In the Frasch method of sulfur mining, a well is drilled into the salt-dome cap-rock, and three pipes, one inside the other, are put into the well. Superheated water under pressure (hotter than 212° Fahrenheit, the temperature at which water ordinarily turns into steam) is sent down one of the pipes to melt the sulfur in the cap-rock around the bottom of the well. Then, compressed air is sent down another of the pipes. This air presses against the liquid sulfur and forces it up to the surface through the third pipe. At the surface, the sulfur is poured into bins, where it cools and becomes a solid again, or it is transported molten, in pipelines and tankers. Sulfur has been obtained from a number of the Texas Gulf Coast salt domes including Bryan Mound, Clemens dome, Damon Mound, and Hoskins Mound in Brazoria County; Palangana dome in Duval County; Long Point dome, Nash dome, and Orchard dome in Fort Bend County; High Island dome in Galveston County; Fannett dome and Spindletop dome in Jefferson County; Moss Bluff dome in Liberty County; Gulf dome in Matagorda County; and Boling dome in Wharton County. In west Texas, sulfur occurs in Permian rocks both at the surface and underground. A small amount of sulfur has been mined in the Rustler Springs area of northeastern Culberson County and northwestern Reeves County, about 50 miles northwest of Pecos. There, scattered grains, crystals, and irregular masses of sulfur occur in cracks and in dissolved-out openings in the Castile Gypsum and in the surface gravel, gypsum, sand, and clay that cover most of this formation. Sulfur has many uses. It is used as an insect-killer, thus helping our food crops to grow. It is used in pulp and paper manufacturing and in the vulcanizing of rubber. Some other uses are in the making of paints, dyes, and explosives. A large amount of sulfur goes to make sulfuric acid, which itself has numerous uses in the chemical, steel, oil refining, and other industries. [Illustration: Sulfur is obtained from the cap-rock of Gulf Coastal Plain salt domes by the Frasch process.] Sulfur Uncemented Sediments Limestone Sulfur-Bearing Limestone Hot Water Melted Sulfur Anhydrite Talc and Soapstone Talc, a hydrous magnesium silicate, is an extremely soft mineral—your fingernail scratches it easily. It has a greasy or a pearly luster, and its color is white, light green, or gray. When rubbed across a streak plate, it leaves a white streak. Talc cleaves perfectly in one direction, and the cleavage fragments are thin, flat, and sheet-like. Its fracture is uneven. This mineral has a soaplike or greasy feel, and it is sectile—a knife will cut through it. Talc is not particularly heavy—it has a specific gravity of 2.7 to 2.8. This mineral seldom occurs with a crystal shape. More commonly it is massive and is granular or layered.