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Home , Abernathyite, Atacamite, Augelite, Autunite, Coffinite, Lithiophilite

STATE OF SOUTH DAKOTA Nils Boe, Governor

MINERALOGY OF THE BLACK HILLS

by

WILLARD LINCOLN ROBERTS Research Associate in Mineralogy Museum of Geology, South Dakota School of Mines and Technology

and

GEORGE RAPP, JR. Curator of Mineralogy, Museum of Geology, and Associate Professor of Mineralogy, Department of Geology and Geological Engineering, South Dakota School of Mines and Technology

With the Editorial Assistance of RICHARD L. BARTELS, Instructor of Mineralogy South Dakota School of Mines and Technology

BULLETIN NUMBER 18 of the South Dakota School of Mines and Technology Rapid City, South Dakota 1965] DESCRIPTIONS 29

ATACAMITE Cu2(OH)3C1 Class Halide Cryst. Orthorhombic; orthorhombic bipyramidal - 2/m 2/m 2/m Habit Commonly in slender prismatic ; also tabular. In - line aggregates; massive, fibrous, or granular to compact; as sand. Phys. -{ 010 perfect. conchoidal. Brittle. H. 3-31/2. G. 3.8. Luster adamantine to vitreous. Color bright green, dark emerald-green to blackish green. apple-green. Transparent to translucent. Fusible. Easily soluble in acids. Yields water and forms a gray sublimate in closed tube. Occur. Lawrence County: 1. Atacamite occurs as a green staining and as fibers of a bright to dark green color associated with , , matlockite, cerargyrite, , , and in a large mass of , weighing between four and five tons, encountered at the Hill mine, Carbonate. Irving (3) p 178. 2. Small amounts of atacamite have been reported from the Trojan mine at Trojan. Ziegler (5) p 84. Bibliog. Irving, John Duer (3); Ziegler, Victor (5). AUGELITE Al2(PO4)(OH)2 Class Basic Cryst. Monoclinic; monoclinic prismatic - 2/m Habit Tabular crystals and massive. Phys. Good -{ 110 cleavage. Fracture un- even. Brittle. H. 41/2-5. G. 2.696; 2.704 (calc.). Colorless to white. Luster vitreous, pearly on cleavage surfaces. Streak white. Transparent. Infusible. Little affected by acids. Yields much water in a closed tube. Occur. Lawrence County: 1. Augelite has been reported as a minor constituent of the Rough and Ready mine at Tinton x by Hess (10) p 5. Pennington County: 1. Augelite oc- Hugo Mine, Keystone curs at the Hugo mine, Keystone, as light-gray tabular crystals up to 3 by 1 millimeter in size in small vugs and as large cleav- able masses associated with morinite, , montebrasite, and wardite. (SDSM&T-2774) Fisher and Runner (8) p 585. Bibliog. Hess, Frank L. (and Bryan, Barnabus Jr.) (10); Fisher, Daniel Jerome (and Runner, J. J.) (8). AUGITE - See PYROXENE Ca(UO2)2(PO4)2 . nH2O Class Hydrous phosphate Cryst. Tetragonal; ditetragonal bipyramidal - 4/m 2/m 2/m Habit Thin tabular crystals. Also as foliated or scaly aggregates; as thick crusts composed of crystals standing on edge. Phys. Cleavage basal perfect. Not brittle. H. 2-21/2. G. 3.05-3.2, varying with water content. Luster vitreous; pearly on basal plane. Color [Bulletin 18 30 MINERALOGY OF THE BLACK HILLS lemon-yellow to sulfur-yellow, sometimes greenish yellow to pale green. Streak yellowish. Transparent to translucent. Strongly fluor- escent in light; the dehydration product, meta-autunite, is less strongly fluorescent. Fuses easily to a black mass giving a pale-greenish flame. Gives green bead with phosphorous salt. Soluble in acids. It can be distinguished from meta-autunite by its X-ray powder photograph and by its relatively low indices of refraction. Occur. Autunite is a secondary formed by the alteration of uranin- ite or other -containing . It has been found in numerous , in , and in various sedimentary deposits in western South Dakota. Custer County: 1. Autunite occurs sparingly coating fractures in -bearing montebrasite (SDSM&T-3379) at the Mountain mine seven miles west of Custer. 2. Abundant sulfur-yellow autunite occurs as incrusta- tions in joints and cracks of granite (SDSM&T-2244) about 100 feet east of the main pit at the November mine 1.2 miles southeast of the Needles Eye Tunnel on the west side of Highway 87. A similar occurrence along High- way 87 about 300 yards east of the tunnel has been described by A. E. Smith, Jr. (2) p 453. 3. Scaly flakes of autunite have been found coating frac- tures in black and as coatings on feldspar, associated with uraninite and gummite (SDSM&T-3380), at the Ross mine (Highland Lode) about four miles west of Custer. 4. Small amounts of autunite occur as an alteration product of uraninite in nodules of heterosite (SDSM&T-3381) at the Rainbow No. 4 mine about five and one-half miles southwest of Custer. 5. Found sparingly in black tourmaline, associated with small grains of uraninite and gummite, at the High Climb mine just south of the Penning- ton County line about six miles north of Custer. 6. Autunite occurs sparingly with sicklerite, , and uraninite (SDSM&T-3601) at the Custer Moun- tain Lode one and one-half miles east-southeast of Custer. Page (7) p 98. Fall River County: 1. Autunite is found associated with in (SDSM&T-2240) in the mines at Craven Canyon and has been reported as a not uncommon constituent of the uranium- in the Edgemont mining district. Page (8) p 346. Harding County: 1. A yellow-green fluorescent mineral, tenta- tively identified as meta-autunite, occurs with and metator- bernite in unaniferous lignite at the Billy Dale group located on parts of three buttes rising 300 feet above the surrounding plain immediately east of North Cave Hills. Page (8) p 426. 2. Faint green coatings and incrusta- tions of autunite occur in a six inch clinker in the Ludlow formation at the Bobcat mine in the South Cave Hills. Curtiss (2) p 76. 3. Autunite occurs sporadically concentrated in small clusters of aggregates and as disseminated crystals throughout permeable portions of soft carbonaceous material at the Pickpocket No 1 mine in the North Cave Hills. Curtiss (2) p 77. 4. Reported to occur sparsely disseminated in uraniferous lignite, associated with aber- nathyite, , , and in the Slim Buttes area. King (4) p 1. Lawrence County: 1. Autunite occurs in great abundance as apple-green and highly fluorescent well-crystallized plates and crystalline masses as much as 5 millimeters in length coating minute fissures in silt- stone (SDSM&T-937) at the Davier mine on Annie Creek about five miles west of in the Bald Mountain mining district. The autunite is found associated with minutely crystalline purple fluorite, much fluorescent hyalite opal, and stains. Vickers (1) (2). 2. An occurrence of autunite at Bald Mountain has been reported by Stillwell (1) p 82. 1965] DESCRIPTIONS 31

