Serpentine

Serpentine, hydrous magnesium silicate mineral, Mg₃(Si₂O₅)(OH)₄, that occurs in 2 forms: chrisotile, the fibrous variety which is the primary source of asbestos, and antigorite, the flaky variety. Serpentine, usually green, may also be black, red, yellow, gray, or white. It is used as an indoor building or decorative stone or as a gemstone. Serpentine is widely distributed and is quarried in Quebec, the USSR, South Africa, and the United States.