma. 
 Actinolite and tremolite are the light colored varieties, 
 and are frequently found as constituents of the crystal- 
 line schists. A manganiferous variety, exact locality un- 
 known, has been analyzed by Mr. Fred. Hawley, a 
 student at the University of Arizona, with the following 
 results : 
 
 Per cent. 
 
 Silica 49-30 
 
 Ferrous oxide 15.14 
 
 Alumina 3.10 
 
 Manganese oxide 6.39 
 
 Calcium oxide 23.61 
 
 Magnesia o. 14 
 
 Undetermined 2.32 
 
 Total loo.oo 
 
OXYGEN SAI/TS 59 
 
 The mineral is dark brown with columnar divergent 
 structure. The above analysis would place the mineral 
 as near dannemorite. 
 
 Garnet 
 
 Garnet is a complex silicate of calcium and aluminium 
 in which calcium is frequently replaced by more or less 
 iron and magnesium, and the aluminium by chromium 
 and iron. It varies in color from white to black, red, 
 yellow, green and brown shades being the most common. 
 
 Garnetiferous Sand. Garnet is a frequent accessory in 
 schistose and granitic rocks. These are yielded up by the 
 rock on disintegration and owing to their ability to resist 
 erosion and corrosion collect in the eddies of the stream 
 together with black sand or magnetite. Samples illus- 
 trating this mode of occurrence have been collected from 
 the streams of the Catalina mountains which on analysis 
 are found to correspond to the manganiferous variety or 
 spessartite. 
 
 Precious Garnet. In the exteme northern part of the 
 State the Moki Indians and others bring into the 
 towns large quantities of loose garnets many of which are 
 cut and show a beautiful dark ruby tint. They are 
 known among gem dealers as the Arizona rubies and are 
 without doubt the finest garnets in the United States. 
 They are picked up in gravel deposits and around 
 ant-hills where these industrious workers have brought 
 them from the surrounding country. The associated 
 minerals are peridot, pyroxene, magnetite and similar 
 minerals. The gem has never been found in place but 
 
60 THE) MINERALOGY OF ARIZONA 
 
 owing to its associations, one is authorized in assuming 
 that it was developed in some of the ultra-basic rocks such 
 as the peridotites. They are always found in well round- 
 ed and polished pebbles varying from a few millimeters to 
 two centimeters in diameter. The latter, however, are 
 never of gem quality. The average size for cutting is 
 about one carat ; two carat stones are abundant but the 
 three carat size is very scarce. The smooth polished sur- 
 faces of these fragments seems to be due to wind erosion 
 rather than stream. (See Mineral Resources, 1908.) The 
 index of refraction of these gems as determined with 
 sodium light on a Fuess instrument is 1.7500. This 
 corresponds to the variety pyrope. 
 
 Yellow garnet, or variety containing larger quantities 
 of lime, has frequently been received at the University of 
 Arizona for identification, and a fine large crystal from 
 Gila Canon has been described by Mr. Kunz. 1 The min- 
 eralogical name for this variety is Grossularite. 
 
 Massive Garnet. This variety of garnet is very com- 
 mon in many of the mining districts of the State hav- 
 ing been developed by contact action between limestone 
 and igneous intrusion. This modification varies in color 
 from nearly black to light yellow according to the acidity 
 of the magma. Near the contact with basic eruptives 
 the dark colored varieties are formed. It is found in the 
 Clifton-Morenci district in altered limestone in the form 
 of andradite, or common iron garnet, yellow to dark 
 brown in color and of a resinous luster. It is further 
 found in the same locality intergrown with magnetite, 
 
 1 Gems, p. 79. 
 
OXYGEN SAVTS 6l 
 
 pyrite, zinc blende and chalcopyrite. 1 It is is also abun- 
 dantly developed in the Silver Bell, the San Xavier, 
 Washington Camp and other contact districts. 
 Chrysolite, (Mg, Fe) 2 SiO, 
 
 This is usually a yellowish green mineral consisting of 
 an isomorphous mixture of the two constituents, iron and 
 magnesium silicate. It is usually a rock-forming mineral, 
 and as such is more frequently known as olivine. It is a 
 normal constituent of basalts and most gabbros, and in 
 these varieties of rock is of very common occurrence in 
 Arizona. The crystals are usually so small as to escape 
 ordinary observation. Yet in some of the basalts of the 
 San Francisco mountains crystals are found more than 
 one-half inch in length. 
 
 Peridot. Crystals of sufficient purity and transparency 
 to be useful as a gem are known as peridot. It is found 
 in beautiful tints near Talkai, and is frequently collected, 
 together with the red garnets with which they are some- 
 times found, by the Indians and prospectors. A crystal 
 from this locality, exhibited at the World's Fair, at Port- 
 land, in 1905, after being cut, was a beautiful gem of 25% 
 carats. It was pale yellowish green and took a brilliant 
 polish. The gem variety of chrysolite is most often 
 found in the streams as worn pebbles, but is occasionally 
 found lining cavities in basaltic lavas of sufficient clear- 
 ness to be used as a gem. Like garnets, they are found 
 around ant-hills. One hill investigated by members of 
 the United States Geological Survey was found to be 
 made up of 75 per cent, of peridot grains, the remainder 
 
 ITJ. s. G. s., PP. NO. 43. 
 
62 THE MINERALOGY OF ARIZONA 
 
 being garnet, quartz, diopside, etc. They are brought 
 to the hills from the surface over an area of many square 
 feet surrounding the ant houses. 
 
 Wollastonite, CaSiO, 
 
 This is a contact mineral sometimes developed where 
 igneous rocks of intrusion come in contact with lime- 
 stone. When pure it is a white mineral of pearly luster 
 and breaking into splintery forms. Contact deposits are 
 of common occurrence in Arizona, but this mineral has 
 not been described from many localities. It has been 
 mentioned among the contact minerals in the Clifton- 
 Morenci district. 1 
 
 Willemite, Zn 2 SiO, 
 
 This anhydrous silicate of zinc is usually a light yellow 
 mineral somewhat resembling yellow garnet. It has 
 been observed in Arizona only in very small quantities 
 in the Clifton-Morenci district, on the north side of 
 Modoc mountain. It was first discovered here by Mr. 
 Boutwell, and identified by Messrs. Pirsson and Penfield, 
 of Yale. It is described as occurring in stout hexagonal 
 crystals with the usual characteristics of the mineral. 2 
 
 Dioptase, H 2 CuSi0 4 
 
 This rare, gem -like silicate of copper is found in the 
 Clifton-Morenci district, as noted by Hill. 3 The crystals 
 occur in beautiful emerald green incrustations lining 
 cavities and associated with ferruginous matter and 
 
 1 U. S. G. S., PP. No. 43, p. 124. 
 
 2 U. S. G. S., PP. No. 43. 
 
 3 Am. Jour. ScL, 3d series, 33, p. 325. 
 
OXYGEN SALTS 63 
 
 chrysocolla. It has been further reported from near 
 Riverside, by W. B. Smith. 1 
 
 Vesuvianite 
 
 This is a complex silicate containing calcium, alumin- 
 ium and a small amount of fluorine. It is frequently 
 developed in contact metamorphism together with garnet 
 and epidote. In appearance it resembles the latter min- 
 eral closely, but may be distinguished from it easily by 
 the absence of iron ; epidote becomes magnetic on heat- 
 ing before the blowpipe, while vesuvianite does not. 
 Samples have been received at the University from the 
 vicinity of Jerome, but data regarding the mode of oc- 
 currence are lacking. It doubtless occurs in other 
 localities in the State, but has not been described or 
 else has been mistaken for other minerals which it re- 
 sembles. 
 
 Zircon, ZrSi0 4 
 
 This mineral has been noted in Arizona in the Clifton- 
 Morenci district only as a microscopic accessory in granite 
 and porphyry. 2 
 
 Topaz, (AlF) 2 Si0 4 
 
 Samples of this mineral have been received at the Uni- 
 versity from localities in the northern part of the State 
 in the form of white broken fragments, much re- 
 sembling quartz, for which it has frequently been 
 mistaken. It can be easily distinguished from that min- 
 
 1 Proc. Colo. Sci. Soc., a, p. 159. 
 
 2 Undgren : U. S. G. S., PP. No. 43, p. 102. 
 
64 THE MINERALOGY OF ARIZONA 
 
 eral, however, by its superior hardness and its cleavage. 
 The exact locality of these samples is not known. 
 