Pennington County: 1. Thick, greenish-yellow incrustations of high- ly fluorescent autunite occur on interlocked aggregates of muscovite, asso- ciated with orange to reddish-brown pseudomorphs and partial pseudomorphs after uraninite crystals, , and , at the Ingersoll mine two miles northwest of Keystone. (SDSM&T-3382). 2. Thin coatings of autunite occur sparingly together with uraninite and gummite in feldspar (SDSM&T- 3383) at the Peerless mine, Keystone. 3. Excellent specimens of highly fluores- cent autunite coating fractures in white , black tourmaline, and pinkish feldspar and associated with uraninite, phosphuranylite, uranophane, and some unidentified alteration products of uraninite (SDSM&T-3384) have been collected from the Ferguson Lode claim about one-half mile northwest of the Wood Tin Lode three miles southeast of Keystone. 4. Reported as a thin bright-yellow coating on flakes and crystals of muscovite and as seamlets in their cleavage planes at the Etta mine, Keystone. Ziegler (5) p 207. 5. Autunite has been reported from the Everly mine (Riverton Lode) located at the junction of Horsely Gulch drainage with Battle Creek at Harney City two miles east of Keystone by Ziegler (5) p 207. Bibliog. Curtiss, Robert Eugene (2); Kepferle, R. C. (1); King, John Wyman (4); Page, Lincoln R. (and others) (7) (8); Smith, Arthur E. Jr. (2); Stillwell, L. W. (1); Vickers, R. C. (1) (2); Ziegler, Victor (5).

AZURITE Cu3(OH)2(CO3)2 Class Basic carbonate Cryst. Monoclinic; monoclinic prismatic - 2/m Habit Crystals usually tabular. Also in crusts, massive and earthy. Phys. Perfect -{ 011 and fair -10(2q cleavage. Fracture conchoidal• Brittle. H. 31/2-4. G. 3.77; 3.83 (calc.). Vitreous to adamantine luster. Color light blue to very dark blue. Streak light blue. Transparent to subtranslucent.

Fuses on charcoal, and with careful treatment will give bead in reducing flame. Dissolves in hydrochloric acid with effervescence. Drop of solution on wire gives fine blue copper flame; ammonia added to green acid solution turns it blue. Occur. is found very sparingly in pegmatites and vein deposits in the Black Hills area. Custer County: 1. Well-developed micro crystals of azurite (SDSM&T-3360) occur in small vugs associated with , montebrasite, , and feldspar at the Tin Mountain mine seven miles west of Cus- ter. 2• Azurite has been observed as thin coatings on rock, associated with malachite, at the Queen mine located near the bottom of the gulch about one-half mile up a short southwesterly bearing branch of French Creek in the NE1/4 of the NE1/4 sec. 14, T4S, R6E. Lawrence County: 1. A small amount of azurite occurs with malachite and tetrahedrite in laminated quartzite on the crest of the divide, between Whitewood and Yellow Creek, just south of Lead. Irving (3) p 95. 2. Minute crystals of azurite associated with malachite (SDSM&T-1952) have been collected from the Jungle mine, Roubaix. It also occurs in other mines of the Custer Peak Copper Co. located about three miles southeast of Cus- ter Peak. Connolly & O'Harra (10) p 210. 3. Azurite has been observed as a secondary mineral with malachite and limonite at the Belle Eldrige mine on the north slope of Spruce Gulch about one and one-half miles by road east-southeast of Deadwood. Davis (1) p 3. Pennington County: 1. Small amounts of azurite associated with malachite occur coating muscovite and fractures in feldspar and 1965] DESCRIPTIONS 49

The crystals occur as single individuals or as regular and complex ag- gregates and show all gradations to rounded bunches, radiating con- cretions, and irregular masses of solid rock, in this deposit of Miocene age. Barbour (2) pp 165-172, well described their occurrence as follows: "The mode of occurrence of these crystals seems most unusual and re- markable. In a bed of sand scarcely 3 feet thick, and so soft as to resemble the sand on the seashore, occur these crystals in numbers which can best be figured in tons. They are mostly single crystals, with numerous doublets, triplets, quadruplets, and multiplets. In other words, every form from solitary crystals to crowded bunches and perfect radiating concretions were obtained. It was a matter of special interest in the to note that at the bottom of the layer the bulk of these sand-lime crystals are solitary; one foot higher there is an evident doubling of the crystals, until within another foot they are in loosely crowded clusters; a little higher in closely crowded continuous clusters, pried out in blocks with difficulty; still higher they occur in closely crowded concretions in contact with one another, making nearly a solid rock. A little higher this mineralizing process culmin- ates in pipes, compound pipes, and solid rocks, composed wholly of cry- stals, but so solidified that their identity is lost, and is detected only by a certain reflection of light, which differentiates the otherwise invisible units by showing glistening hexagonal sections. There could not have been a more gradual and beautiful transition, and all confined to a bed six or eight feet in thickness." Among the forms represented on these crystals, the following have been identified: scalenohedrons modified by a rhombo- hedron; a hexagonal bipyramid modified by a rhombohedron. The following analyses (Ziegler, 1914) illustrate the large amounts of sand enclosed in from this locality: % of sand % of soluble matter Crystals 63.81 36.19 Concretions 61.88 38.12 Sand crystal rock 63.43 36.57 Other localities: 1. has been identified as a major component of the nodules found in the deposits in Brule, Buffalo, Charles Mix, Gregory, Hughes, Lyman, and other counties bordering the Missouri River. Gries & Rothrock (2) p 67. Bibliog. Barbour, E. H. (2) (3); Bassett, William A. (1); Breger, Irving A. (and others) (1); Connolly, Joseph P. (and O'Harra, Cleophas C.) (10); Connolly, Joseph P. (11); Farrington, 0. C. (1) (2); Gries, John Paul (and Rothrock, Edgar Paul) 12); Hovey, E. 0. (1) 12); Johnson, .1. Harlan (1) (2) 13); McConnell, H. N. (1); Neighbor, Frank (1) (2); O'Harra, Cleophas C. (9); O'Harra, Cleophas C. and Connolly, Joseph P. (10); Page, Lincoln R. (and others) (7); Penfield, S. L. (and Ford, W. E.) (1); Schwartz, G. M. 131; Sharwood, W. J. (1); Stabber, George A. (1); Stillwell, L. W. (2); Thomas, Leonard C. (1); Tullis, Edward Langdon (and Gries, John Paul) (1); U. S. Bureau of Mines (6); Wanless, Harold R. (1); Wherry, Edgar T. (1) ; Ziegler, Victor (5). CARBONATE-APATITE - See APATITE SERIES CARNELIAN - See QUARTZ

