Gypsum

Category: Geology, Minerals & Industry | GS Paper I and III

SEO Title: Gypsum Mineral: Chemical Formula, Uses, Plaster of Paris and Production in India

UPSC Notes

Gypsum is a soft sulphate mineral used extensively in construction, agriculture and industrial manufacturing.

  • Chemical formula: CaSO₄·2H₂O.

  • Hardness: 2 on the Mohs scale.

  • Formation: Commonly forms as an evaporite mineral.

  • Varieties: Selenite, alabaster and satin spar.

  • Plaster of Paris: Produced by heating gypsum, approximately within the 120–180°C range.

  • Construction: Used in plasterboard and cement to help control setting time.

  • Agriculture: Supplies calcium and sulphur and helps improve sodic soils.

  • Industrial by-product: Phosphogypsum is generated during phosphoric acid and fertiliser production.

  • Indian production: Rajasthan is the leading producer, with important deposits in Bikaner, Jaisalmer and Nagaur.

Key Pointers for Prelims

  • Gypsum contains chemically bound water.

  • Plaster of Paris is calcium sulphate hemihydrate.

  • Rajasthan is India's leading gypsum-producing state.

  • Gypsum has both industrial and agricultural applications.