Hydrothermal Anhydrite in veins is often hydrated to gypsum by groundwater in in close proximity to-area exposures. It is frequently affiliated with the minerals halite and sulfur. Gypsum is the most common sulfate mineral.[17] Pure gypsum is white, but other substances discovered as impurities could give a variety of colors https://www.propanraya.com/id/produk/eco-gypsum-ee-4050