calcium sulphate

a common white or colorless mineral (hydrated calcium sulphate) used to make cements and plasters (especially plaster of Paris)

any of several gypsum cements; a white powder (a form of calcium sulphate) that forms a paste when mixed with water and hardens into a solid; used in making molds and sculptures and casts for broken limbs

a compact fine-textured, usually white gypsum used for carving

gypsum or plaster of Paris spread on a surface to make it suitable for painting or gilding (or a surface so prepared)

finely pulverized gypsum used especially as a pigment