 Andalusite, Al 2 Si0 5 
 
 The silicate of aluminium known as andalusite is devel- 
 oped in slates and other sedimentary deposits through 
 the influence of both regional and contact metamorphism. 
 In rare instances it has been observed as a pyrogenic con- 
 stituent of igneous rocks. Thus in Arizona it has been 
 observed as a microscopic accessory in the granites in the 
 Globe copper district. It has been suggested that possi- 
 bly the mineral has been developed here through recrys- 
 tallization brought about by metamorphic action, and is 
 not an original constituent as it would seem. 1 
 
 Cyanite, Al 2 Si0 5 
 
 This is a pale blue bladed mineral of the same composi- 
 tion as andalusite, and though appearing quite different 
 from it, occurring in a similar manner. In a ground mass 
 consisting of quartz and mica, it is found north of Yuma 
 in the form of small stout crystals about one-half inch in 
 length. In the same locality it is further found associated 
 with dumortierite. 
 
 Epidote, HCa 2 (Al,Fe) 3 Si 3 13 
 
 This mineral is a silicate of calcium, iron and alumin- 
 ium, and can usually be easily recognized by its pecul- 
 iar yellowish green color. It is abundantly developed in 
 Arizona as the result of contact metamorphism ; hence it 
 is found associated with garnet and other products of this 
 
 1 Ransome : U. S. G. S., PP. No. 12, p. 66. 
 
OXYGEN SAI,TS 65 
 
 action in most of the mining districts. It is further formed 
 as the result of other secondary decomposition in nearly 
 all kinds of rocks, both sedimentary and volcanic. It may 
 appear as greenish incrustations on the surface of rocks 
 or as filling in minute cracks. In the Tucson mountains 
 it has been observed as a decomposition product in light 
 colored rhyolites where it appears as green blotches 
 through the specimen. Some of the spots are rather an- 
 gular and are thought to be pseudomorphs after feldspar. 
 In the same locality it is found in dark andesitic rocks, as 
 thin incrustations along the joint planes. This mineral 
 being of such wide occurrence is usually found in the 
 streams and washes as greenish pebbles, and as green 
 stains on other fragments. The association of epidote 
 and native copper has been described under Copper. 
 
 Gadolinite 
 
 This is a silicate of glucinum, iron, the rare yttrium 
 earths, and cerium. It is quite abundant in the mineral- 
 ized pegmatites of Norway and Sweden, but extremely 
 rare elsewhere. In Texas it has been found in nodular 
 masses and rough crystals of large size. In 1908 a de- 
 posit was found near Kingman, Arizona, and several tons 
 of the material have already been shipped East for the 
 extraction of rare earths employed in the preparation of 
 the well-known mantles for incandescent gas light. The 
 mineral from this locality presents the usual appearance 
 of dark brown to black glassy masses of conchoidal 
 cleavage not unlike ordinary obsidian. It has, however, 
 a very much higher density. It occurs associated with 
 
66 THE MINERALOGY OF ARIZONA 
 
 the new mineral, arizonite, in what seem to be pegma- 
 tites. Mr. Chase Palmer has made a partial analysis, 
 the results of which are given below. 1 
 
 Per cent. 
 
 SiO 2 24.41 
 
 Yttrium earths 36.86 
 
 Cerium earths 11.50 
 
 BeO 11.50 
 
 FeO 11.56 
 
 Calamine, H 2 ZnSi0 5 
 
 The hydrous silicate of zinc, or calamine, has been re- 
 ported as occurring in minute quantities on garnet rock 
 in the Shannon mine in the Clifton-Morenci districts. 2 
 Tourmaline 
 
 This is a complex silicate of boron, aluminium and sim- 
 ilar elements. As stout black hexagonal crystals, some- 
 times bent and faulted it is found in the Catalina moun- 
 tains near Oracle. It is here occasionally disseminated 
 through the mass in such a manner as to constitute a 
 typical tourmaline granite. It is not found in large 
 masses, however, and is simply a local condition along 
 the borders of the main granitic material. A microscopic 
 examination shows it to be associated with quartz, plagi- 
 oclase, orthoclase and microcline. Tourmaline seems 
 to be very widely distributed throughout the State as 
 shown by the frequent samples received for identification 
 at the University of Arizona. Among these have been 
 observed frequently fibrous and even granular modifica- 
 tions of the mineral. 
 
 1 Am. Jour. Sci., 28, 353. 
 
 * Lindgren : U. S. G. S M PP. No. 43, p in. 
 
OXYGEN SAI/TS 67 
 
 Dumortierite 
 
 This is a rare silicate of aluminium with a small per 
 cent, of boron. It is of a beautiful blue color and has fre- 
 quently been mistaken for copper minerals. It is fre- 
 quently found in the form of float or loose rounded peb- 
 bles in the vicinity of Clip, north of Yutna. It is asso- 
 ciated with rather granular quartzite-like rock highly 
 metamorphic and sometimes so intimately mixed that 
 the entire specimen appears blue. Under the microscope 
 however, thin sections show that the mass is made up of 
 fine needles and bunches of radiating crystals embedded 
 in the quartzite. The mineral shows beautiful pleocroism, 
 the color parallel to the elongation being a deep blue, 
 while the other two directions give nearly colorless and 
 pale violet. The quartz is well crystallized, appears in 
 rounded individuals with sharp contacts and contains 
 numerous gas and liquid inclusions. The gas bubble is 
 frequently found to be in motion. The mineral from 
 Clip has been analyzed by Diller 1 and Ford 2 both of whom 
 found noticeable quantities of boron oxide. These analy- 
 ses are of value since they show that the mineral is to be 
 considered as a compound containing boron and not a 
 simple silicate as formerly. The Arizona locality is of es- 
 pecial interest since here the mineral seems to be found 
 in a metamorphic rock rather than in pegmatites the 
 more usual mode. The presence of the gas inclusions 
 prove, however, that the metamorphism is of a deep-seated 
 type. 
 
 1 Am. Jour. Sci., 3d series, 37, p. 216. 
 * Am. Jour. Sci., 4th series, 14, p. 426. 
 
68 THE MINERALOGY OF ARIZONA 
 
 Mica 
 
 There are several varieties of mica varying in composi- 
 tion and appearance, but all possessing the well-known 
 cleavage and yielding elastic plates. 
 
 Muscovite. This variety is the common white mica 
 and is a frequent constituent of rocks and soils. In large 
 crystals it frequently developes in pegmatites or the white 
 vein-like formations seen crossing granite and similar 
 rock masses. It is further a constituent of metamorphic 
 schists. Sericite, a closely allied variety has been fully 
 described by Ransome in the schists of the Bisbee Quad- 
 rangle, 1 and by the same author in similar rocks of the 
 Globe district. 
 
 Biotite, or the black mica, is similar in composition 
 with the exception that it contains iron and magnesium. 
 It is abundant in Arizona as a rock-forming mineral in 
 the biotite granites, gneisses and metamorphic schists. 
 
 Doubtless other varieties of mica are to be found in 
 Arizona, but as yet they have not been investigated. 
 
 Serpentine 
 
 This is a hydrous magnesium silicate, a secondary 
 mineral resulting from the alteration of such minerals 
 as olivine, pyroxene, hornblende, etc. Such rocks as the 
 peridotites, which are made up almost entirely of these 
 minerals, yield on disintegration large deposits of ser- 
 pentine. It is a rather soft mineral, usually of greenish 
 color and a slight soapy feel. 
 
 i u. s. G. s., PP. NO. 21, p. 25. 
 
OXYGEN SALTS 69 
 
 Ordinary Serpentine. Impure massive serpentine is 
 found associated with magnetite in the Dos Cabesas 
 mountains. A similar mode of occurrence has been noted 
 by Lindgren in the Clifton-Morenci district in the 
 Thompson mine. 1 
 
 Chrysotile or Asbestos. This is the crystallized or 
 fibrous variety of serpentine and is known on the 
 market as asbestos. It is found in the granite gorge of 
 the Grand Canon, 4,000 feet below the rim on the north 
 side of the river, where it is mined by the Hance Asbes- 
 tos Co. The fibers are of excellent quality, of good 
 length and very flexible. The mineral occurs in cracks 
 or seams in the rock where the fibers have arranged them- 
 selves perpendicular to the surfaces. The asbestos seems 
 to be associated with limestone which has become altered 
 through the contact action of intrusive diabase. It is 
 supposed to have resulted from the hydration of the 
 pyroxenes. While the material is, perhaps, of the finest 
 quality of any found in the United States, its inaccessi- 
 bility makes it difficult to work the deposit with profit. 2 
 Another locality has been reported from a place twenty 
 miles west of Globe where it occurs in seams in massive 
 serpentine. 
 
