Gypsum: Extraction
How evaporating seas made rock you can turn into plaster
What this tab covers How it is mined, drilled or grown, and processed into a tradeable form: the main methods compared, their unit economics, by-products, and the companies that do this work globally and in India.Gypsum is hydrated calcium sulphate that formed as ancient seas and lagoons evaporated, often interbedded with anhydrite, its water-free form. It is quarried or mined underground, crushed and ground. For wallboard and plaster it is calcined, heated to drive off part of its water, making stucco that sets hard again when water is added. Cement makers add raw gypsum to control setting time. A large share now comes as a by-product. Flue-gas desulphurisation at coal power plants makes synthetic gypsum, which supplied about 39% of US supply in 2025.
Gypsum comes from two kinds of source. Natural gypsum is quarried from evaporite beds in more than 78 countries (USGS), led by China, the US, Iran, Oman, Spain and Turkey. Synthetic gypsum is a by-product: FGD gypsum from coal plant scrubbers and phosphogypsum from fertiliser plants. FGD gypsum supplied about 39% of US supply in 2025 but has stopped growing as coal plants close. Most gypsum is either ground raw (cement, farming) or calcined into stucco for board and plaster.
Methods compared
| Method | Share of supply | Typical scale | Recovery / efficiency | By-products | Unit cost |
|---|---|---|---|---|---|
| Open-pit quarrying of natural gypsum | Most of the 160 Mt of world mine output in 2025 (USGS) | US average 0.44 Mt per mine (20 Mt from 45 mines, 2025, derived) | n/a | Anhydrite, selenite | US crude gypsum sold at about $13/t f.o.b. mine in 2025 (USGS) |
| FGD synthetic gypsum from coal power plants | About 39% of US gypsum supply in 2025 (17 Mt, USGS); India produced about 2.1 Mt with a target of 9.9 Mt by 2025-26 (Global Gypsum, 2023) | Output tied to coal burn and sulfur content of coal | n/a | It is itself a by-product of SO2 removal | Low or negative to power plants, which avoid disposal costs (indicative, basis: by-product) |
| Phosphogypsum from phosphoric acid plants | Not published | Several tonnes per tonne of P2O5 produced (indicative, basis: process chemistry) | n/a | Contains fluoride and some radioactivity, limiting use | Near zero at source; treatment adds cost |
| Calcining and wallboard manufacture | US calcined output 18 Mt in 2025 (USGS) | US panel capacity about 34 billion sq ft a year (2025) | n/a | Board scrap recycled onsite | Calcined gypsum about $62/t f.o.b. plant in 2025 (USGS) |
How each method works
Open-pit quarrying of natural gypsumOverburden is removed and gypsum is ripped or blasted, loaded and crushed near the pit. Large quarries in Oman, Spain, Iran and Thailand feed export terminals. In India, RSMML mines gypsum in Bikaner, Barmer and the Thar desert.
Cheap and simple; low value per tonne limits haulage, so ports and coastal plants matter.
USGS MCS 2026; IBM Indian Minerals Yearbook 2022 FGD synthetic gypsum from coal power plantsLimestone slurry scrubs SO2 from flue gas and is oxidised to calcium sulfate, which is dewatered to a fine, pure gypsum. Board plants are often built next to power stations.
High purity and close to markets; declines as coal power is retired.
USGS MCS 2026; Global Gypsum (27 Jul 2023) Phosphogypsum from phosphoric acid plantsSulfuric acid attack on phosphate rock leaves calcium sulfate. Large stacks build up at fertiliser plants; some is used in cement and agriculture after treatment. India's DPIIT began promoting its use in 2023.
Huge stockpiles; impurities and regulation restrict use.
IBM Indian Minerals Yearbook 2022; Global Gypsum (2023) Calcining and wallboard manufactureGround gypsum is heated in kettles or flash calciners to make stucco. Slurry with additives is spread between paper, cut and dried. Plants are capital intensive and regional.
Adds value; energy-intensive drying.
USGS MCS 2026 Unit economics are indicative ranges from the sources named; costs vary widely by deposit, region and year.By-product supply
Synthetic gypsum is a by-product of coal-plant SO2 scrubbing and phosphoric acid production. Its supply depends on coal burn and fertiliser output, not gypsum prices, and it is falling in the US and Europe as coal plants close.
Who does it: global
| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| Knauf (incl. USG since 2019) Private; volumes not published. | Germany | plasterboard, plaster and gypsum mining | not published | 2025 | company |
| Saint-Gobain (Gyproc, CertainTeed, Placo) Gypsum volumes not published. | France | plasterboard and plaster; largest board producer in India | not published | 2025 | Global Gypsum (2023-2024) |
| Etex (Siniat) Volumes not published. | Belgium | plasterboard | not published | 2025 | company |
| Beijing New Building Materials (BNBM) Volume not available from the sources used. | China | plasterboard | not published | 2025 | company |
| Eagle Materials (American Gypsum) Volume not available from the sources used. | US | wallboard | not published | 2025 | company |
Who does it: India
| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| Rajasthan State Mines and Minerals (RSMML) | India | mining of natural gypsum and selenite (Bikaner, Barmer) | 0.18 Mt gypsum sold | FY2026 | Elets eGov (June 2026) |
| Saint-Gobain India (Gyproc) Volume not published. | India | plasterboard (four plants, largest capacity) | not published | 2023 | Global Gypsum (27 Jul 2023) |
| USG Knauf India Volume not published. | India | plasterboard (two plants) | not published | 2023 | Global Gypsum (27 Jul 2023) |
India mined about 4.3 Mt in 2025 (USGS), nearly all in Rajasthan, and has 37 Mt of reserves within 1,330 Mt of resources (IBM, 2015 basis). Cement takes most gypsum: 470 Mt of cement in 2025 at 4-5% implies roughly 19-24 Mt (indicative). The gap is filled by imports, about 90% from Oman (5.3 Mt in 2023), plus FGD gypsum and phosphogypsum. India took 12.0% of world gypsum import value in 2024 (Comtrade).