DEPARTMENT OF THE INTERIOR FRANKLIN K. LANE, Secretary UNITED STATES GEOLOGICAL SURVEY GEORGE OTIS SMITH, Director Bulletin 652 4"^ TUNGSTEN MINERALS AND DEPOSITS BY FRANK L. HESS WASHINGTON GOVERNMENT PRINTING OFFICE 1917 ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURED FROM THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, D. C. AT 25 CENTS PER COPY CONTENTS. Page. Introduction.............................................................. , 7 Inquiries concerning tungsten......................................... 7 Survey publications on tungsten........................................ 7 Scope of this report.................................................... 9 Technical terms...................................................... 9 Tungsten................................................................. H Characteristics and properties........................................... n Uses................................................................. 15 Forms in which tungsten is found...................................... 18 Tungsten minerals........................................................ 19 Chemical and physical features......................................... 19 The wolframites...................................................... 21 Composition...................................................... 21 Ferberite......................................................... 22 Physical features.............................................. 22 Minerals of similar appearance.................................. 24 Summary of characteristics.............. 1..................... 24 Distribution................................................... 24 Importance as an ore mineral................................... 25 Hubnerite....................:................................... 25 Physical features.............................................. 25 Minerals of similar appearance.................................. 26 Distribution................................................... 26 Importance as an ore mineral................................... 27 Wolframite........................................................ 27 Physical features.............................................. 27 Minerals of similar appearance........................... ^...... 28 Distribution.................................................. 28 Importance as an ore mineral................................... 2.9 Scheelite.............................................................. 29 Physical features.................................................. 29 Minerals of similar appearance...................................... 30 Summary of characteristics........................................ 31 Distribution...................................................... 31 , Importance as an ore mineral....................................... 32 CuprotungBtite....................................................... 32 Tungstite............!................................................ 33 Ferritungstite......................................................... , 34 Stolzite............................................................... 34 Raspite....................................'........................... 35 Tungsten deposits........................................................ 35 Associated rocks...................................................... 35 Distribution in the United States....................................... 36 3 4 . CONTENT'S. Tungsten deposits Continued. page. Forme................................................................ 37 Segregation deposits.............................................. 37 Pegmatite dikes.................................................. 37 Veins............................................................ 39 Replacement deposits............................................. 40 Contact-metamorphic deposits....................................... 42 Placers................. ; ......................................... 44 Tungsten veins....................................................... 45 Minerals......................................................... 45 Native elements.............................................. 45 Bismuth................... r ............................. 45 Gold..................................................... 45 Graphite................................................. 46 Sulphides, arsenides, antimonides, and tellurides................ 46 Arsenopyrite. ............................................... 46 Bismuthinite.............................................. 46 Chalcocite................................................ 46 Chalcopyrite.............................................. 47. Cinnabar................................................. 47 Cosalite.................................................. 47 Covellite.................................................. 47 Galena.................................................... 47 Molybdenite.......................'........................ 47 Pyrite.. .....^........................................ *. 48 Silver minerals............................................ 48 Sphalerite...........:..................................... 48 Stibnite.................................................... 49 Sylvanite.................................................. 50 Calaverite ............................................... 50 Tetrahedrite.............. v-.............................. 50 Fluorides...................................................... 50 Oxides....................................................... 51 Cassiterite................................................. 51 Chalcedony. ............... ..........................'..... 51 Opal..................................................... 52 Quartz.................................................... 52 Hematite.................................................. 52 Carbonates.................................................... 53 Calcite, dolomite, ankerite, and siderite.................... 53 Silicates....................................................... 54 Feldspars................................................ 54 Beryl..................... *................................ 54 Chlorite.................................................. 54 Muscovite................................................ 54 Lepidolite................................................ 55 Topaz.......... ...................................a ...... 55 Tourmaline..............................:.......-...-..--. 55 Phosphates................................................... 56 Apatite.................................................... 56 Hamlinite (?).............................................. 56 Triplite. .1..................... ......................... 56 Minerals containing columbium and tantalum.................... 57 ILLUSTRATIONS. 5 Tungsten deposits Continued. Tungsten veins Continued. Page. Minerals found in tungsten-bearing pegmatites....................... 58 Outcrops of tungsten veins......................................... 59 Downward extent of tungsten veins................................ 61 Uneven distribution of tungsten in the veins......................... 63 Will tungsten deposits grow richer with depth?...................<s.. 64 Where to prospect for tungsten..................................... 65 Field tests for tungsten minerals............................................ 66 General instructions.................................................... 66 Necessary materials.................................................... 68 Approximate determination of percentage of tungsten in ores.................. 69 Quality of ore demanded by users.......................................... 73 Index................................................................... 81 ILLUSTRATIONS. Page. PLATE I. A, Wedge-shaped ferberite crystals from "Crow patent," Nederland, Colo.; B, Crystallized ferberite with elongated rhombic crystal faces, from Nugget mine, Gilpin County, Colo.-................... 22 II. A, Wedge-shaped ferberite crystals from Hoosier mine, Nederland, Colo.; B, Cuboid ferberite crystals from Georgia A. mine, Neder­ land. Colo...................................................... 23 III. A very fine specimen of ferberite with rhombic crystal faces, from Nugget mine, Gilpin County, Colo.............................. 24 IV. A, Hiibnerite from Birdie mine, Butte, Mont.; B, Hubnerite from Gladstone, near Silverton, Colo.................................. 24 V. A> Wolframite with cinnabar from Jack claim, Clark Mountains, near Nipton, Cal.; B, Black hiibnerite from White Oaks, N. Mex... 24 VI. A, Cutand polished crystal of brown ferberite from Winnebago claim, "near Rollinsville, Colo.; B, Hubnerite crystals from Regan mining district, 35 miles north of Osceola, Nev............................ 26 VII. Wolframite crystals from Jack claim, Clark Mountains, near Nipton, Cal.: A, Wolframite crystal with rounded octahedra of scheelite perched upon it; B, Wolframite crystals, whose faces tend toward a square form, with rounded octahedra of scheelite ................ 27 VIII. Wolframite crystals from Zinnwald,.Bohemia...................... 28 I.. Large, imperfect crystals of wolframite embedded in quartz and chalcopyrite, from Cornwall, England............................ 28 X. A, Scheelite from Papoose mine, Atolia, Cal.; B, Wolframite from Wasp No. 2 mine, 2 miles south of Lead, S. Dak................. 30 XI. A, Scheelite with quartz, pyrite, and galena, from Golden Chest mine,