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