Gypsum Selenite, Satin Spar, & Desert Rose

Gypsum is named from Greek "gypsos" - plaster, alluding to its practical use. It has been known from antiquity. Gypsum is composed of hydrated calcium sulphate and takes many forms, occurring as tabular, bladed and diamond shaped crystals. it also occurs in fibrous form, and in compact, granular masses, and as rosette shaped aggregates with included grains of sand.