Hydrothermal anhydrite in veins is usually hydrated to gypsum by groundwater in in close proximity to-floor exposures. It is often affiliated with the minerals halite and sulfur. Gypsum is the commonest sulfate mineral.[17] Pure gypsum is white, but other substances identified as impurities could give a wide range of colors https://www.propanraya.com/id/produk/eco-gypsum-ee-4050