Gypsum, Size : Upto 50 Mm (90%)

Gypsum has a variety of crystalline forms in which Dihydrate Calcium Sulfate (CaSO4.2H2O) is common and found in Selenite. On a molecular scale it has a lamellar structure in which a layer of water alternates with two layers of CaSO4; hence it can absorb more layers of water. It has an excellent superiority to absorb and release water molecules.From a chemical point of view it is formed by the reactions of Ca and Sulphate Acid present in sea water and deposited in sedimentary layers on the sea bed. Gypsum is produced from open-cast mines that give up to 75% Gypsum. In gypsum calcium or magnesium carbonate, chlorides, other sulphate minerals, clay minerals or silica are considered as deleterious constituents, so normally screened or washed to remove these fine particles. Washing may be added to improve the quality of the material.The gypsum deposits of Bikaner are well known for POP production, cement and fertilizer Industries. It is natural hydrate of calcium sulfate, and partially the plaster of Paris also. The reserves of Gypsum in Bikaner district are estimated as 40.489 million tones.