igneous
Pumice
Volcanic glass froth
AI-generated identification · may be incorrectHardness 6 on Mohs scale; light brown to gray color; dull to earthy luster; amorphous glassy structure; very low specific gravity allowing it to float on water.
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Physical properties
Hardness 6 on Mohs scale; light brown to gray color; dull to earthy luster; amorphous glassy structure; very low specific gravity allowing it to float on water.
Formation & geological history
Formed through rapid cooling of gas-rich felsic lava during explosive volcanic eruptions, typically ranging from recent to millions of years old.
Uses & applications
Used widely in lightweight concrete aggregates, abrasive stones, personal care exfoliating products, and horticultural soil amendments.
Geological facts
Pumice is the only rock that can float on water due to its trapped gas bubbles forming a highly vesicular structure.
Field identification & locations
Easily identified by its extremely low weight and frothy texture full of small holes; found globally near active and dormant volcanic regions.
