igneous
Pumice
Pumicite / Felsic Vesicular Volcanic Glass
AI-generated identification · may be incorrectHardness around 5.5–6 (Mohs), light gray to whitish, dull earthy luster, highly vesicular and lightweight with low bulk density (often floats on water).
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Physical properties
Hardness around 5.5–6 (Mohs), light gray to whitish, dull earthy luster, highly vesicular and lightweight with low bulk density (often floats on water).
Formation & geological history
Formed during explosive volcanic eruptions when highly pressurized, gas-rich felsic magma rapidly expands and cools into frothy glass.
Uses & applications
Commonly used as an industrial abrasive, lightweight concrete aggregate, soil conditioner in horticulture, and cosmetic exfoliating stone.
Geological facts
Pumice is essentially solidified volcanic foam and is one of the only rocks capable of floating on water for extended periods.
Field identification & locations
Identified by its fine vesicular texture, porous sponge-like cross section, extremely low weight, and lack of visible crystal boundaries under low magnification.
