gypsum

American  

[jip-suhm] / ˈdʒɪp səm /

noun

1. a very common mineral, hydrated calcium sulfate, CaSO 4 ⋅2H 2 O, occurring in crystals and in masses, soft enough to be scratched by the fingernail: used to make plaster of Paris, as an ornamental material, as a fertilizer, etc.

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gypsum British  

/ ˈdʒɪpsəm, dʒɪpˈsɪfərəs, ˈdʒɪpsɪəs /

noun

1. a colourless or white mineral sometimes tinted by impurities, found in beds as an evaporite. It is used in the manufacture of plaster of Paris, cement, paint, school chalk, glass, and fertilizer. Composition: hydrated calcium sulphate. Formula: CaSO 4 .2H 2 O. Crystal structure: monoclinic

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gypsum Scientific  

/ jĭp′səm /

1. A colorless, white, or pinkish mineral. Gypsum occurs as individual blade-shaped crystals or as massive beds in sedimentary rocks, especially those formed through the evaporation of saline-rich water. It is used in manufacturing plasterboard, cement, and fertilizers. Chemical formula: CaSO ₄ ·2H ₂ O.

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Other Word Forms

• gypseous
  adjective
• gypsiferous
  adjective

Etymology

Origin of gypsum

1640–50; < Latin: chalk < Greek gýpsos chalk, gypsum

Explanation

Gypsum is a mineral — specifically, hydrated calcium sulfate — used in making many types of cement and plaster, especially plaster of Paris. It’s also in cement, tofu, and beer. Yum? Gypsum is everywhere! If you're studying chemistry or just want to build something, you may encounter gypsum, which is a white, chalky (or sometimes colorless) mineral used to make plaster of Paris and other building materials such as cement. Plaster of Paris is named from the massive gypsum deposits of Montmartre in Paris. But you won’t just find gypsum in art class. Besides its use in building materials, gypsum is used in making fertilizer and tofu.

Example Sentences

Lynas however, says its by-product from rare earth refining produces a non-toxic, non-radioactive magnesium-rich gypsum and an iron phosphate with a very low level of naturally occurring radioactive material.

From Barron's • Apr. 22, 2026

These included gypsum, carbonates, basalts, dunite, and anorthosite.

From Science Daily • Apr. 8, 2026

For the rest of the building is disappointingly lackluster—boxy white galleries and corridors in “painted gypsum board,” i.e., sheetrock.

From The Wall Street Journal • Dec. 17, 2025

The best remedy for high pH, Wallace said, is to add gypsum to your soil and avoid things that can make the soil more alkaline, such as crushed concrete.

From Los Angeles Times • Apr. 24, 2025

Dad lost his job at the gypsum mine after getting in an argument with the foreman, and when Christmas came that year, we had no money at all.

From "The Glass Castle" by Jeannette Walls

Related Words

• adhesive
• cement
• glue
• lime
• mortar
• stucco