Hydrothermal anhydrite in veins is often hydrated to gypsum by groundwater in near-surface exposures. It is usually related to the minerals halite and sulfur. Gypsum is the most common sulfate mineral.[seventeen] Pure gypsum is white, but other substances identified as impurities may perhaps give an array of hues to nearby https://www.propanraya.com/id/produk/eco-gypsum-ee-4050