Calcination: The Powdered gypsum is heated to remove water molecules, manufacturing different kinds of plaster with regards to the temperature and period of heating. Map of gypsum deposits in northern Ohio, black squares show the location of deposits, from "Geography of Ohio", 1923 Gypsum is Utilized in a wide variety https://www.propanraya.com/id/produk/eco-gypsum-ee-4050