S Sampling rock or ore 15, 59 Sand 14, 30 Sandstone 30, 41, 43, 53, 55, 66, 73 Sandstone, chemical composition 23 Satinspar gypsum 63 Sedimentary rock 72, 73 Selenite gypsum 63 Shale 19, 20, 24, 50, 53, 55, 66, 73, 74 Shale, chemical composition 23 Shannon County 58 Silica 35, 43, 66 Silver 59, 65 Silver Mines 65 Six-sided crystals 16, 41 Slate 21, 50, 55 Soapstone 21 Soil sweetening 13, 14, 20 Sphalerite 60, 74 “Sponge” limestone rock 13 Stalactites 16 Stalagmites 16 State Geologist, Geological Survey 6, 24, 51, 59 St. Francois County 39, 45 St. Louis County 26 St. Peter sandstone formation 41 Ste. Genevieve 65 Streak of mineral 6, 56 Sulphur 51 Sulphuric acid 10, 53, 63 T Texas County 62 Tiff 16, 61 Travertine 16, 73 Tripoli 37, 43 Tyuyamunite 65, 74 U University of Missouri Geology Department 6 Uranium Minerals 65, 66 V Vanadium 66 Vernon County 32