Knowra Calcium sulfate Calcium sulfate Calcium sulfate is an inorganic compound with formula CaSO₄. It occurs chiefly as gypsum, which contains water of crystallization, and anhydrite, which does not.
Gypsum : A soft mineral composed of calcium sulfate dihydrate, CaSO₄·2H₂O. This hydrated mineral is calcium sulfate’s most familiar natural form and the source of plaster.
Plaster of Paris : A powder consisting mainly of calcium sulfate hemihydrate, produced by partially dehydrating gypsum. Heating gypsum creates this reactive form of calcium sulfate.
Drywall : A building panel with a gypsum core faced with paper or another covering. Gypsum derived from calcium sulfate forms the core of most drywall.
Calcium carbonate : An inorganic compound with formula CaCO₃, found in limestone, chalk, and many shells. It is a common calcium mineral and industrial material, but contains carbonate rather than sulfate.
Anhydrite : A mineral composed of anhydrous calcium sulfate, CaSO₄. It is the water-free mineral form, contrasting with gypsum’s crystal-bound water.
Calcination : A thermal process that heats a solid to cause decomposition or removal of volatile components. Calcination removes part of gypsum’s crystal water to make plaster of Paris.
Cement : A powdered binder that hardens through chemical reactions with water and binds aggregates in concrete and mortar. Calcium sulfate is added to regulate the setting of Portland cement.
Bassanite : A mineral composed mainly of calcium sulfate hemihydrate, CaSO₄·½H₂O. This rare mineral corresponds to the partially dehydrated composition of plaster of Paris.
Calcium : A chemical element with atomic number 20, classified as an alkaline-earth metal. Calcium supplies the positively charged ion in calcium sulfate.
Hydration reaction : A chemical reaction in which water is incorporated into a substance or its structure. Plaster hardens as calcium sulfate hemihydrate takes up water and forms gypsum.
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