Hydrothermal Anhydrite in veins is usually hydrated to gypsum by groundwater in near-surface area exposures. It is frequently associated with the minerals halite and sulfur. Gypsum is the most typical sulfate mineral.[seventeen] Pure gypsum is white, but other substances found as impurities could give a variety of shades to local https://www.propanraya.com/id/produk/eco-gypsum-ee-4050