Pumice

Frothy volcanic glass so full of gas bubbles it can float, used as lightweight aggregate, pozzolan, abrasive and growing medium.

Construction · No. 83

• Not on a critical list

Pumice is lava froth so full of frozen gas bubbles that it floats, and it softened your stone-washed jeans.

Chart: Illustration: Pumice

Where it comes from

Chart: Map of where it comes from

During explosive eruptions, gas-rich lava froths and cools so quickly that the bubbles freeze into glass. World output was about 20 million t in 2025.

Three things to know

1. Turkey produced about 9.7 million t of pumice in 2025, nearly half of the world's 20 million t.
2. Greece supplied 80% of US pumice imports over 2021-24, mainly to east and Gulf coast markets far from western mines.
3. Identified US resources exceed 25 million t, about 58 years at 2025 output.

The journey

1. 1 EruptionGas-rich lava froths and freezes to glass
2. 2 Open pitDug from shallow volcanic deposits
3. 3 SizingCrushed and screened by size
4. 4 DryingDried, then bagged or bulk loaded
5. 5 ProductsLight blocks, concrete, horticulture, denim washing

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