FRONT COVER PHOTO : Gold nugget from Dukes Creek, White County, weight 5 oz., 12 dwt., approx. 2x. BACK COVER PHOTOS: Upper left- Rutile crystal from Graves Mountain, approx. 1.5x. Lower left - Goethite from Pulaski County, approx. lx. Right - Magnetite crystal face showing interference growth, from Lake Lanier area, approx. 1.5x. Photography by S. M. Pickering For convenience in selecting our reports from your bookshelves, they will be color-keyed across the spine by subject as follows: Red Valley & Ridge mapping and structural geology Dk. Purple Piedmont & Blue Ridge mapping and struc- tural geology Maroon Coastal Plain mapping and stratigraphy Lt. Green Paleontology Lt. Blue Coastal Zone studies Dk. Green Geochemical and Geophysical studies Dk. Blue Hydrology Olive Economic geology Mining directory Yellow Environmental studies Engineering studies Dk. Orange Bibliographies and lists of publications Brown Petroleum and natural gas Black Field trip guidebooks. Colors have been selected at random, and will be aug­ mented as new subjects are published. MINERALS OF GEORGIA: THEIR PROPERTIES AND OCCURRENCES by Robert B. Cook STATE OF GEORGIA DEPARTMENT OF NATURAL RESOURCES Joe D. Tanner, Commissioner THE GEOLOGIC AND WATER RESOURCES DIVISION Sam M. Pickering, State Geologist and Division Director ATLANTA 1978 CONTENTS Page Introduction . 1 Classification . 2 Elements ................................................................. 10 Gold ................................................................. 10 Silver ................................................................ 13 Copper .............................................................. 13 Mercury .............................................................. 14 Platinum . 14 Iron, Nickel-Iron ...................................................... 14 Cohenite ......................................................... 17 Schreibersite ...............................................•...... 17 Sulfur ................................................................ 18 Diamond ............................................................. 19 Graphite ............................................................. 20 Sulfides . 22 Tellurobismuthite ..................................................... 22 Tetradymite .......................................................... 22 Chalcocite . 22 Bornite ............................................................... 23 Galena ............................................................... 24 Clausthalite ........................................................... 26 Sphalerite . 26 Chalcopyrite ..................................................... ·. 28 Pyrrhotite . 32 Troilite . 34 Bismuth .............................................................. 34 Valleriite ............................................................. 34 Pentlandite . 34 Cubanite ............................................................. 35 Covellite ............................................................. 35 Stibnite .............................................................. 36 Pyrite ................................................................ 36 Marcasite. 40 Arsenopyrite. 40 Molybdenite .......................................................... 41 Sulfosalts .................................................................. 42 Wittichenite . 42 Tennantite ............................................................ 42 Enargite ... ·............................ : . 42 Zinkenite ............................................................. 43 Oxides and Hydroxides . 44 Cuprite .............................................................. 44 Tenorite .............................................................. 44 Corundum ........................................................... 44 Hematite . 47 llemnite . 49 Pyrophanite . 50 Page Braunite .............................................................. 50 Rutile ................................................................ 51 Pyrolusite ............................................................ 52 Cassiterite . 55 Anatase .............................................................. 55 Brookite .............................................................. 56 Cryptomelane ........................................................ 56 Uraninite ............................................................. 56 Spinel ................................................................ 57 Gahnite .............................................................. 58 Magnetite . 59 Jacobsite . 60 Chromite ............................................................. 60 Columbite-Tantalite ................................................... 61 Euxenite-Polycrase .................................................... 62 Samarskite . 62 Hollandite ............................................................ 63 Lepidocrocite . 63 Boehmite .............................................................. 64 Lithiophorite ......................................................... 64 Romanechite . 64 Manganite ............................................................ 66 Diaspore . 66 Goethite . 67 Gibbsite .............................................................. 71 Halides ................................................................... 73 Fluorite .............................................................. 73 Lawrencite ........................................................... 74 Carbonates . 75 Calcite ............................................................... 75 Magnesite . 76 Siderite . 77 Rhodochrosite . 77 Smithsonite. 78 Aragonite . 78 Cerussite . 79 Dolomite ............................................................. 79 Ankerite . • . 82 Lanthanite ............................................................ 83 Zaratite . 83 Malachite . 83 Azurite ............................................................... 85 Nitrates . 86 Niter ................................................................. 86 Sulfates . 87 Barite ................................................................ 87 Anglesite . 89 Page Mendozite . 89 Kalinite .............................................................. 89 Gypsum .............................................................. 89 Melanterite . 90 Epsomite . 90 Halotrichite ........................................................... 91 Brochantite . 91 Linarite ............................................................... 91 Alunite ............................................................... 92 Jarosite. 92 Langite ............................................................... 92 Phosphates and Arsenates . 94 Xenotime. 94 Monazite . 94 Vivianite . 95 Erythrite. 95 Strengite :. 96 Plumbogummite . 96 Crandallite . 96 Apatite Series . 97 Pyromorophite ........................................................ 98 Lazulite . ..