CARNOTITE KAU02)2(VO 1)2 • n1-1:20 Class Vanadium oxysalt Cryst. Monoclinic; monoclinic prismatic - 2/m Habit As a powder or as loosely coherent microcrystalline aggregates; sometimes in compact masses; also disseminated or as coatings. Phys. Perfect 1 001 cleavage. H. Not known, but soft. G. 4.7. Luster usually dull or earthy; also pearly or showing a silky sheen when 50 MINERALOGY OF THE BLACK HILLS [Bulletin 13 coarsely crystallized. Color bright yellow to lemon-yellow; also greenish yellow. Not fluorescent. Infusible is distinction from ). Easily soluble in acids. Occur. Carnotite is found widespread in Butte, Custer, Fall River, Harding, and Pennington Counties chiefly in , lignite coal, shale, and chal- cedony veins. The first carnotite claims in South Dakota were staked by Jerry G. Brennan, W. L. Roberts, and C. Merle Rowe in the Craven Canyon area about eight miles north of Edgemont on September 4, 1951. Vigorous exploration and mining activities followed and soon over 2,700 mining claims were staked in Fall River and Custer Counties and many more in Butte, Harding, and Pennington Counties. Production has been continuous since 1952, and South Dakota is now recognized as a major uranium producing state. The literature on the mineralogy, geology, and origin of the uranium minerals of South Dakota is vast and is growing constantly. The references given here and the bibliography by Margaret Cooper (1) should serve to guide the reader to other pertinent literature. Although it contains few facts on individual occurrences, the work of Frondel (4) is essential to a serious stu- dent of this subject. Butte County: 1. A significant tonnage of carnotite has been pro- duced from deposits in the Dakota (Fall River) formation six miles west of Belle Fourche in secs. 23, 24, 25, 26, T8N, R1E. The carnotite occurs as a coating and as a disseminated mineral in sandstone (SDSM&T-2323). Custer County: 1. In excess of 7,500 pounds of uranium has been produced from carnotite mined from the Freeze Out mine located on the west side of Bennett Canyon. Potter & Smith (1) p 8. Fall River County: 1. Deposits in the thinly bedded units in the mines in Craven Canyon about eight miles north of Edgemont contain carno- tite, but the halos, concentric irregular bands and fracture fillings contain tyuyamunite. Bell & Bales (1) p 227. Deposits of this type include the Picto- graph mine located on the north side of Craven Canyon. 2. The uranium and vanadium deposits between Coal and Craven Canyons about eight miles north-northwest of Edgemont are predominantly carnotite, tyuyamunite, metatyuyamunite, corvusite, and rauvite. Bell & Bales (1) p 225. The principal mines of this area include the Get Me Rich No. 1, Ridgerunner No. 3, C. No. 2, Road Hog IA and 3A, and Lucky No. 1. Specimens from the Virginia C. mine (SDSM&T-2738) assayed as much as 40% U30s. A musk-ox bone found in one of the mines of the area was partly impregnated with carnotite and afforded a Carbon-14 age determination of 9,700 years. Page (8) p 346. 3. Carnotite is the most important mineral at the Hot Point No. 3 mine located on the east side of Red Canyon. Most of the ore contains only carno- tite finely disseminated in sandstone, but some ore is light brown with splotches and streaks of corvusite, and some is white to pale-gray with a few nodules of corvusite surrounded by carnotite. Bell & Bales (1) p 228. 4. A map show- ing distribution and occurrences of 142 uranium deposits in part of the Edgemont mining district by W. A. Braddock has been published as Mineral Investigations Field Studies Map MF39 by the U. S. Geological Survey, 1955. The locations of uranium mines with production in the Edgemont area are shown on 7.5 minute quadrangle maps prepared by Potter & Smith (1). Harding County: 1. Greenish-yellow, soft powdery carnotite, and possibly tyuyamunite, occurs as thin fillings along the bedding planes, as segregated masses, and as interstitial fillings in the Ludlow sandstone in sec. 9, T18N, R8E. Curtiss (2) p 82. 2. Carnotite-type minerals occur in a channel 1965] DESCRIPTIONS 51 sandstone at the top of the White River group in Cedar Canyon in the NE 1/4 sec. 8, T16N, R8E. Curtiss (2) p 83. 3. Tyuyamunite occurs in the Ludlow sandstone in the Tyboe prospect pit near Reva Gap in the SW 1/4 sec. 10, T18N, R8E. Curtiss (2) p 83. Pennington County: 1. Chalcedony veins, often colored lemon- yellow to greenish-yellow by inclusions of carnotite, occur two miles west of Scenic and in the NE 1/4 NE1/4 sec. 36, T3S, R12E; in the SE 1/4 NE 1/4 sec. 31, T4S, R13E; and in the SW 1/4 NE 1/4 sec. 7, T4S, R13E. Moore & Levish (1) p 4. Specimens suitable for fashioning into attractive cabochon gemstones have been collected from these deposits. 2. Carnotite occurs in the channel sandstones (SDSM&T-2288) in Indian Creek Basin six miles southwest of Scenic. Bibliog. Baker, K. E. (1); Bell, Henry (and Bales, W. E.) (1); Braddock, William Alfred (1) (3); Bright, J. H. (1); Cooper, Margaret (1); Cuppels, N. P. (1); Curtiss, Robert Eugene (2); Frondel, Clifford (4); Gill, James R. (1) (2) (3) (4) (5); Gott, G. B. (1) (2); King, J. W. (1) (2) (3) (4) (5); Moore, George W. (and Levish, Murray) (1); Page, Lincoln R. (and Redden, Jack A.) (6); Page, Lincoln R. (and others) (8); Potter, Lloyd Dean (and Smith, Joseph Blake) (1); Schnabel, Robert Wayne (1) (3); Vickers, R. C. (3) (4). CARPHOSIDERITE (H20)Fe3(SO4)2 (OH)511,20 Class Hydrated basic sulfate Cryst. Hexagonal; ditrigonal pyramidal - 3m. Habit Earthy or minutely scaly crusts and aggregates; reniform. Micro- scopic crystals are hexagonal plates or rhombohedrons. Phys. Cleavage doubtful. H. 4-41/2. G. 2.496-2.905; 3.17 (calc.). Luster dull to resinous or glistening. Color golden yellow, dark straw- yellow. Insoluble in water. Soluble in hydrochloric acid. Occur. Yankton County: 1. Conspicuous bright yellow scales of a mineral tentatively identified as carphosiderite have been found in abundance in well-weathered exposures of the Sharon Springs member of the Pierre shale in the NE 1/4, NE 1/4, sec. 17, T93N, R56W. Simpson, Howard E. (1) p 33. SnO 2 Class Simple oxide Cryst. Tetragonal; ditetragonal bipyramidal - 4/m 2/m 2/m Habit Commonly in well-formed crystals, often bipyramidal, but sometimes prismatic. Also massive in banded fibrous crusts, concretionary masses, and in granular masses. Phys. Poor 100 cleavage. Fracture sub- conchoidal to uneven. Brittle. H. 6-7. G. 6.8-7.1. Luster adamantine to greasy. Color usually black, brownish black, yellowish brown, or reddish brown; occasionally red, yellow, gray, or white; very rarely White Cap Mine, Keystone colorless. Streak brownish, gray, white. Transparent to translucent; some varieties from Black Hills nearly opaque. Infusible. Very slowly attacked by acids. Fragments of cassiterite placed in dilute hydrochloric acid with metallic become coated with a gray or silvery film of metallic tin which turns bright on friction. 1965] DESCRIPTIONS 65

