Hydration Of Anhydrite: Gypsum might also variety with the hydration of anhydrite (CaSO₄). Anhydrite is really a calcium sulfate mineral that lacks the h2o molecules present in gypsum. When exposed to drinking water, anhydrite undergoes a hydration reaction, incorporating water molecules into its construction and transforming into gypsum. Salt Flats: https://www.propanraya.com/id/produk/eco-gypsum-ee-4050