what is hemihydrate
The hemihydrate (CaSO 4 Â·~0.5H 2 O or (CaSO 4) 2 Â·H 2 O) is better known as plaster of Paris, while the dihydrate (CaSO 4 Â·2H 2 O) occurs naturally as gypsum.he anhydrous form occurs naturally as Î²-anhydrite. Depending on the method of calcination of calcium sulfate dihydrate, specific hemihydrates are sometimes distinguished: alpha-hemihydrate and beta-hemihydrate.