gypsum | Definition, Uses, & Facts | Britannica
Gypsum boards or plasterboards are typical materials used to build light walls. The production process is based on gypsum hydration technology. At the very beginning of the process dehydrated calcium sulfate (gypsum) is converted into CaSO 4 ·0.5H 2 O by heating. Once dehydrated, gypsum is mixed with water, starch, a foaming agent, and other additives.