CHRYSOLITE - See OLIVINE HgS There are no authentic occurrences of cinnabar in South Dakota. Finds on Victoria Creek, near Pactola, Rochford, and other localities have been reported intermittently since the commencement of mining in the Black Hills but no reports have been proved. O'Harra (3) p 270; Ziegler (5) p 63. CLAUDETITE As203 This mineral has been reported to occur in some abundance from an unspecified locality near Spokane by Dr. Herman Reinbold. Ziegler (5) p 93. The occurrence has not been authenticated. CLEAVELANDITE - See FELDSPAR GROUP () CLINOCHLORE - See CHLORITE GROUP CLINOPTILOLITE

(NCLCa)2Al2Si7018 . 6H20 Class Tektosilicate Cryst. Triclinic Habit As laths about one micron or less in size in the goundmass of altered pyroclastic sediments. Phys. Standard mineralogical constants such as specific gravity or hard- ness have not been determined with any degree of certainty. Can be clearly distinguished from heulandite by optical, X-ray, thermal and chemical means. Occur. Dewey, Stanley and Lyman Counties: 1. Weathered samples of Pierre shale from the vicinity of Mobridge and Chamberlain, and fresh samples from the Ft. Pierre area contain from 3 to 4 percent clinoptilolite. Tourtelot (1) p 21. Shannon County: 1. Samples of the White River (Oligocene) formation in the Stony Pass section at the southeast end of Sheep Mountain, which were tentatively identified by Wanless (2) p 233 as mordenite, have been re-examined by X-ray techniques and found to contain a mixture of clinoptilolite and erionite. Deffeyes (1) p 508. See erionite for a more com- plete description of the occurrence. Bibliog. Deft eyes, Kenneth S. (1); Tourtelot, Harry A. (1); Wanless, Harold R. (2). CLINOZOISITE - See ZOISITE U(SiO4) 1-x (OH)4x Class Nesosilicate (?) Cryst. Tetragonal; ditetragonal bipyramidal - 4/m 2/m 2/m Habit Found as aggregates or disseminations of extremely small particles. Phys. Pulverulent to friable or brittle. Fracture of aggregates earthy or irregular to subconchoidal. H. 5-6. G. 5.1; ordinarily lower due to porosity and admixture, varying down to about 2.2. Luster dull to adamantine. Color black. Opaque. Decomposed by dilute nitric or sulfuric acids.

66 MINERALOGY OF THE BLACK HILLS [Bulletin 18

Occur. Fall River County: 1. Coffinite has been identified as a con- stituent of uranium-vanadium ore at the Runge mine about six miles north of Edgemont associated with uraninite, haggite, montroseite, , ilsemannite, and jordisite, in a gangue of , calcite, and in sand- stone. (SDSM&T-3426). Myers, A. T. (1) p 39. Bibliog. Gott, Garland B. (and Schnabel, Robert W.) 12); Myers, A. T. (and Hamilton, J. C., and Wil- marth, V. R.) (11; Post, Edwin V. (1). COLUMBITE- SERIES COLUMBITE (Fe,Mn) (Nb,Ta)206 TANTALITE (Fe,Mn)(Ta,Nb)206 Class Multiple oxide Cryst. Orthorhombic; orthorhombic bipyramidal - 2/m 2/m 2/m Habit Crystals short prisms; often rectangular prisms with the pinacoids prominent; sometimes thin to thick tabular; less often pyramidal. In large groups of parallel or subparallel crystals; also massive. Phys. Distinct j 100 and { 010 cleavages. Fracture subconchoidal to uneven. Brittle. H. 6 (columbite), 6-61/2 (tantalite). G. 5.2 (columbite) to 8.0 (tantalite). Color iron-black to brownish black. Frequently tarnished iridescent. Streak dark red to black. Opaque to trans- parent in thin splinters. Infusible and insoluble. Fused with potassium bisulfate, then dissolved in hydrochloric acid, the solution boiled down with tin assumes a deep-blue color. Yields the green color of manganese when fused with . Opt. Orientation n Biaxial Positive X 2.26 Large 2V Y 2.32 Absorption, red-brown, Z ) X 2.43 , 0.17 Tantalite, Black Hills. Headden (1922).

