A soft white stone, hydrated calcium sulfate mineral, which was a primary or secondary mineral of limestone, shale, marl, and clay. Combined with sand, water, and organic materials, it was used to make plasterlike materials used in cements, coatings, casts, molds, and sculptures. The dense, fine-grained variety is alabaster and was used in architecture. The fibrous massive variety is used for ornaments and jewelry. Nowadays, gypsum is used in the manufacture of plaster of Paris.