igneous
Pumice
Pumice (Volcanic Rock / Glass Froth)
Mohs hardness of 6 on fresh surfaces, extremely light with high porosity, often floats on water, color ranges from white, grey, yellowish, to brown, glassy luster, vesicular texture.
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Physical properties
Mohs hardness of 6 on fresh surfaces, extremely light with high porosity, often floats on water, color ranges from white, grey, yellowish, to brown, glassy luster, vesicular texture.
Formation & geological history
Formed from explosive volcanic eruptions where gas-rich, felsic to intermediate magma cools rapidly, trapping gas bubbles within the solidifying glass matrix.
Uses & applications
Used in abrasive materials, personal care products like pumice stones for skin, lightweight concrete aggregate, horticulture, and washing denim jeans.
Geological facts
Pumice is one of the only rocks that can float on water due to its high concentration of trapped gas bubbles. It has been used since antiquity for exfoliating skin and as an abrasive.
Field identification & locations
Easily identified by its extremely low density, light weight, and abundance of small holes (vesicles). Commonly found near active or historical volcanic regions worldwide.
