Calcium sulfate. J L RICCI, ... H ALEXANDER, in Bioceramics and their Clinical Applications, 2008. 14.2.1 Gypsum and its derivatives. CS cements begin as gypsum, or calcium sulfate dihydrate (CaSO 4 · 2H 2 O), which is either mined from the earth or produced through more controlled chemical processes (Randolph, 1971).Gypsum and …