Gypsum Rock

Gypsum is the common name for the mineral calcium sulfate, which has a chemical formula CaSO4.

Gypsum bonds easily with water and is usually found in its natural state as hydrated calcium sulfate, with a chemical formula of CaSO4.2H20.

Gypsum is a soft mineral that usually appears white or gray and is composed of translucent crystals. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard/sidewalk chalk, and drywall.

Gypsum (CaSO4.2H2O) is very similar to Anhydrite (CaSO4). The chemical difference is that gypsum contains two waters. Gypsum is composed of calcium sulphate (CaSO4) and water (H2O). Its chemical name is calcium sulphate dehydrate (CaSO4.2H2O) and anhydrite is without water. Gypsum is the most common sulfate mineral.