Hydrothermal Anhydrite in veins is often hydrated to gypsum by groundwater in close to-surface exposures. It is frequently related to the minerals halite and sulfur. Gypsum is the commonest sulfate mineral.[seventeen] Pure gypsum is white, but other substances observed as impurities may give a wide range of hues to community https://www.propanraya.com/id/produk/eco-gypsum-ee-4050