Hydrothermal Anhydrite in veins is commonly hydrated to gypsum by groundwater in near-floor exposures. It is usually related to the minerals halite and sulfur. Gypsum is the commonest sulfate mineral.[17] Pure gypsum is white, but other substances observed as impurities may well give an array of colors to nearby deposits. https://www.propanraya.com/id/produk/eco-gypsum-ee-4050