 Talc 
 
 This well-known mineral is also a decomposition pro- 
 duct of ferromagnesium minerals and is frequently met 
 with in the vicinity of mines where metamorphic agencies 
 are at work. It is lighter in color and softer than ser- 
 
 *U. S. G. S., PP. No. 43. 
 2 Mineral Resources, 1908. 
 
7O THE MINERALOGY OF ARIZONA 
 
 pentine. No unusual or particular interesting mode of 
 occurrence has been observed in Arizona. 
 Kaolinite, H 4 A1 2 S1 2 9 
 
 Kaolinite, or as it is more commonly known, kaolin is 
 a secondary mineral resulting from the decomposition of 
 feldspathic minerals. It is consequently always found 
 where weathering and erosion are going on and is hence 
 a constituent of all soils. Only, however, where condi- 
 tions are favorable for a sorting action in quiet water by 
 which the fine clayey material is separated from the sand 
 and gravel, is it found in a comparatively pure state and 
 in quite large deposits. In Arizona, the debris from the 
 mountains is brought down by flood waters and periodi- 
 cally spread upon the plain, a condition very unfavorable 
 to the formation of deposits of kaolin or clay. Yet these 
 deposits, further worked over by less flooded conditions, 
 sometimes give rise to deposits still containing large 
 amounts of sand, but of sufficient purity to be used local- 
 ly for the manufacture of red brick, making it possible 
 for the large towns of the State to have their brickyards 
 where a product of fair quality is manufactured. 
 
 Pure Kaolin. This is frequently met with in the form 
 of soft putty-like masses in many of the mines where it 
 has resulted from a kaolinization of the feldspars. In 
 the Clifton-Morenci district it is reported as accompanying 
 chalcocite in the porphyry ; in small veinlets in quartz at 
 the Hombolt, Ryerson and other mines ; in mammillary 
 masses associated with azurite malachite in the I^ong- 
 
 fellow mine. 1 Associated with limonite, it is found in 
 i u. s. G. s., PP. NO. 43. 
 
OXYGEN SAI/TS 71 
 
 large quantities in the Copper Queen mines, where it has 
 been selected and used as a binding material for the quartz 
 used in lining the converters. 
 
 Graphitic Clay. A large deposit of this variety s of clay 
 is found about seven miles from Benson. It is black and 
 closely resembles soft coal. When ground to a fine pow- 
 der and mixed with water it becomes very plastic. The 
 black color disappears on burning, the mass assuming a 
 buff color. The material has been used for the manufac- 
 ture of pressed brick and is still extensively used in con- 
 verter plants as a binding material, in Cananea, Bisbee 
 and other mining localities. The deposit is said to be 
 almost unlimited in extent. Its composition is illustrated 
 by the following analysis : 
 
 Per cent. 
 
 Silica 59.15 
 
 Iron and alumina 27. 52 
 
 Calcium carbonate 2.82 
 
 Water and undetermined 10.51 
 
 Cement Clay. Doubtless clays or shales of good quali- 
 ty for the manufacture of Portland cement could be found 
 in many places in Arizona were the field throughly pros- 
 pected. At present, however, high freight rates and 
 small local markets combine to make the outlook for the 
 cement industry in Arizona rather discouraging. A 
 government plant has been in operation at Roosevelt 
 where the product was used for the construction of the 
 Tonto dam. The clay found here has the following 
 composition : 
 
72 THE MINERALOGY OF ARIZONA 
 
 Silica 51.91 
 
 Iron and alumina 23.70 
 
 Lime 6. 10 
 
 Magnesia 0.97 
 
 Water 13.40 
 
 Limestone of good quality to combine with the clay is 
 found in the immediate vicinity. 1 
 
 The writer has investigated clay deposits in the vicinity 
 of Flagstaff and found material of very satisfactory com- 
 position for the cement industry. Here it results from 
 the decomposition of black basaltic and andesitic rocks 
 and has collected in a depression caused by a series of 
 lava flows in what is known as Rogers Lake. The deposit 
 is about 700 acres in extent and varies in thickness from 
 three feet near the edges to nine feet near the center. It 
 is yellowish grey, very tough and plastic. Its composition 
 is as follows : 
 
 Per cent. 
 
 Silica 52.94 
 
 Alumina 1 7.91 
 
 Iron oxide .... 9. 23 
 
 Lime 1.22 
 
 Magnesia . 0.42 
 
 Alkalies 2.22 
 
 Water, etc 16.34 
 
 Total 100.28 
 
 A burning test was made on this material using 100 
 parts of clay to 300 parts of limestone. An excellent 
 quality of cement resulted. 
 
 1 U. S. G. S., Bui. No. 243, p. 87. 
 
OXYGEN SALTS 73 
 
 Chrysocolla, CuSi0 3 ,2H 2 
 
 This is a light blue compact mineral, much resembling 
 turquoise, quite common near the surface in many of the 
 mines in the State. In the Globe district it is known 
 to be very abundant, where it occurs in veinlets in im- 
 pure cuprite, in mineralized porphyry, and in associated 
 oxidized minerals. Very beautiful samples are some- 
 times found in which the delicate blue mammillary 
 masses are covered with thin crusts of drusy quartz crys- 
 tals. The mineral as found in the mines is much 
 harder than expected from the descriptions in the text- 
 books. This is because of the silicious matter pres- 
 ent as impurities; in fact, a great deal of the material 
 thought to be chrysocolla is in reality quartz or silica 
 stained with copper minerals. 
 
 Lettsomite 
 
 This is a rare silicate of copper and aluminium. The 
 mineral is sky-blue, fibrous and possesses a silky luster. 
 It has been found in a silicious rock in Arizona in the 
 form of small seams. 1 
 
 (3) PHOSPHATES, VANADATES, ETC. 
 
 Apatite, CaFl, Ca 4 (P0 4 ) 3 
 
 This is found as a universal microscopic accessory in 
 both granitic and eruptive rocks. It appears as minute 
 colorless needles, sometimes tufts, but more often as 
 isolated crystals in the more basic constituents of the 
 
 1 Genth : Am. Jour. Sci. 3d series, 4, p. 119. 
 
74 THE MINERALOGY OF ARIZONA 
 
 rock. As shown by chemical analysis, it is probably a 
 constituent of all soils, its ultimate origin being the 
 microscopic crystals mentioned above. 
 Ecdemite 
 
 This rare chloro-arseniate of lead has been observed as 
 soft drusy incrustations on wulfenite crystals from the 
 Mammoth mine in the Catalina mountains. It is of an 
 orange color, about the same tint as the wulfenite, and can 
 hardly be distinguished from it. Under the microscope, 
 however, the crystallization can easily be distinguished. 
 
 Mimetite 
 
 This also is a rare chloro-arseniate of lead appearing 
 usually as pale yellow incrustations consisting of rounded 
 aggregates. It has been reported from a locality a few 
 miles northwest of the Vulture mine. 1 
 
 Vanadinite, PbCl, Pb 4 (VoJ 3 
 
 This rare and beautiful mineral is frequently met with 
 in Arizona, particularly in quartz veins carrying gold 
 and silver. In composition it is a chloro-vanadate of 
 lead, and ordinarily can be easily recognized by its 
 hexagonal crystallization and its striking red color. It 
 generally appears as incrustations and isolated implanted 
 crystals, sometimes barrel shaped, but more often of good 
 hexagonal development. It is found in the cavities of 
 the vein filling material, a fact which proves that it was 
 deposited during the last stages of mineralization. It is 
 sometimes found even encrusting calcite. Important 
 localities in Arizona are the Red Cloud mine, Yurna Co., 
 
 * Am. Jour. Sci., 3d series, aa, p. 202. 
 
OXYGEN SALTS 75 
 
 the Mammoth mine at Schulz, in the Catalina mountains, 
 Pima Co., and the OldYuma mine, about 14 miles north- 
 west of Tucson. Minerals which are most often asso- 
 ciated with it are, wulfenite, cerussite, ecdemite anddes- 
 cloisite. In the Globe district, where it is also quite 
 common, it occurs along prominent fault fissures in the 
 Apache quartzites. 1 In all of these cases the mineral is 
 found filling cavities and seams in the country rock in 
 the immediate vicinity of the vein as well as in the vein 
 itself. This is especially true of the deposit in the Yuma 
 mine where good vein filling has progressed to only a 
 limited extent. Here the vanadinite and associated min- 
 erals may be found implanted on the surface of planes 
 formed by fractures in the country rock. Fine museum 
 specimens are sometimes found which consist of a slab of 
 the country rock first covered with a layer of calcite, then 
 vanadinite and finally a thin layer of descloisite. Crys- 
 tals have been found over one-fourth inch in diameter. 
 