Tantalite Colurnbite (SDSMT - 1209) Helen Beryl Mine, Fourmile Duncan's Little Wonder Mine, Custer Anal. 1 2 3 4 5 6 7 8 MnO 14.79 8.67 7.07 16.25 4.31 5.66 0.81 1.19 FeO 5.45 11.21 11.21 1.89 13.32 11.91 14.00 13.28 SnO2 0.25 0.10 0.32 0.68 WO„ 0.88 0.38 0.44 0.10 Nb205 68.00 61.72 54.09 47.22 34.60 27.22 6.23 1.97 Ta205 9.88 10.93 28.20 34.27 46.02 53.47 78.20 83.57 Rem. 0.53 0.21 1.52 1.30 Total 99.53 100.79 100.88 99.95 100.15 100.00 99.92 100.11 G. 5.201 5.804 5.890 6.170 6.444 6.725 7.773 7.975

1965] DESCRIPTIONS 137 vitreous to sub-adamantine, pearly on basal plane. Color pale green to dark green. Transparent to translucent. Not fluorescent. Easily fusible. Soluble in acids. Occur. Harding County: 1. has been identified, together with metazeunerite and meta-autunite, in uraniferous lignite at the Billy Dale Group located on parts of three buttes rising 300 feet above the surrounding plain immediately east of North Cave Hills. Page (8) p 426. Bibliog. Page, Lincoln R. (and others) (8). METATYUYAMUNITE Ca(UO2)2(VO4)2 • 5H20 Class Vanadium oxysalt Cryst. Orthorhombic; orthorhombic bipyramidal - 2/m 2/m 2/m Habit Crystals are tiny scales and flattened laths. Commonly found as compact to microcrystalline masses; also pulverulent and as thin coatings and films; as an impregnation in sandstone, , and shale. Phys. Perfect micaceous basal cleavage; two other distinct cleavages. Not brittle. H. 2. G. 3.8-3.9. Luster adamantine to waxy. Color canary- yellow to greenish yellow. On exposure to sunlight, the color changes to dark green or yellow-green. Transparent in small grains. Not fluorescent. Fuses easily to a dark liquid. Soluble in nitric, hydrochloric, and sulfuric acids. Occur. Metatyuyamunite is found with tyuyamunite and carnotite as coat- ings or disseminations in sandstones, limestone, and shale at many localities in the uranium mining districts in western South Dakota. Fall River County: 1. Metatyuyamunite is found associated with tyuyamunite and carnotite in sandstone in the Edgemont mining district. Steam (1) p 188. Specific localities are listed under carnotite. Harding County: 1. Metatyuyamunite-bearing carbonaceous shale in commercial-grade deposits, occurs at Slim Buttes, Whetstone Butte, Cave Hills, and Long Pine Hills. Page (8) p 416, 417. Pennington County: 1. Metatyuyamunite has been tentatively identified from a 2 foot thick limestone in the NE1/4 sec. 36, T3S, R12E, four miles southwest of Scenic. The mineral is concentrated in the top inch of the limestone. Moore & Levish (1) p 4. Bibliog. Cuppels, Norman P. (1); Frondel, Clifford (4); Gott, Garland B. (and Schnabel, Robert W.) (2): Moore, George W. (and Levish, Murray) (1); Page, Lincoln R. (and others) (8); Steam, T. W. (and others) (1). META-URANOCIRCITE Ba(UO2)2(PO4)2 • 8H20 Class Hydrous phosphate Cryst. Tetragonal; ditetragonal bipyramidal - 4/m 2/m 2/m (?) Habit Crystals are thin tablets or thin plates with a rectangular outline. Phys. Cleavage basal perfect; distinct prismatic. Not brittle. Thin plates are flexible. H. 2-21/2. G. 4.10 (calc.). Luster pearly on basal planes. Color yellow-green. Transparent. Fluoresces green in ultra-violet light. Fusible. Soluble in acids. Occur. Harding County: 1. Meta-uranocircite occurs sparingly with aber- nathyite disseminated in uraniferous lignite at the Hilltop mine in sec. 12, 138 MINERALOGY OF THE BLACK HILLS [Bulletin 18

