Hydrothermal Anhydrite in veins is usually hydrated to gypsum by groundwater in near-surface exposures. It is usually associated with the minerals halite and sulfur. Gypsum is the most typical sulfate mineral.[seventeen] Pure gypsum is white, but other substances observed as impurities may perhaps give a wide range of colours to https://www.propanraya.com/id/produk/eco-gypsum-ee-4050