Hydrothermal Anhydrite in veins is usually hydrated to gypsum by groundwater in near-surface exposures. It is usually related to the minerals halite and sulfur. Gypsum is the commonest sulfate mineral.[17] Pure gypsum is white, but other substances uncovered as impurities may perhaps give a wide range of hues to regional https://www.propanraya.com/id/produk/eco-gypsum-ee-4050