Hydrothermal anhydrite in veins is usually hydrated to gypsum by groundwater in around-area exposures. It is usually associated with the minerals halite and sulfur. Gypsum is the commonest sulfate mineral.[seventeen] Pure gypsum is white, but other substances observed as impurities may give an array of hues to area deposits. Josephine https://www.propanraya.com/id/produk/eco-gypsum-ee-4050