igneous
Pumice
Pumice (Vesicular Felsic Igneous Rock)
AI-generated identification · may be incorrectHardness: 6 on Mohs scale. Color ranges from white, grey, yellowish, to brown. Luster is dull to earthy. Structure is highly vesicular and glassy, with zero cleavage and extremely low specific gravity allowing it to float on water.
- Hardness
- 6 on Mohs scale
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Physical properties
Hardness: 6 on Mohs scale. Color ranges from white, grey, yellowish, to brown. Luster is dull to earthy. Structure is highly vesicular and glassy, with zero cleavage and extremely low specific gravity allowing it to float on water.
Formation & geological history
Formed from explosive volcanic eruptions involving high-silica magma that rapidly depressurizes and cools, trapping expanding gas bubbles into glass walls.
Uses & applications
Used widely in lightweight concrete aggregates, abrasive personal care products, stonewashed denim production, and horticultural soil amendments.
Geological facts
Pumice is unique among igneous rocks for its ability to float on water due to its trapped gas bubble network. Large deposits are associated with explosive subduction-zone volcanoes.
Field identification & locations
Identified easily by its extremely light weight, pale color, and abundant visible gas cavities. Common globally near active or historical volcanic arcs, especially the Mediterranean and western US.
