Hydrothermal Anhydrite in veins is commonly hydrated to gypsum by groundwater in around-area exposures. It is usually linked to the minerals halite and sulfur. Gypsum is the most common sulfate mineral.[seventeen] Pure gypsum is white, but other substances observed as impurities could give a wide array of shades to local https://www.propanraya.com/id/produk/eco-gypsum-ee-4050