Hydrothermal Anhydrite in veins is usually hydrated to gypsum by groundwater in around-area exposures. It is frequently affiliated with the minerals halite and sulfur. Gypsum is the commonest sulfate mineral.[seventeen] Pure gypsum is white, but other substances observed as impurities could give a wide array of colours to nearby deposits. https://www.propanraya.com/id/produk/eco-gypsum-ee-4050