T16N, R8E, in the Slim Buttes area. White, E. W. (1) p 18. Lawrence County: 1. Uranocircite (meta-uranocircite) is reported to have occurred at several localities in the refractory siliceous ore mining region in the Bald Mountain area. Irving (3) p 140. Pennington County: 1. Yellowish-green meta-uranocircite occurs associated with apatite and barite in a channel sandstone in the Chadron (formation on the south slope of Hart Table in the NE1/4 sec. 31, T3S, R13E, southwest of Scenic. The sandstone deposit is about one mile long, 500 feet wide, and 7 feet thick; the meta-uranocircite is disseminated in the lower 2 feet, with the greatest mineralization in the basal few inches. Moore and Levish (1) p 4. Bibliog. Gott, Garland B. (and Pipiringos, G. N.) (3); Irving, John Duer (and Emmons, S. F. and Jagger, T. A.) (3) ; Moore, George W. (and Levish, Murray) (1); White, E. W. (1). METAZEUNERITE Cu(UO2)2(As04)2 • 8H20 Class Hydrous Cryst. Tetragonal; ditetragonal bipyramidal - 4/m 2/m 2/m (?) Habit Usually rectangular, flattened tablets; sometimes pyramidal with small terminal faces. Also as subparallel to foliated or micaceous aggregates of platy crystals. Phys. Cleavage basal perfect. Fracture uneven. Brittle. H. 2-21/2. G. 3.79 (calc.). Luster vitreous, pearly on basal plane. Color grass-green to emerald-green. Fluoresces yellow-green in both long and short- wave ultraviolet light. B. B. fusible. Easily soluble in acids. Occur. Harding County: 1. Metazeunerite has been reported to occur sparsely disseminated in uraniferous lignite in the Cave Hills and Slim Buttes areas, associated with autunite, torbernite, , and uranophane. Identified by X-ray pattern, U.S.G.S., King (4) p 1. 2. Metazeunerite, together with metatorbernite and meta-autunite, has been identified in the uraniferous lignite at the Billy Dale Group, located on parts of three buttes rising 300 feet above the surrounding plain, immediately east of the North Cave Hills. Page (8) p 426. Bibliog. Gott, Garland B. (and Pipiringos, G. N.) (3); Kepferle, R. C. (1); King, John Wyman (4); Page, Lincoln R. (and others) (8). METEORITES Seven meteorite falls have been recovered from the Black Hills area. The individual meteorites are as follows: BATH Fell 4:00 P.M. August 29, 1892, near Bath, Brown County, South Dakota. Brecciated spherical chondrite, total weight about 21,260 grams. Merrill (1) p 118, Farrington (2) p 240, Prior (1). Crust dull black, somewhat blebby. Mass ash gray, flecked with rust and containing metallic grains and chondrules. Fine-grained, compact. Museums and organizations known to have or have had portions of this meteorite: Chicago Natural History Museum, U. S. National Museum, Wards Natural Science Establishment, A. E. Foote (Philadelphia), American Museum of Natural History, Harvard Museum, British Museum of Natural History. Bibliog. Farrington, Oliver C. (4); Foote, Albert E. (1) (2); Merrill, George P. (1); Prior, G. T. (1). MINERALOGY OF THE BLACK HILLS [Bulletin 18 alluaudite and loellingite at the Ross mine (Highland Lode) four miles west of Custer. Identified from X-ray pattern by Paul B. Moore, Univ. of Chicago. Pattern on file at SDSM&T. Pennington County: 1. A small dark-yellow to reddish-brown mass of from the Peerless mine at Keystone has been tentatively identified as . Sheridan (3) p 10. Bibliog. Sheridan, Douglas M. (and others) (3). TROEGERITE HMO 2)(As0 4) . 4H20 Troegerite has been reported with uraninite in the Bald Mountain mining district in Lawrence County by E. S. Dana (1) p 860. This occurrence has not been authenticated. TROILITE - See METEORITES and PYRRHOTITE

TUNGSTITE W03 . H2O ? Class Hydrous oxide Cryst. Orthorhombic Habit Massive, pulverulent to earthy, and as microscopic platy crystals. Phys. Cleavage basal perfect. H. 2'/2. G. 5.5 (?). Luster resinous. Color bright yellow, golden yellow, yellowish green. Transparent. Infusible. Soluble in alkalies but not in acids. Occur. Tungstite is an oxidation product of and other minerals. It is found near the surface at many localities where tungsten ore occurs and is often a helpful guide in the location of ore deposits. It some- times colors yellow or greenish and probably occurs in this manner at the Wasp No. 2, Harrison, and other mines in the Lead area. Although tungstite has not been positively identified from any locality in the Black Hills, its probable occurrence in the tungsten mines in the northern Hills and the Hill City vicinity has been suggested by several authors, including Forsyth (1) p 14, 15; Irving (3) p 166; and Runner (2). Bibliog. Forsyth, Alexander (1); Irving, John Duer (and Emmons, S. F., and Jagger, T. A.) (3); Palache, Charles (and Berman, Harry and Frondel, Clifford) (2); Runner, J. J. (and Hartman, M. L.) (2). TURGITE - See LIMONITE TURQUOIS Turquois is reported to have been found as thin bluish-green coat- ings and crusts as an alteration of montebrasite at the Tin Mountain mine seven miles west of Custer. James Allen (p.c. 1960). The occurrence has not been authenticated. TYUYAMUNITE Ca(UO2)2(VO4)2 • 6H20 Class Vanadium oxysalt Cryst. Orthorhombic; orthorhombic pyramidal - mm2 Habit Crystals are minute flattened scales and laths. Often in radial ag- gregates. Commonly massive or compact to microcrystalline; as thin films and coatings; as an impregnation of sandstone. Phys. Perfect j 001 cleavage. Not brittle. H. ," 2. G. 3.3-3.6. Luster adamantine to waxy to dull. Color yellow to canary-yellow or lemon-yellow; on exposure to sunlight, the color changes to green- 19651 DESCRIPTIONS 213

ish yellow or dull green. Translucent to opaque. Not fluorescent. Easily fusible to a dark liquid (a distinction from carnotite). Soluble in dilute acids, except acetic. Occur. Tyuyamunite, the analog of carnotite, occurs as coatings or disseminations in sandstone, limestone, and shale in most of the carnotite deposits in the western part of the state. Occurrences are listed under car- notite since the name carnotite has been loosely used in much of the technologic and mining literature to describe yellow vanadate ores, which usually include tyuyamunite. Bibliog. Curtiss, Robert Eugene (2); Frondel, Clifford (4); Page, Lincoln R. (and others) (8). URALITE - See AMPHIBOLE GROUP URANINITE UO2 Class Simple oxide Cryst. Isometric; hexoctahedral - 4/m 5 2/m Habit Commonly in cubic crystals or cubes modified by octahedral or dodecahedral faces. Also massive, dense to granular; occasionally pulverulent or almost graphitic; as reniform or botryoidal crusts. Phys. Fracture uneven to rough conchoidal. Brittle. H. 5-6. G. 7.5-10 (for natural crystals); 6.5-9 (for pitchblende). Luster submetallic to pitch- like or greasy. Color dark steel-gray to velvety black in crystals; brownish black, dark brown, greenish black, or dark greenish gray in oxidized and altered material. Streak brownish black, grayish, or dull olive-green.

