Purity Determination in Gypsum Application Note Gypsum
solution for quality analysis of gypsum (CaSO 4•2H 2O) and the hemihydrate plaster (CaSO 4•½H 2O). Natural Gypsum Gypsum is a mineral found in natural rock. It is extracted either by quarry ing or mining. Pure gypsum contains 79.1% calcium sulfate (CaSO 4) and 20.9% chemically bound water (H 2O). However, since gypsum is a natural material, pure gypsum is rarely found. Natural gypsum ...