Hydration Of Anhydrite: Gypsum may also variety with the hydration of anhydrite (CaSO₄). Anhydrite is often a calcium sulfate mineral that lacks the drinking water molecules present in gypsum. When exposed to h2o, anhydrite undergoes a hydration response, incorporating drinking water molecules into its structure and reworking into gypsum. Rehydration: https://www.propanraya.com/id/produk/eco-gypsum-ee-4050