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