 The origin of this mineral or the chemical changes 
 which have been concerned in its production are points 
 which have not yet been worked out. Dr. Hillebrand 
 has called attention to the wide distribution of vanadium 
 in the rocks of the United States, 2 and the universal 
 occurrence of apatite with which this mineral is isomor- 
 phous, as microscopic accessories in rocks, is well-known. 
 It may be possible then that the mineral originally ex- 
 isted in minute traces in the apatite molecule in which 
 case the mineral might easily become concentrated by 
 
 1 C. F. Tolman : Private Communication. 
 
 2 U. S. G. S., Bui. No. 305, p. 19. 
 
76 THE MINERALOGY OF ARIZONA 
 
 simple solution, without the intervention of complex 
 chemical reactions. The mineral, however, has been 
 produced artificially by Weinschenk 1 by bringing to- 
 gether, at moderately high temperatures, chloride of lead 
 and vanadium compounds. This investigation would 
 seem to show that if the vanadium originally existed in 
 the complex basic silicate molecule, reactions with lead 
 chloride could take place which would give rise to the 
 mineral. 
 
 Libethenite, Cu 3 P 2 8 , Cu(OH) 2 . 
 
 This is a green basic phosphate of copper. In has re- 
 cently been found in the Coronado mine in the Clifton- 
 Morenci district, as small olive-green crystals less than 
 one millimeter in length. It is associated with quartz 
 and needles of malachite. The mineral was identified by 
 Professor Penfield of Yale and the Caronado mine is 
 probably the only known locality containing it it the 
 United States. 5 
 
 Descloisite and Cupro-descloisite 
 
 These minerals are basic vanadates of lead and zinc 
 usually containing varying quantities of copper and man- 
 ganese. In Arizona they are nearly always found asso- 
 ciated with wulfenite and vanadinite. The most char- 
 acteristic appearance is that of lustrous bronzy or black 
 incrustations rarely more than one or two millimeters in 
 thickness. In some cases the appearance is very much 
 like that of thin varnish on the surface of other minerals. 
 
 1 Brauns : Chemische Mineralogie, p. 270. 
 
 2 U. S. G. S. , PP. No. 43. 
 
OXYGEN SAWS 77 
 
 They are found deposited on calcite, wulfenite and 
 vanadinite crystals, and hence are deposited later. Well- 
 known localities in Arizona are the Castle Dome district, 
 Tombstone, Mammoth mine in the Catalina mountains, 
 and the Old Yum a mine in the Tucson range of moun- 
 tains. The writer has analyzed this mineral from two 
 widely different localities, the results of which are given 
 below. No. i was from the Old Yuma mine in the 
 Tucson mountains, and No. 2 from the Argentine Repub- 
 lic. No. i appeared as crystalline incrustations on crys- 
 tals of vanadinite. These were chosen in preference to 
 the incrustations found on calcite for the reason that it 
 was believed that possible contamination from this source 
 would not be so serious as from the calcite. No. 2 ap- 
 peared as distinct orthorhombic crystals about two milli- 
 meters in length. Analysis No. 2 was conducted in the 
 Fresenius Chemical Laboratories in Wiesbaden, and 
 recognition is due Dr. H. Fresenius and Dr. W. Fresenius 
 for permission to carry on the investigation as well as 
 valuable suggestions regarding the method of analysis. 
 
 No. I No. 2 
 
 Ratios Per cent. Ratios 
 
 Cl 0.08 
 
 Insoluble.. 0.78 
 
 As 2 O 5 o. i r 
 
 PbO 52.26 0.2345 53.36 0.2393 
 
 CuO 11.64 0.1462 i. 21 0.0152 
 
 FeO 0.56 0.0077 
 
 ZnO 6.71 0.0824 13.15 0.1615 
 
 MnO 2.16 0.0304 4.56 0.0642 
 
 V 2 O 5 23.02 0.1262 23.05 0.1263 
 
 H 2 O 2.52 0.1400 2.27 0.1261 
 
 Total 98.31 99-13 
 
78 THE MINERALOGY OF ARIZONA 
 
 Reduced to simpler terms, these ratios become : 
 
 No. i No. 2 
 
 RO 0.4935 = 4 0.4879 = 4 
 
 V 2 O 5 o. 1262 = i o. 1263 = i 
 
 H 2 O 0.1400=1 0.1261^1 
 
 The formula then becomes (RO) 4 . V 2 O 5 . H 2 O, or, 
 R 3 (VO 4 ) 2 . R(HO) 2 , which is that usually given to this 
 mineral. 
 
 The method of analysis briefly outlined is as follows : 
 The finely divided mineral is dissolved in strong nitric 
 acid, diluted and the insoluble residue filtered off, ignited 
 and weighed. In the filtrate, chlorine is determined by 
 means of a standard solution of silver nitrate. The silver 
 chloride is filtered off after adding a few drops of chlor- 
 hydric acid to precipitate excess of silver used in titration. 
 The lead is then precipitated with H 2 SO 4 , removed and 
 weighed. The filtrate is now evaporated to dryness to 
 remove nitric acid. Any further precipitate of lead sul- 
 phate is filtered off and weighed. The solution, properly 
 diluted, is now precipitated with H 2 S, the precipitate dis- 
 solved in nitric acid and reprecipitated. It is then dis- 
 solved again and the copper determined iodometrically. 
 The two filtrates from the H 2 S precipitation are combined, 
 oxidized with nitric acid, and the iron, manganese and 
 zinc separated from vanadium by precipitation with 
 sodium carbonate twice repeated (three precipitations). 
 The three filtrates containing vanadium are combined, 
 evaporated with H 2 SO 4 to remove nitric acid, diluted and 
 reduced with H,S. After removal of H 2 S by boiling and 
 passing in CO 2 , the vanadium is determined by titration 
 
OXYGEN SAI/TS 79 
 
 with a standard solution of permanganate. The precipi- 
 tate of iron, zinc and manganese is now dissolved in HC1 
 and precipitated with NH 4 OH, the precipitate redissolved 
 and a basic carbonate precipitation of iron made with am- 
 monium carbonate. The precipitate is again dissolved and 
 precipitated with NH 4 OH. The iron is then ignited and 
 determined in the usual wa}'. The three filtrates con- 
 taining manganese and zinc are combined, the zinc precip- 
 itated with H 2 S in a very slightly acid solution (with 
 H 2 SOJ , filtered off and ignited in a Rose crucible with 
 hydrogen. The manganese is then precipitated with 
 (NHJ 2 S in an alkaline solution and the MnS ignited in 
 the same manner as the zinc. 
 
 Erythrite, Co 3 As 2 8 .8H 2 
 
 This mineral is sometimes known as cobalt bloom on 
 account of its delicate flower-like tint and frequent radi- 
 ating structure. It is a very rare mineral but has recently 
 been discovered near Jerome where it occurs as soft 
 powder-like incrustations on a dark colored gangue con- 
 taining disseminated grains of cobaltite. It is of a delicate 
 pink color as usual but good crystallizations have not 
 been observed. The deposit is being exploited for the 
 cobalt and already some of the ore has been shipped to 
 New Jersey for treatment. Accurate information regard- 
 ing the mode of occurrence and associations has not yet 
 been obtained. 
 
