Hydrothermal anhydrite in veins is often hydrated to gypsum by groundwater in near-surface area exposures. It is often associated with the minerals halite and sulfur. Gypsum is the most typical sulfate mineral.[17] Pure gypsum is white, but other substances located as impurities may perhaps give a wide range of hues https://www.propanraya.com/id/produk/eco-gypsum-ee-4050