Pumice: Extraction
How an eruption freezes bubbles into floating rock
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.Pumice forms when gas-rich lava froths during an explosive eruption and cools so fast that the bubbles freeze into glass. Pumicite is the same material as fine volcanic ash. Both are dug from shallow open pits, then crushed and screened by size. No chemical processing is needed. The value lies in the pore structure: low density, insulation and a mild abrasive edge. Finely ground, the glassy silica also reacts with lime, so pumice works as a natural pozzolan in cement. In the US, ten operations in five western states produced in 2025, mostly in remote areas.
Pumice and pumicite (fine volcanic ash) are mined from open pits, crushed and screened into sizes. Coarse grades go to block and aggregate makers; fines and pumicite go to pozzolan, abrasive and filler uses. Mining is simple; the economics are set by freight, since the US average value was only $44/t in 2025. Turkey produces almost half the world's output, followed by Jordan, Greece, Saudi Arabia and Algeria.
Methods compared
| Method | Share of supply | Typical scale | Recovery / efficiency | By-products | Unit cost |
|---|---|---|---|---|---|
| Open-pit mining and crushing of lump pumice | Essentially all US production (USGS 2025) | US average about 43 kt per operation (430 kt from 10 operations, 2025, derived); Turkey 9.7 Mt nationally | n/a | Reject fines | US average unit value $44/t f.o.b. mine or mill (2025, USGS) |
| Pumicite and natural pozzolan production | Included in output of many countries (USGS footnote) | n/a | n/a | n/a | Not available from the sources used |
| Island and coastal quarries for seaborne export (Greece) | Greece produced 1.0 Mt in 2025 and supplied 80% of US imports (USGS) | n/a | n/a | n/a | Not available from the sources used |
How each method works
Open-pit mining and crushing of lump pumiceOverburden is stripped, pumice is dug with loaders, then crushed and screened. Coarse fractions supply lightweight aggregate and stone washing.
Cheap and simple; sensitive to mining and transport costs, and public land rules can limit access (USGS).
USGS MCS 2026 Pumicite and natural pozzolan productionFine volcanic ash and tuff are mined and ground for use as pozzolan in cement and concrete.
Lowers clinker and CO2 in cement; quality varies by deposit.
USGS MCS 2026 Island and coastal quarries for seaborne export (Greece)Greek pumice, notably from the Aegean, is quarried and loaded directly onto ships for European and US markets.
Sea freight extends reach; vulnerable to freight costs.
USGS MCS 2026 Unit economics are indicative ranges from the sources named; costs vary widely by deposit, region and year.Who does it: global
| Company | Country | Activity | Volume | Year | Source |
|---|---|---|---|---|---|
| Hess Pumice Products Private; volumes not published. | US | pumice mining and processing (Idaho) | not published | 2025 | company |
| CR Minerals Private; volumes not published. | US | pumice and pumicite (New Mexico) | not published | 2025 | company |
Who does it: India
India is not listed among pumice producers by USGS (2025). Indian users such as denim laundries and cleaning-product makers rely on imports; no import volume is published separately.