Hydrothermal Anhydrite in veins is often hydrated to gypsum by groundwater in close to-surface exposures. It is commonly related to the minerals halite and sulfur. Gypsum is the most typical sulfate mineral.[17] Pure gypsum is white, but other substances uncovered as impurities may give a variety of colors to local https://www.propanraya.com/id/produk/eco-gypsum-ee-4050