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