 Turquoise 
 
 Mineralogically this gem mineral is a phosphate of 
 alumina and copper. Because of its delicate blue color 
 
8O THE MINERALOGY OF ARIZONA 
 
 it has been highly prized by the prehistoric people of 
 western United States and Mexico. It is, therefore, 
 found in many of the Aztec ruins in Mexico and in 
 ruins, of perhaps similar origin, in Arizona. It is found 
 in situ in the Dragoon mountains, on the road between 
 Pearce and Gleason, where it occurs in a greatly decom- 
 posed rock, perhaps a kaolinized rhyolite, in the form of 
 irregular patches and veinlets. When these deposits 
 were first discovered, there were abundant evidences of 
 mining in a crude way, doubtless the work of some 
 Indian tribe or of a prehistoric people. Some implements 
 were found and evidences of the use of fire employed, 
 perhaps, for the purpose of breaking up the rock. An- 
 other important locality is in Mineral Park, Mohave 
 County. During the last two or three years this dis- 
 trict has produced considerable material for the market. 
 Several mining companies are operating in the district, 
 among which may be mentioned the Arizona Turquoise 
 Co., Los Angeles Gem Co., Southwest Turquoise Co., 
 and the Aztec Turquoise Co. The deposit is found in 
 certain hills along the west side of the Cerbat range of 
 mountains, consisting chiefly of gneisses and schists cut 
 by later granites and porphyries. Is is in these latter 
 porphyries that the gem material is found. The porphyry 
 is greatly decomposed in the vicinity of the turquoise. 
 It would appear that some of the turquoise has been 
 formed directly from the kaolinized material by the ad- 
 dition of copper and phosphated material. Gradations 
 are observed between simply copper stained kaolin to 
 
OXYGEN SALTS 8 1 
 
 pure turquoise. An interesting specimen was recently 
 cut by the Los Angeles Co., which consisted of the letter 
 Y in blue in a gray matrix. It was formed by the inter- 
 section of two small veinlets. The stone was sent to a 
 student at Yale. 1 
 
 Nitre, KN0 3 
 
 This well-known compound is frequently formed on 
 old wall, in caves, and on the side of mine shafts, usually 
 however, in such small quantities as to escape obser- 
 vation. It is even said to develop in old morters to the ex- 
 tent of 5 per cent. 2 The writer has observed it associated 
 with sodium carbonate as a thin white covering on the 
 surfaces of the overhanging limestone shelves in the 
 ancient cliff-dwellings of Walnut Canon, about twelve 
 miles from Flagstaff. The walls of the canon here are 
 made up of layers of soft and hard limestone, or more 
 appropriately calcareous sandstone, which has disinte- 
 grated, yielding a series of shelves that have been very 
 conveniently utilized as dwellings by the ancient inhabi- 
 tants of Arizona. 
 
 Nitrocalcite 
 
 This is a hydrous nitrate of calcium sometimes met 
 with in limestone caves, where doubtless an interaction 
 has taken place between the calcium carbonate and bat 
 guano or other organic compounds. A bacteriological 
 action may also be concerned in its formation more or 
 less direct from the atmosphere. It has been reported 
 
 1 Mineral Resources, 1908. 
 
 2 Dana : System of Mineralogy. 
 
82 THE: MINERALOGY OF ARIZONA 
 
 as occurring in the Mammoth Cave in Kentucky. A 
 sample of this mineral mixed with a large quantity of 
 earth was received at the University of Arizona during 
 the summer of 1907 and indentified as calcium nitrate by 
 Dr. A. E. Vinsonof the Agricultural Experiment Station. 
 Correspondence with the sender of the sample brought 
 the following interesting information: "The calcium 
 nitrate occurs in vents in the Lower Carboniferous Lime- 
 stone, fissures that cut across the bedding planes and are 
 therefore perpendicular. There are several of these vents 
 grouped close together exposed to full view in the railroad 
 cut facing the Gila river about two miles above Winkel- 
 man. The face at this spot is a sheer wall about 100 feet 
 high and the vents filled with the nitrate are visible from 
 top to bottom. None of them are more than 6 to 8 inches 
 wide and the nitrocalcite seems to be mixed with red 
 iron." ' 
 
 Gerhardite 
 
 This is a basic copper nitrate found as a coating of dull 
 green color, on the cliffs in the Clifton-Morenci district. 
 It is supposed to have been formed through the action 
 of atmospheric water on copper salts. 2 It is also found in 
 the Jerome district associated with cuprite and malachite. 
 (Dana.) It is a very rare mineral and is never found 
 except as thin coatings or stains on other minerals. 
 
 Colemanite, Ca 2 B 6 O n . 5H 2 
 
 An extraordinary occurrence of this mineral has been 
 
 1 Private communication from Mr. K. B. Zachn, Winkelman, Arizona. 
 
 2 U.S. G. S., PP. No. 43- 
 
OXYGEN SAI/TS 83 
 
 reported by Morgan and Tallmon. 1 It is found asso- 
 ciated with a tar-like substance in a fossil egg found in 
 the placer deposits of the Gila River. 
 
 (4) SULPHATES 
 
 Thenardite, Na 2 S0 4 
 
 This mineral is the sulphate of sodium and usually ap- 
 pears as a dull yellow substance soluble in water. It is 
 found in large deposits in the Verde Valley, Yavapai Co. , 
 near Camp Verde, where, mixed with halite, it is said to 
 have been used as a substitute for salt for cattle and horses. 
 The deposit is several acres in extent and fifty or more feet 
 in depth. It is very compact, mingled with clay, and 
 associated with Mirabilite, halite and glauberite. 2 
 
 Glauberite, Na 2 S0 4 , CaS0 4 
 
 This mineral resembles the one just described but differs 
 from it in containing calcium sulphate in addition to 
 sodium sulphate. As stated above it is found in the Verde 
 Valley associated with other soluble sulphate and chlo- 
 rides. 
 
 Barite, BaSO, 
 
 Barite, or the sulphate of barium, is commonly known 
 as heavy spar because of its high specific gravity. It 
 occurs most often as a gangue mineral, accompanying 
 such sulphides as galena, iron pyrite, etc. It is usually 
 nearly white in color and quite soft. In the Silver Bell 
 
 1 Am. Jour. Sci., 18, 363. 
 
 2 W. P. Blake, Am. Jour. Sci., 3d series, 39, p. 44. 
 
84 THE MINERALOGY 0* ARIZONA 
 
 district, barite is found as lustrous white aggregates of 
 crystals associated with blue cubes of fluospar. In the 
 Quiotoa district it is found in large masses, which on dis- 
 integration, yield aggregates of disk or shell-like shapes. 
 They closely resemble shells which have been cemented 
 together. They are sometimes covered with drusy crys- 
 tals of calcite, siderite, or other similar minerals. It has 
 further been observed in white seams in blue limestone 
 west of the Tucson range of mountains, in the properties 
 south of the San Xavier Mission, associated with argen- 
 tiferous galena, and, in fact, associated with a variety of 
 minerals in many of the mines of the State. 
 
 Anglesite, PbS0 4 
 
 This is the sulphate of lead and represents the first 
 stage in the alteration of galena by which cerussite is 
 finally produced. It being an intermediate product, it 
 is of rarer occurrence that the carbonate, cerussite. 
 When pure it is white and transparent, but more often 
 appears as massive varieties with yellow, gray or nearly 
 black shades. Samples from the Castle Dome district have 
 been described and analyzed by Professor Brush. 1 An in- 
 teresting modification of this mineral came to the writer's 
 notice several years ago. The specimen came from the 
 Tombstone district and exhibited pseudomorphous struc- 
 ture after galena. The sample weighed several pounds 
 and originally consisted evidently of an aggregate of 
 cubic crystals. These have altered to the sulphate in 
 successive stages, giving rise to an appearance that can 
 
 1 Am. Jour. Sci, sd series, 5, p. 421. 
 
OXYGEN SAI/TS 85 
 
 best be described as alligator-skin structure. The succes- 
 sive layers about the original galena granule varied in 
 color from nearly white to dark gray. Small slabs sawed 
 from this specimen present, when polished, a very pleas- 
 ing and striking appearance. 
 
 Crocoitc, PbCrO, 
 
 Chromate of lead is of rather rare occurrence in nature. 
 It appears as bright red crystals and incrustations very 
 much resembling vanadinite, but tetragonal in crystalliza- 
 tion. It is found in the Vulture district associated with 
 wulfenite and vanadinite. As shown by qualitative tests, 
 it seems to be quite frequently mixed, isomorphously 
 perhaps, with wulfenite, and in fact may be the cause of 
 the deep color of many specimens. Samples from the 
 Mammoth mine in the Catalina mountains seem to show 
 a specially large amount of chromium. 
 Vauquelinite 
 
 This very rare phospho-chromate of lead has been re- 
 ported from the Vulture district, where it is associated 
 with crocoite and other lead minerals. 
 Spangolite 
 
 This is a basic sulphate of copper and alumina with 
 some chlorine. It is found in very small quantities in 
 the Metcalf mine of the Clifton-Morenci district in the 
 form of bluish flakes and hexagonal incrustations in 
 sericitized granite-porphyry, associated with cuprite, 
 brochantite and chrysocolla. 1 It has also been reported 
 from the Tombstone district. 
 
 i Undgren : U. S. G* S M PP. No. 43. 
 
