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