- calcined gypsum in white, powdery form, used as a base for gypsum plasters, as an additive of lime plasters, and as a material for making fine and ornamental casts: characterized by its ability to set rapidly when mixed with water.
- a white powder that sets to a hard solid when mixed with water, used for making sculptures and casts, as an additive for lime plasters, and for making casts for setting broken limbs. It is usually the hemihydrate of calcium sulphate, 2CaSO 4 .H 2 O
- the hard plaster produced when this powder is mixed with water: a fully hydrated form of calcium sulphate