86 THE MINERALOGY OF ARIZONA 
 
 Connellite 
 
 This is a rare chlor-sulphate of copper of very complex 
 composition originally occurring at Cornwall. It has 
 recently been discovered in Arizona in the Calumet and 
 Arizona mine in Bisbee. It is described as associated 
 with melanochalcite and chalcophyllite. It was found as 
 dark blue radiating crystals the largest of which was 0.5 
 millimeters in length. The mineral was analyzed with 
 the following results : l 
 
 Per cent. 
 
 S0 8 3.43 
 
 Cl 6.37 
 
 CuO 75.95 
 
 H 2 O 15.07 
 
 Less O Cl 1.42 
 
 Total 100.40 
 
 Brochantite, CuS0 4 , 3Cu(OH) 2 
 
 Many of the green pulverulent minerals of copper, abun- 
 dant in the mines of northern Mexico and Arizona and 
 usually classified by the miners as malachite, have recently 
 been proved to be the basic sulphate of copper or bro- 
 chantite. Mr. Fred Hawley, a student in the University 
 of Arizona together with the writer has investigated the 
 chemical and mineralogical composition of these ores from 
 the Cananea (Mexico) mines and found that they cor- 
 respond quite close to the required formula. Mr. Haw- 
 leys analytical results were as follows : 
 
 * Palache and Merwin: Am. Jour. Sci 28, p. 537. 
 
OXYGEN SAl/CS 87 
 
 CuO 59-00 
 
 SO 8 17-40 
 
 H 2 O 10.70 
 
 A1 2 O 3 720 
 
 FeO and CaO Traces 
 
 SiO 2 5.70 
 
 The alumina and silica are doubtless due to admixtures 
 of kaolin, a mineral with which this compound is fre- 
 quently associated. 
 
 Mr. lyindgren has noted brochantite in quite large 
 quantities, associated with malachite, in the Clifton- 
 Morenci district, and Mr. Ransome in the Copper Queen 
 mines at Bisbee. 1 
 
 Leadhillite, 2PbS0 4 , H 2 CO, 
 
 A rarecarbono-sulphate of lead closely resembling cerus- 
 site occurring at Schulz, Final Co. (Dana's Text-book.) 
 
 Mirabilite, Na 2 S0 4 , ioH 2 
 
 This is a soluble sulphate of soda found in the Verde 
 Valley, associated with thenardite and other soluble min- 
 erals. It seems to overlie the deposit and penetrate it in 
 the form of veinlets. 2 It has also been observed as a 
 white incrustation in the basalt caves near Sunset Peak, 
 about fifteen miles from Flagstaff. (See Ice Caves.) 
 Gypsum, CaS0 4 , 2 H 2 
 
 Gypsum is a very common mineral and, when favorably 
 located, is of commercial value in the manufacture of plas- 
 ters. When burned at proper temperatures it develops 
 the property of combining again with water and forming 
 
 1 U. S. G. S., PP. Nos. 21 and 43. 
 
 2 W. P. Blake : Am. Jour. Sci., 3d series, 39, p. 44. 
 
88 THE MINERALOGY OF ARIZONA 
 
 a hard compact mass. This property is called ' 'setting' 
 and the raw burned material as well as the final product 
 is well known as " plaster of Paris ". Gypsum occurs in 
 nature in three well-known varieties : the fine grained 
 white modification or alabaster, the transparent variety 
 which easily breaks up into thin plates, or selenite, and 
 the fibrous variety or satin spar. Gypsum is slightly 
 soluble in water and since it results in the disintegration 
 of nearly all rocks, through the oxidation of sulphides 
 and interaction with calcium compounds, it is always 
 found, in greater or less quantities, in natural waters. 
 In arid regions like Arizona it is apt to be present in un- 
 usually large proportions. Where circulating water is not 
 sufficiently abundant to carry the material away, it is 
 deposited as a crystallized mineral in the form of impure 
 gypsum. It is consequently very frequently met with in 
 mines where sulphides are oxidizing and reacting with 
 limestone, and where underground water is scarce. 
 Although abundant oxidation has taken place in the Bisbee 
 district, gypsum is entirely absent there because of the 
 transporting action of large volumes of underground 
 water. 1 In the Clifton-Morenci district where under- 
 ground waters are less abundant it is of more common 
 occurrence. 3 These deposits, of course, are not of sufficient 
 size to be of commercial value, but are interesting from 
 the fact that they throw light upon the chemical reac- 
 tions taking place in connection with the deposition of 
 the ore bodies. Deposits of commercial value are formed 
 
 i Ransome : U. S. G. S., PP. No. 21. 
 * I^indgren : U. S. G. S., PP. No. 43. 
 
OXYGEN SALTS 89 
 
 through the evaporation of a lake, pond or arm of the 
 sea. These beds are therefore frequently depositories of 
 common salt, and other soluble minerals. Hence it is 
 found in the Verde Valley associated with thenardite, 
 glauberite and allied minerals. Other places where it has 
 been locally used for the manufacture of plaster, are the 
 low hills along the San Pedro valley, in Fort Apache 
 Reservation, Navajo County, in the Tucson Valley, and 
 near Woodruff and Snowflake in the northern part of the 
 State. 
 
 Epsomite, MgS0 4 , 7H 2 
 
 As the name indicates this mineral is the natural Epsom 
 salt or magnesium sulphate. It has been observed as 
 delicate moss-like efflorescences on the walls of old tun- 
 nels in the mines of the Clifton-Morenci district. 1 
 Goslarite, ZnS0 4 , 7H 2 
 
 This is the soluble sulphate of zinc. It has been ob- 
 served in the Clifton-Morenci district in exactly the same 
 mode of occurrence as epsomite just described. It results 
 from the oxidation of zinc sulphide and being soluble is 
 transported and deposited by the evaporation of percolat- 
 ing water. 
 
 Linarite, (Pb,Cu)S0 4 , (Pb,Cu)(OH), 
 
 This beautiful and rare mineral is found in the Mam- 
 moth-Collins mine at Schulz, Pinal Co., associated with 
 cerussite, wulfenite and other lead minerals. It is deep 
 blue in color and when mingled with pure white ce- 
 russite which is also of adamantine luster, presents an ap- 
 
 1 U. S. G. S., PP. No. 43, p. 121. 
 
9O THE MINERALOGY OF ARIZONA 
 
 pearance of unusual beauty. The crystallization is mono- 
 clinic, but only one crystal perfect enough to measure 
 on the reflecting goniometer has been found. The fol- 
 lowing faces were indentified : a, (100), c, (101), s, 
 (ooi), y, (201), u, (101), w, (212), m, (no), and r, 
 
 (in). 
 
 Chalcantite, CuS0 4 , sH 2 
 
 This is the well-known blue vitriol or blue stone. As a 
 mineral it is frequently met with in copper mines, 
 especially in old workings, where it is frequently found 
 in incrustations on old timbers and the sides of the tun- 
 nels, as well as in the form of stalactites hanging from 
 the roofs of cavities and workings. In some of the old 
 tunnels of the mines in the Clifton- Morenci district it is 
 reported as almost filling the opening with stalactitic 
 masses. 1 In the Jerome district this mode of occurrence 
 is very common ; indeed, the mine waters are especially 
 charged with the mineral, so that it is found worth while 
 to extract the copper by passing the water containing 
 this mineral in solution, over scrap iron. Fine stalactites, 
 received from this locality, were nearly two feet in length. 
 Unfortunately the mineral does not keep well, and the 
 loss of water of crystallization causes it to disintegrate 
 and fall to pieces. 
 
 Copiatite, 2Fe 2 3 , sS0 4 , i8H 2 
 
 This is an unusually rare basic sulphate of iron. A 
 small specimen from the Mineral Hill district has been 
 identified at the University of Arizona. It appears as 
 
 i u. s. G. s., PP. NO. 43. 
 
OXYGEN SALTS $1 
 
 small bright yellow, silky fibers, and slightly foliated 
 masses, not unlike orpiment in general appearance. 
 
