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