igneous
Pumice
Pumice (Vesicular Felsic Igneous Rock)
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, typically white, grey, or yellowish-brown in color, dull to earthy luster, amorphous glassy texture, high porosity resulting in extremely low specific gravity allowing it to float on water.
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Physical properties
Hardness of 6 on Mohs scale, typically white, grey, or yellowish-brown in color, dull to earthy luster, amorphous glassy texture, high porosity resulting in extremely low specific gravity allowing it to float on water.
Formation & geological history
Formed during explosive volcanic eruptions when gas-rich felsic lava cools rapidly, trapping gas bubbles within the rock matrix.
Uses & applications
Used widely in lightweight construction aggregates, abrasive soaps, cosmetic exfoliants, horticulture soil amendments, and stonewashing jeans.
Geological facts
Pumice is the only rock that can float on water due to its high concentration of trapped gas bubbles. It is chemically similar to obsidian.
Field identification & locations
Easily identified in the field by its sponge-like vesicular texture and exceptionally light weight relative to its size. Found globally near active or recent volcanic regions.