 Alunite, K a O, 3A1 2 3 4S0 3 , 6H 2 
 
 This mineral is sometimes known as alum stone. It 
 has been reported as occurring in a narrow seam on a 
 contact between shale and porphyry in the Ryerson mine 
 at Morenci. It is further sometimes found associated 
 with pyrite and kaolin in other parts of the same district. 
 It is described as sometimes quite clayey in appearance 
 so that it might easily be mistaken for that mineral. 1 
 
 Jarosite 
 
 This is usually a ocher-yellow, soft mineral having the 
 composition of the hydrous sulphate of iron and potash. 
 It has been reported from the Vulture mine where it oc- 
 curs associated with gold in quartz. 2 
 Emmonsite 
 
 The composition of this mineral is rather obscure, but 
 it is thought to be a tellurate of iron with water. It has 
 been reported from Tombstone as occurring it thin yellow- 
 ish green scales. 3 
 
 Ettringite 
 
 This is a hydrous sulphate of aluminium and calcium. 
 It is of very rare occurrence. The mineral, however, has 
 been discovered in the Lucky Cuss mine at Tombstone 
 by Mr. W. F. Stanton and described and analyzed by A. 
 J. Moses. It is a white fibrous mineral incrusting a sili- 
 cate of lime and alumina. 4 
 
 1 U. S. G. S., PP. No. 43. 
 
 2 Am. Jour. Sci., sd series, ai, p. 160. 
 8 Dana : Text- Book. 
 
 * Am. Jour. Sci., sd series, 45, p. 489. 
 
92 THE MINERALOGY OF ARIZONA 
 
 (5) TUNGSTATES, MOLYBDATES 
 
 Wolframite, (Fe,Mn)W0 4 , and Huebnerite, MnW0 4 
 These rare and useful minerals have been reported from 
 several localities in Arizona. The two minerals resemble 
 each other so closely and gradate one into the other in such 
 a manner that they can be distinguished only with difficulty 
 without a chemical analysis. The huebnerite, however, 
 usually shows a peculiar internal red reflection by which 
 it can sometimes be distinguished. The two minerals are 
 of equal value in the steel industries. Wolframite was 
 first discovered in Arizona in 1896 by Professor W. P. 
 Blake, then Director of the Arizona School of Mines. It 
 was described as occurring in grains in quartz and asso- 
 ciated with gold in the Arivaca district. 1 Perhaps the 
 most extensively worked deposits are those of the Dragoon 
 mountains near the Southern Pacific railway station of 
 Dragoon Summits. The mineral from this locality was 
 identified at the Arizona School of mines in 1898 as 
 huebnerite and analyses made by the writer. The com- 
 position is represented in the following table : 
 
 FeO 2.66 
 
 W0 3 75.36 
 
 MnO 19.50 
 
 SiO 2 1.70 
 
 Undetermined o. 78 
 
 100.00 
 
 The mineral occurs in extensive quartz veins, perhaps 
 of pegmatitic origin, associated with small quantities of 
 
 i Kng. Min. Jour., 65, p. 607. 
 
OXYGEN SAWS 93 
 
 fluospar and scheelite. The excavation of the vein 
 material is said to be tmremunerative ; gathering the 
 float from the canons and washes seem to be more 
 profitable. Several car-loads of this material were re- 
 ceived at the University of Arizona from the owners, 
 Messrs. Stein and Boericke, for the purpose of concen- 
 tration in the jigs of the School of Mines. The concen- 
 trates contained nearly 70 per cent, of tungstic acid, while 
 the tailings assayed but 0.80 per cent. The price of the 
 material thus concentrated has varied greatly according 
 to the demand ; the value has fluctuated from $80.00 to 
 over $400.00 per ton. 
 
 Another tungsten locality has recently been opened up 
 about 80 miles from Kingman, in the Aquerra range. 
 The mineral is said to occur in grains and in masses 
 /weighing as much as twenty pounds. 1 
 
 Still more recently the mineral has been found in the 
 Whetstone mountains, about 12 miles south of Benson. 
 This deposit is unlike any others of this mineral yet de- 
 scribed. "The deposit is at the base of a steep rise in 
 granite, which is intrusive in a series of metamorphic 
 rocks, including siliceous mica, schist and limestone. The 
 wolframite occurs near the contact of the granite and 
 schist and in a tongue of granite 60 to 70 feet long and 
 perhaps half as wide which runs out into the schist. The 
 granite is very light colored, and except in segregations, 
 contains no dark constituents. A little wolframite is 
 found in the quartz vein, accompanied by small amounts 
 of mica, bornite and probably chalcopyrite. A more 
 
 1 Mineral Resources, 1905. 
 
94 TH E MINERALOGY OF ARIZONA 
 
 noteworthy quantity of wolframite occurs as segrega- 
 tions in the granite. " l In places the material is said 
 to average 10 per cent, tungstic acid, the source being 
 segregations in the granite very much as biotite and 
 hornblende are sometimes collected in irregular patches. 
 The mineral, however, should not be looked upon as an 
 original constituent of granite, but as the result of peg- 
 matitic action. Samples from this locality have been 
 analyzed in the laboratory of the University of Arizona, 
 by Mr. J. M. Ruthrauff. His results are given in the 
 table below. 
 
 Per cent. 
 
 FeO 5.15 
 
 WO S 74. 20 
 
 MnO 18.09 
 
 SiO 2 1.95 
 
 Total 99-39 
 
 Deposits are further found in Sonora, Mexico, so it 
 would seem that the zone in which the mineral occurs is 
 of considerable extent. 
 
 Scheelite, CaW0 4 
 
 This is the calcium tungstate and occurs as a very 
 heavy light yellow or amber colored mineral in the same 
 kinds of formation as wolframite. As mentioned above it 
 is found in small grains associated with wolframite in the 
 Dragoon mountains. It is further found as a microscopic 
 border about the wolframite grains in the whetstone 
 mountains. 2 It is also found in the Old Hat district in 
 
 1 U. S. G. S., Bui. No. 380, p. 164. 
 * U. S. G. S., Bui. No. 380. 
 
OXYGEN SAI/TS 95 
 
 the Catalina mountains, where it is described as occurring 
 in friable masses of light brown. 1 
 
 Wulfenite, PbMoO, 
 
 Chemically this mineral is the molybdate of lead. It 
 is usually found in thin tabular tetragonal crystals vary- 
 ing in color from nearly colorless to deep red or orange. 
 In Arizona the deep orange varieties are, perhaps, the 
 most common. The mineral is found as incrustations, 
 implanted crystals and as massive modifications sometimes 
 filling, together with considerable siliceous matter, rather 
 large veinlets. It is almost always associated with vana- 
 dinite and other minerals of lead and vanadium. It is 
 abundant in the Castle Dome district, the Mammoth 
 mine near Oracle, the Old Yuma mine in the Tucson 
 mountains and many other localities where it is nearly 
 always found in quartz veins associated with gold or 
 silver ores. Interesting samples of this mineral have 
 been received at the University consisting of very intimate 
 association of quartz and wulfenite. The sections for 
 microscopic study have been made of these, and in nearly 
 all cases it has been found that the silica fills up the 
 interstices between the crystals of wulfenite showing that 
 the silicification took place later than the deposition of 
 the molybdate. 
 
 Molybdite 
 
 Molybdite, or as it is sometimes called, molybdic ocher, 
 is a pulverulent yellow mineral, occurring as incrustations 
 and tufts of small fibers in minute cavities and cracks in 
 
 1 W. P. Blake : Rep. to Gov., 1909. 
 
96 THE MINRAI/)GY OF ARIZONA 
 
 the vein material. Its intimate association with molyb- 
 denite or the sulphide, shows without much doubt that 
 it has resulted from the latter through oxidation and 
 other chemical changes. Until recently it has been con- 
 sidered as the trioxide of molybdenum, but the investi- 
 gations of Mr. Schaller 1 has shown it to be a hydrated 
 ferric molybdate. Investigations carried on in the Uni- 
 versity of Arizona further show that the Arizona speci- 
 mens are also a ferric molybdate instead of the oxide. 2 
 In Arizona the mineral is found in white milky quartz, 
 associated with molybdenite and limonite in the Santa 
 Rita mountains. The composition was found on chemi- 
 cal analysis to be as follows : 
 
 Water 17.35 
 
 Fe 2 O 3 21.83 
 
 MoO s 60.80 
 
 These figures resulted after deducting the insoluble 
 residue, which consisted of pure quartz, and recalculating 
 the analysis. The formula deduced from the above fig- 
 ures is Fe 2 (MoO 4 ) 3 7H 2 O. Mr. Schaller's results give 
 7j4 molecules of water of crystallization. 
 
