Hydrothermal Anhydrite in veins is commonly hydrated to gypsum by groundwater in close to-surface area 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 discovered as impurities might give a wide range of hues to https://www.propanraya.com/id/produk/eco-gypsum-ee-4050