Gypsum TAUNSA  is classified as a sulfate mineral because of the sulfate ions that are present in its structure. With regard to sulfate minerals, gypsum is the most common. The main component of this mineral is hydrated calcium sulfate, or CaSO4•2H2O in chemical terms. Since gypsum is a naturally occurring evaporite mineral, it is frequently found near other minerals like calcite, sulfur, halite, dolomite, and anhydrite. The close relationship between gypsum and anhydrite can be seen by comparing their chemical formulas: CaSO4•2H2O for gypsum and CaSO4 for anhydrite. The important difference is that gypsum has two molecules of water in it, while anhydrite does not. Knowing the differences in hydration between these two minerals is important for comprehending their respective uses and characteristics. The naturally occurring mineral gypsum usually has gentle gray or white hues. It is used in many industries, such as building, gardening, sculpture, and decorative arts, and it mostly forms in layered sedimentary deposits. Gypsum is the most common sulfate mineral and has been used for thousands of years due to its inert and safe properties. Its use in the construction of the Egyptian pyramids is supported by historical evidence.