Gypsum Powder
Gypsum powder (hydrous calcium sulfate/calcium dehydrate or CaSO42H2O) is a white, smooth powder that is derived from heating gypsum gypsum is heated in air it loses water and converts first to calcium sulfate hemihydrate, (bassanite, often simply called "plaster") and, if heated further, to anhydrous calcium sulfate (anhydrite). Stucco is applied wet and hardens to a very dense .