infusible. Readily soluble in nitric and sulfuric acids, more slowly in hydrochloric. A drop of concentrated nitric acid allowed to dry on uraninite dries to leave a fluorescent spot. The powder treated with a drop of nitric acid dries to a brilliantly fluorescent dot. Borax, sodium, and fluoride beads are brilliantly fluorescent in ultraviolet light. Anal. CaO 0.46 MnO 0.001 PbO 16.42 MgO 0.01 (Y,Er2)O3 1.01 La205 0.80 Ingersoll mine, Keystone. CeO2 0.265 Davis analysis (1926). UO2 48.87 Remainder is He 0.08, BaO 0.08, UO3 28.582 alkalies 0.02, MoO3 trace, Th02 2.15 As2O3 0.15, P205 0.06. ZrO2 0.22 SiO2 0.055 Fe2O3 0.30 H2O 0.44 Insol. 0.15 Rem. 0.39

Total 100.123 G. 9.182 Occur. Uraninite is found sparingly in several pegmatites in the Black Hills area and has been mined as an ore mineral from sandstone deposits in the Edgemont district. Custer County: 1. Dendritic aggregates of uraninite crystals as much as 2 inches across occur in feldspar, associated with autunite and gum- mite (SDSM&T-3363) at the Ross Mine (Highland Lode) about four miles west 214 MINERALOGY OF THE BLACK HILLS [Bulletin 18 of Custer. 2. Grains of uraninite up to '/4 inch in diameter, with bright orange to red alteration rims of fourmarierite and vandendreisscheite, occur embedded in heterosite (SDSM&T-3381) at the Rainbow No. 4 mine about five and one- half miles southwest of Custer. 3. Uraninite, in masses up to 1/2 inch across, partially altered to yellow, orange, and red secondary uranium minerals, occurs embedded in montebrasite (SDSM&T-3413) at the Tin Mountain mine seven miles west of Custer. Hess (9) p 536. 4. Minute crystals and small masses of uraninite, in part altered to yellow and orange secondary uranium minerals, occur sparingly embedded in black tourmaline and feldspar (SDSM&T-3494) at the High Climb mine, just south of the Pennington County line, about six miles north of Custer. 5. Minute masses of uraninite occur embedded in sicklerite and lithiophilite, associated with small amounts of autunite and unidentified yellow alteration products, at the Custer Mountain Lode, one and one-half miles east southeast of Custer. (SDSM&T-3615). 6. Uraninite has been identified as a component of the ore at the Triangle mine, about fifteen miles northwest of Edgemont, where it occurs with other uranium-vanadium minerals as an impregnation in sandstone. Schnabel (3) p 210. 7. Uraninite occurs in sandstone together with other uranium-vanadium minerals at the Freezeout mine, about fourteen miles northwest of Edgemont. Schnabel (3) p 210. Fall River County: 1. Uraninite occurs at the Runge mine, about six miles north of Edgemont, associated with coffinite, paramontroseite, hag- gite, jordisite, calcite, pyrite, and . These minerals impregnate the interstices of the sandstone and are found in banded nodules, pods, lenses, or fracture fillings. Two stages of uraninite have been recognized. The first stage is a hard variety that is highly reflective in polished sections; the second stage is a sooty black variety that fills the pore spaces between all the preexisting minerals. Microchemical tests show the presence of iron in both varieties, but the earlier uraninite gives a stronger test. Myers, A. T. (1) p 39; Gott & Schnabel (2) p 177. 2. Uraninite is reported to have been identified in found in the Fall River channel sandstone at the Taylor Lease mine about seven miles north of Edgemont. Potter & Smith (1) p 12. Page (8) p 346. Harding County: 1. Uraninite has been identified by J. W. Gruner from a core of lignite from Flat Top Butte No. B in sec. 27, T22N, R6E, in the Cave Hills area. Kepferle (1) p 246. Lawrence County: 1. An occurrence of uraninite (pitchblende) on Bald Mountain has been doubtfully reported by Stilwell (1) p 82. Pennington County: 1. Superb solid masses of uraninite as much as 5 inches in diameter and 2 inches in thickness, with thick yellow, orange, and red alteration rims of uranophane, kasolite, autunite, fourmarierite, and vandendreisscheite (SDSM&T-938), were mined in 1955 at the Ingersoll mine two miles northwest of Keystone. Also at this locality, isolated orange to reddish-brown pseudomorphs and partial pseudomorphs after well-formed uraninite crystals, as much as 1/2 inch across, occur in coarse aggregates of mica which carries abundant autunite. Davis (1) p 217; Page (5) p 28; Kovarik (1) p 193; Khlopin (1) pp 489-497. 2. Uraninite in partially altered crystals as much as 1/2 inch across, has been found sparingly in feldspar (SDSM&T-3383) at the Peerless mine, Keystone. 3. Velvety black uraninite in crystal masses as much as 3/4 inch in diameter occurs in cleavelandite, associated with white beryl, black tourmaline, autunite, uranophane, phosphuranylite, and other unidentified secondary uranium minerals (SDSM&T-3384), at the Fergu- son Lode claim about one-half mile northwest of the Wood Tin Lode and 1965] DESCRIPTIONS 215

