Calcium carbonate

Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks as the minerals calcite and aragonite (most notably as limestone, which is a type of sedimentary rock consisting mainly of calcite) and is the main component of pearls and the shells of marine organisms, snails, and eggs. Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create lime scale

Uses:

construction industry, limestone aggregate, cement, oil industry, drilling fluids, ceramic glaze, Paper making, Color industries, Plastic and rubber industries, oil drilling, agriculture, and so on.