igneous
Pumice
Pumice (volcanic glass foam)
AI-generated identification · may be incorrectHardness is 6 on the Mohs scale. Colors range from white, grey, to cream with a dull luster and extremely porous, vesicular structure that allows it to float on water.
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Physical properties
Hardness is 6 on the Mohs scale. Colors range from white, grey, to cream with a dull luster and extremely porous, vesicular structure that allows it to float on water.
Formation & geological history
Formed during explosive volcanic eruptions when frothy, gas-rich lava rapidly cools and depressurizes, trapping gas bubbles within the glassy matrix.
Uses & applications
Widely used in lightweight concrete, abrasive soaps, cosmetic exfoliating stones, and horticulture for soil aeration.
Geological facts
Pumice is one of the only rocks that can float on water due to its high concentration of trapped air bubbles. It has been used since Roman times as a construction aggregate and abrasive.
Field identification & locations
Easily identified by its very light weight, pale color, and abundance of small holes or vesicles. Found globally near regions of recent volcanic activity, especially in Italy, the USA, and Turkey.