about three miles southeast of Keystone. 4. Uraninite has been reported to occur as an accessory mineral at the Dan Patch pegmatite one mile west of Keystone. Norton (10) p 310. 5. Small amounts of uraninite have been reported to occur in the quartz-cleavelandite-spodumene zone at the Etta mine, Keystone, by Norton (10) p 317. Bibliog. Davis, C. W. (1); Gott, Garland B. (and Pipiringos, G. N.) (3); Gott, Garland B. (and Schnabel, Robert W.) (2); Hess, Frank L. (9) ; Kepferle, R. C. (and Chisholm, W. A.) (1) ; Khlopin, V. G. (1); Kovarik, Alois F. (1); Myers, A. T. (and Hamilton, J. C. and Wllmarth, V. R.) (1); Norton, James Jennings (10); Page, Lincoln R. (5); Page, Lincoln R. (and others) (8); Potter, Lloyd Dean (and Smith, Joseph Blake) (1); Schnabel, Robert W. (3); Stilwell, L. W. (1); Wetherill, George W. (and others) (1); White, E. W. (1). URANOCIRCITE - See META-URANOCIRCITE URANOPHANE Ca(UO2)2(S103)2(OH)2 . 5H20 Class Inosilicate Cryst. Monoclinic Habit Crystals are acicular to hairlike, and occur as stellate or tufted ag- gregates or as crusts. Also massive, microcrystalline, with a fibrous or felted structure and appearing dense to the unaided eye; as soft, shredded, or felted coatings. Phys. Cleavage j 100 perfect. Brittle. H. 21/2. G. 3.7-3.9. Luster vitreous, pearly on cleavage; massive material may appear dull, earthy or waxy. Color lemon yellow to pale straw yellow and honey brown; also greenish yellow to yellowish green; orange yellow. Crystals weakly fluorescent green in ultraviolet light; massive material usual- ly not fluorescent. Soluble in warm hydrochloric acid without effervescence and with a separation of silica gel. Powder dissolved in nitric acid, then poured on streak plate and allowed to dry, is very fluorescent. Occur. In the pegmatites of the Black Hills, uranophane occurs as pseudo- morphs and partial pseudomorphs after uraninite crystals, and if the altera- tion is zonal it constitutes the outermost parts. It also occurs as coatings on cracks in the matrix adjacent to such pseudomorphs. Uranophane also occurs disseminated in uraniferous lignite and in sandstone in western South Dakota. Custer County: 1. Uranophane occurs with fourmarierite and van- dendriesscheite as lemon yellow to orange yellow pseudomorphs after uranin- ite, in masses up to one-half inch across, embedded in montebrasite at the Tin Mountain mine, seven miles west of Custer. (SDSM&T-3413). 2. Tentatively identified as an alteration of uraninite from the Rainbow No. 4 mine, about five and one-half miles southwest of Custer, (SDSM&T-3381); from the High Climb mine, (SDSM&T-3494), just south of the Pennington County line, about six miles north of Custer; and the Ross mine (Highland Lode), (SDSM&T- 3363), about four miles west of Custer. 3. A yellow uranium mineral asso- ciated with malachite and filling interstices in sandstone from the Deadwood formation in a float specimen found approximately 500 feet south- east of the intersection of Lightning Creek and Pleasant Valley Creek has been tentatively identified as uranophane. The specimen contained 1% uranium. Redden (5) p 274. Fall River County: 1. Uranophane has been found in small quanti- ties associated with carnotite and other uranium minerals in the yellow ores in the Edgemont mining district. Typical yellow ore mines are the B and H No. 2, B and H No. 6, Clarabell Nos. 1, 2, 5, Flora, Green Acre No. 3, 4, Gertrude, Hay and Fay, Hot Point Nos. 1, 2, 3, Little Annie, Lucky Toss, Ophelia, Picto- graph, Tess, Helen, Too Late, Western Edge, and Lakota No. 11. Locations of deposits shown on MF 39, by Braddock (1). Gott and Schnabel (2) p 174. 216 MINERALOGY OF THE BLACK HILLS [Bulletin 18 Harding County: 1. Uranophane occurs sparsely disseminated in uraniferous lignite in the Cave Hills and Slim Buttes areas, associated with autunite, zeunerite, abernathyite and torbernite. Identified by X-ray pattern, U. S. Geological Survey. King (4) p 1. 2. Commercial-grade deposits of uranophane bearing sandstone are found at Slim Buttes, Whetstone Butte, Cave Hills and Long Pine Hills. Page (8) p 416, 417. Pennington County: 1. Exceptional specimens of lemon-yellow uranophane, as much as 3/4 inch in thickness and four inches across, occur associated with uraninite, vandendreisscheite, fourmarierite, kasolite and autunite at the Ingersoll mine, two miles northwest of Keystone. It also oc- curs at this locality, associated with other secondary uranium minerals, as pseudomorphs and partial pseudomorphs after uraninite crystals embedded in aggregates of coarse grained mica which carries abundant autunite. Identification confirmed by C. Frondel (p.c.) 1962, and (3) p 558. 2. Beta- uranophane is found as thin lemon yellow crusts on feldspar, associated with white beryl, black tourmaline, uraninite, autunite, phosphuranylite and other unidentified secondary uranium minerals (SDSM&T-3495) at the Ferguson Lode claim three miles southeast of Keystone. 3. Tentatively identified as a con- stituent of "gin/unite" pseudomorphs after uraninite (SDSM&T-3383) from the Peerless mine, Keystone. Bibliog. Braddock, William Alfred (1); Frondel, Clifford (3); Gott, Garland B. (and Schnabel, Robert W.) (2); King, John Wyman (4); Page, Lincoln R. (and others) (8); Redden, Jack A. (5). VANADINITE Pb5(VO4)3C1 Class Chlorovanadate Cryst. Hexagonal; hexagonal bipyramidal 6/m Habit Crystals short to long prismatic, usually with smooth faces and sharp edges; also acicular to hair-like. Sometimes cavernous, the crystals hollow prisms. Phys. Fracture uneven to conchoidal. Brittle. H. 23/4-3. G. 6.88. Luster subresinous to sub-adamantine. Color orange-red, ruby-red, brown- ish red, reddish brown, brown, brownish yellow, yellow, pale straw-yellow. Streak white to yellowish. Subtransparent to nearly opaque. Fused on charcoal with sodium carbonate, the mineral is reduced to metallic lead with a yellow sublimate on the coal. The green bead of vanadium can be obtained with salt. Dissolved in nitric acid and a drop of nitrate added to the solu- tion, silver chloride will be precipitated. Decomposed by hydrochloric acid. Occur. Vanadinite is a secondary mineral found in the oxidized zone of lead deposits in the Black Hills area. Custer County: 1. Vanadinite is reported to have occurred sparing- ly in the upper part of the Spokane lead mine, Spokane, by Ziegler (5) p 198. Lawrence County: 1. A large mass of vanadinite, weighing be- tween four and five tons, associated with galena, cerussite, matlockite, cerargy- rite, wulfenite, pyromorphite, plattnerite, and atacamite was mined from the Iron Hill mine, Carbonate, during silver mining operations in the late 1880's. The vanadinite occurred in small and slender prismatic crystals (SDSM&T- 3326), often hair-like in fineness, of a light-brown color and up to 1/2 inch in length. Irving (3) p 178. 2. Vanadinite has been identified in small amounts among the oxidation products from the Queen mine, Galena. Connolly & O'Harra (10) p 192. Bibliog. Connolly, Joseph P. (and DHarra, Cleophas C.) (10); Irving, John Duer (and Emmons, S. F., and Jagger, T. A.) (3); Ziegler, Victor (5).