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Guadalupe Peak and El Capitan in the Guadalupe Mountains,
Culberson County, Texas 1
Earth’s outer crust 2
Geologic time scale 3
Generalized geologic map of Texas 4-5
A mineral is made up of chemical elements 7
A rock is made up of minerals 8
Extrusive igneous rocks form at the earth’s surface 9
Intrusive igneous rocks form beneath the earth’s surface 10
Soils develop from weathered rock and associated organic material
11
Conglomerate from Webb County, Texas 11
Precipitated sediments lining a teakettle 12
Contact metamorphism 13
A scalenohedron 14
Barite specimen showing radial form 15
Chalcedony showing botryoidal form 16
Transparent mineral 16
Streak plate 17
Conchoidal fracture 18
Stalactites and stalagmites in the Caverns of Sonora, Sutton
County, Texas 19
Calcite geode from Travis County, Texas 20
Petrified wood from Texas Gulf Coastal Plain 20
Prospector’s hammer 22
Hand lens 22
Physiographic outline map of Texas 42
Massive anhydrite 43
Amphibole asbestos from Gillespie County, Texas 44
Barite cleavage fragment from west Texas 44
Basalt from Brewster County, Texas 45
Calcite has perfect rhombohedral cleavage 46
Calcite crystals (dog-tooth spar) from the Terlingua area of
Brewster County, Texas 47
Celestite cleavage fragment from Lampasas County, Texas 48
Cinnabar and calcite crystals from the Terlingua area of Brewster
County, Texas 50
Bentonite is used as a drilling-fluid additive 51
Hazel copper-silver mine, Culberson County, Texas 53
Dolomite rock from Burnet County, Texas 54
Feldspar cleavage fragment from Llano County, Texas 55
Microcline feldspar crystals from Llano County, Texas 56
Fluorite has octahedral cleavage 57
Galena has perfect cubic cleavage 57
Garnet crystal forms 58
Gneiss from Blanco County, Texas 59
Placer gold in stream gravels 60
Granite from Gillespie County, Texas 61
Texas State Capitol building at Austin is made of Burnet County
granite 62
Graphite is used in pencil lead, generator brushes, and lubricants
63
Selenite gypsum crystal from Bastrop County, Texas 64
Selenite gypsum rosettes from Nolan County, Texas 64
Fibrous gypsum from Terlingua area, Brewster County, Texas 65
Salt domes occur on the Gulf Coastal Plain 66
Specular hematite from Carrizo Mountains, Hudspeth County, Texas
67
Limestone from Travis County, Texas 68
Limestone quarry at Georgetown, Williamson County, Texas 69
Limonite ore is changed to metallic iron in a blast furnace 71
Metallic iron is made into steel in an open-hearth furnace 72
Magnetite, Llano County, Texas 73
Hollandite from Jeff Davis County, Texas 74
Precambrian metamorphic marble from Llano County, Texas 75
Mica minerals have perfect cleavage in one direction 76
Obsidian arrowheads 77
Opalized wood from Washington County, Texas 78
Quartz-feldspar pegmatite from Burnet County, Texas 79
Pyrite veins in white marble from Llano County, Texas 80
Cubic crystals of pyrite 80
Quartz crystal from Burnet County, Texas 81
Amethyst geode from the Alpine area of Brewster County, Texas 82
Milky quartz from Burnet County, Texas 82
Smoky-quartz crystals from Burnet County, Texas 83
Polished agate from Rio Grande gravels of Zapata County, Texas 83
Jasper from Uvalde County, Texas 84
Sandstone from Zavala County, Texas 86
Prospector 89
Sulfur is obtained by the Frasch process 92
Talc schist from the Allamoore area of Hudspeth County, Texas 93
Topaz crystal from Mason County, Texas 94
Black tourmaline crystals with milky quartz from Llano County,
Texas 95
A Geiger counter is used to detect radioactivity 96