Hydration Of Anhydrite: Gypsum may variety with the hydration of anhydrite (CaSO₄). Anhydrite can be a calcium sulfate mineral that lacks the water molecules present in gypsum. When subjected to h2o, anhydrite undergoes a hydration response, incorporating water molecules into its composition and reworking into gypsum. Impurities in refinery gypsum https://www.propanraya.com/id/produk/eco-gypsum-ee-4050