Hydrothermal anhydrite in veins is usually hydrated to gypsum by groundwater in near-surface exposures. It is commonly linked to the minerals halite and sulfur. Gypsum is the most common sulfate mineral.[17] Pure gypsum is white, but other substances located as impurities may possibly give a variety of shades to regional https://www.propanraya.com/id/produk/eco-gypsum-ee-4050