 1 Am. Jour. Sci., 4th series, 23, 297. 
 
 2 Guild : Am. Jour. Sci., 4th series, 23, 455. 
 
VII. NEW MINERALS DISCOVERED IN ARIZONA 
 
 Coronadite 
 
 This is a new mineral recently discovered by Dr. Hil- 
 lebrand. Analysis by Dr. Hillebrand show it to be a man- 
 ganite of lead. It contains 56.13 per cent, of manganese 
 dioxide and 26.48 per cent, of lead oxide. It is described 
 as a dark metallic mineral of fibrous structure and altering 
 to limonite. It is very similar to psilomelane in appear- 
 ance. It was discovered in the Coronado vein in the 
 Clifton-Morenci district, and at present is the only 
 known locality. 1 
 
 Morencite 
 
 This is another new mineral recently discovered in 
 the Morenci mines. It is described as a brownish yellow 
 silky fibrous compound probably resulting from contact 
 conditions in lime shale. The mineral has been analyzed 
 by Dr. Hillebrand with the following results : * 
 
 Per cen 
 
 Si0 2 45.74 
 
 A1 2 3 1.98 
 
 Fe 2 3 29.68 
 
 FeO 0.83 
 
 CaO 1.61 
 
 MgO 3.99 
 
 K 2 O 0.20 
 
 Na 2 O o. 10 
 
 H 2 O, 105 8.84 
 
 H 2 O, 150 0.12 
 
 H 2 O Below redness 4.27 
 
 FeS 2 0.66 
 
 P 2 O 5 0.18 
 
 1 U. S. G. S., PP. No. 43. 
 
 2 U. S. G. S., PP. No. 43, p. 115. 
 
98 THE MINERALOGY OF ARIZONA 
 
 Copper Pitch Ore 
 
 This is an ill defined dark brown to black pitchy appear- 
 ing mineral of copper, found associated with cuprite, 
 chrysocolla, and other minerals of copper in the Copper 
 Queen, Morenci and Globe districts. The mineral has 
 been investigated from time to time but not very conclusive 
 results as to its real nature have been reached. Perhaps 
 the most satisfactory investigations are those of Lindgren 
 and Hillebrand on samples from Clifton. Hillebrand's 
 analysis gave the following results : 
 
 Per cent. 
 
 CuO : 28.6 
 
 ZnO 8.4 
 
 MnO 2 21.2 
 
 Fe, Al and P 4.0 
 
 Insoluble 22.8 
 
 Ignition 13. 7 
 
 From the above preliminary analysis of Dr. Hillebrand 
 the mineral would seem to be some compound of manga- 
 nese and copper. 1 
 
 Quite probably, however, this pitch mineral does not 
 always have the same composition. Professor Koenig 
 had examined some of the same or similar material from 
 Bisbee. As the results of his analysis he considers the 
 mineral to be a basic salt of orthosilico-carbonic acid. 
 He has named the mineral Melanochalcite. 2 
 
 1 U. S. G. S., PP. No. 43, P. H4. 
 
 2 Am. Jour. Sci., 14, p. 404. 
 
NEW MINERALS DISCOVERED IN ARIZONA 99 
 
 Arizonite 
 
 This is a ferric metatitanite and has very recently been 
 discovered on the claims of Mr. A. G. Aim, 25 miles 
 from Hackberry, Arizona. It is associated with Gado- 
 linite. Mr. Palmer found the composition to be as 
 follows: 1 
 
 Per cent. 
 
 FeO 0.70 
 
 Fe,0 3 38.38 
 
 TiO 2 58.26 
 
 H 2 0.18 
 
 H S O, 115 1.02 
 
 1 Palmer : Am. Jour. Sci. 28, p. 353. 
 
INDEX 
 
 PAGE 
 
 Actinolite 58 
 
 Agate 36 
 
 Alabandite 27 
 
 Alunite 91 
 
 Amethyst 41 
 
 Amphibole 5 8 
 
 Andalusite . . 64 
 
 Anglesite 84 
 
 Apatite 73 
 
 Aragonite 48 
 
 Argentite 24 
 
 Arizonite 99 
 
 Arsenic 8 
 
 Asbestos 69 
 
 Atacamite 35 
 
 Augite .... 58 
 
 Aurichalcite 56 
 
 Azurite 55 
 
 Barite 83 
 
 Biotite 68 
 
 Bornite 28 
 
 Bournonite ... 31 
 
 Brochantite 86 
 
 Calamine 66 
 
 Calcite 46 
 
 Caliche 48 
 
 Cement clay 7 1 
 
 Cerargyrite 33 
 
 Cerussite 55 
 
 Chalcantite 90 
 
 Chalcedony 36 
 
 Chalcocite 25 
 
 Chalcophyllite ... 86 
 
 Chalcopyrite 28 
 
 Chalcotrichite 42 
 
 Chrysocolla 73 
 
 Chrysolite 61 
 
 Chrysoprase 40 
 
 PAGE 
 
 Chrysotile 69 
 
 Cinnabar 27 
 
 Clay 70 
 
 Cobalt bloom 79 
 
 Cobaltite 30 
 
 Cohenite 30 
 
 Colemanite 82 
 
 Connellite 86 
 
 Copiapite 90 
 
 Copper ii 
 
 Copper glance 25 
 
 Copper pitch ore 98 
 
 Coronadite 97 
 
 Covellite . . . 28 
 
 Crocoite 85 
 
 Cuprite 42 
 
 Cuprodescloizite 76 
 
 Cyanite 64 
 
 Dannemorite .... 59 
 
 Descloizite 76 
 
 Diamond 5 
 
 Diatomaceous earth 37 
 
 Dolomite 47 
 
 Domeykite 24 
 
 Dioptase ... 62 
 
 Dumortierite 67 
 
 Ecdemite 74 
 
 Embolite 33 
 
 Emmonsite 91 
 
 Epidote 64 
 
 Epsomite 89 
 
 Erythrite 79 
 
 Ettringite 9 1 
 
 Feldspar 5 6 
 
 Flint 4i 
 
 Fluorite 34 
 
 Footeite 35 
 
IO2 
 
 INDEX 
 
 PAGE 
 
 Gadolinite 65 
 
 Galena 25 
 
 Garnet 59 
 
 Gehardite 82 
 
 Glauberite 83 
 
 Gold 9 
 
 Goslarite 89 
 
 Graphite 8 
 
 Graphitic clay 71 
 
 Gypsum 87 
 
 Halite 33 
 
 Heavy spar 83 
 
 Hematite 44 
 
 Hessite 35 
 
 Hornblende 58 
 
 Huebnerite 9 2 
 
 Hyalite 42 
 
 Ice 43 
 
 lodobromite 34 
 
 lodyrite 34 
 
 Iron 14 
 
 Iron pyrites . 29 
 
 Jasper 40 
 
 Jarosite 91 
 
 Kaolin 70 
 
 I^eadhillite 87 
 
 I,ettsomite 73 
 
 I^ibethenite 76 
 
 limestone 46 
 
 I<imonite 45 
 
 Iinarite 89 
 
 Magnetite 45 
 
 Malachite 55 
 
 Marble 48 
 
 Meteoric iron 14 
 
 Mexican onyx 48 
 
 Mica 68 
 
 Microcline 57 
 
 Mimetite 74 
 
 Mirabilite 87 
 
 PAGE 
 
 Molybdenite 23 
 
 Molybdite 95 
 
 Morencite 97 
 
 Muscovite 68 
 
 Nitre 81 
 
 Nitrocalcite 81 
 
 Olivine 61 
 
 Onyx, Mexican 48 
 
 Opal 42 
 
 Orthoclase 56 
 
 Peridot 61 
 
 Petrified wood 38 
 
 Plagioclase 57 
 
 Platinum . . 14 
 
 Polybasite 32 
 
 Proustite 31 
 
 Pyrargyrite 31 
 
 Pyrite 29 
 
 Pyrolusite 45 
 
 Pyrope 60 
 
 Pyroxene 58 
 
 Quartz 36 
 
 Rhodochrosite 55 
 
 Ruby, Arizona 60 
 
 Scheelite 94 
 
 Schreibersite 30 
 
 Semi-opal 42 
 
 Sericite 68 
 
 Serpentine 68 
 
 Siderite 54 
 
 Silver n 
 
 Silver glance 24 
 
 Spangolite 85 
 
 Specular iron 44 
 
 Sphalerite 26 
 
 Stromeyerite 26 
 
 Sulphur 8 
 
INDEX 
 
 103 
 
 Talc 69 
 
 Tenorite 43 
 
 Tetradymite 23 
 
 Tetrahedrite 31 
 
 Thenardite 83 
 
 Topaz 63 
 
 Tourmaline 66 
 
 Tremolite 58 
 
 Turquoise 79 
 
 Vanadinite 74 
 
 Vauquelinite 85 
 
 Vesuvianite 63 
 
 Willemite 62 
 
 Wolframite 92 
 
 Wollastonite 62 
 
 Wulfenite 95 
 
 Zircon 63 
 
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