Calcium Sulphate

Calcium sulphate is an inorganic white solid with the formula CaSO4. It occurs naturally as a mineral and is also produced synthetically, often as a by-product (e.g. from desulphurisation). The compound exists in three levels of hydration: anhydrous (as mineral anhydrite), dihydrate (gypsum or as mineral selenite) and hemihydrate (Bassanite or plaster of Paris).All forms are poorly soluble in water and cause permanent hardness in water.


Molar Weight172.17 g/mol (dihydrate)
Melting Point1,460°C (anhydrous)
Flash Pointnon flammable
Density2.32 g/cm³ (dihydrate)
FormsPowder, White, Solid

Uses and Applications

Key applications

  • Food additive
  • Oil and Gas
  • Agricultural
  • Pharmaceuticals
  • Animal feed
  • Cosmetic products
  • Building & Construction products


  • Pharma
  • Agrobusiness
  • Animal Nutrition
  • Coatings & Construction
  • Cosmetics
  • Food
  • Oil & Gas

Synonyms: Gypsum, E516, Plaster of Paris, Anhydrite, Selenite, Alabaster

Chemical Formula: CaSO4

CAS Number: 7778-18-9 (anhydrous), 10034-76-1 (hemihydrate), 10101-41-4 (dihydrate)