igneous
Pumice
Pumice (volcanic glass foam)
AI-generated identification · may be incorrectHardness 6 on Mohs scale, pale grey to white or brown color, dull luster, amorphous glassy crystal structure, very low specific gravity allowing it to float.
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Physical properties
Hardness 6 on Mohs scale, pale grey to white or brown color, dull luster, amorphous glassy crystal structure, very low specific gravity allowing it to float.
Formation & geological history
Formed during explosive volcanic eruptions when gas-rich felsic lava rapidly cools and depressurizes, trapping gas bubbles.
Uses & applications
Used in lightweight concrete aggregates, abrasive stones, exfoliating cosmetics, and horticultural soil amendments.
Geological facts
Pumice is one of the only rocks that can float on water due to its highly vesicular and porous texture.
Field identification & locations
Easily identified by its extremely low weight and floating capability; found globally near active and historical volcanic zones.
