Pyrite is the most wide spread and commonly occurring sulfide mineral. Manufacture of sulfuric acid, and Often mined because it is present in ores containing other more valuable minerals such as gold, silver, copper, cobalt, or nickel. Argentite is found as microscopic grains in rhyolite, an extrusive igneous rock. Native silver, which has a bright, shiny metallic luster, often tarnishes to black on exposure to air. Silver is a heavy, soft, ductile, and malleable metal.
Silver is the best known conductor of heat and electricity.
Calcite and limestone are very abundant earth materials and are among the most widely used in industry. Calcite in the form of limestone is used mainly in the manufacture of portland cement for concrete and mortar in the construction industry. Concrete is used for building, highways, dams, brides, sewers, sidewalks, water pipes, etc. Lime is used in soil stabilizers for construction projects, as a soil neutralizer and conditioner, in calcium phosphate fertilizers, and in pesticides. Finely crushed limestone is the powdery coating on some chewing gum.