Names: Calcium sulfate, Plaster of Paris, DrieriteGypsum, Calcium sulfate (anhydrous), Anhydrous calcium sulfate, Anhydrous gypsum, Anhydrous sulfate of lime, Calcium salt of sulfuric acid, CaSO4, Calcium sulphate, Calcium sulfate anhydrous, Sulfuric acid, calcium salt (1:1), [Note: Gypsum is the dihydrate form and Plaster of Paris is the hemihydrate form.]
Appearance: White solid ; White hygroscopic powder or crystalline powder ; Odorless, white powder or colorless, crystalline solid. [Note: May have blue, gray, or reddish tinge.]
Appearance: White powder ; Colourless crystals or white powder ; White, odorless powder. [Note: Readily absorbs CO2 from the air to form calcium carbonate.]