igneous
Pumice
Pumice (Volcanic Rock)
Hardness: 6 on the Mohs scale, Color: White, grey, cream, or yellowish, Luster: Dull, Structure: Vesicular (full of tiny gas bubbles), Specific Gravity: Less than 1.0 (floats on water)
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Physical properties
Hardness: 6 on the Mohs scale, Color: White, grey, cream, or yellowish, Luster: Dull, Structure: Vesicular (full of tiny gas bubbles), Specific Gravity: Less than 1.0 (floats on water)
Formation & geological history
Formed from explosive volcanic eruptions where gas-rich frothy felsic lava cools rapidly, preventing crystal formation and trapping gas bubbles.
Uses & applications
Used in lightweight concrete, abrasive products, pumice stones for personal care, horticulture as a soil amendment, and stonewashing jeans.
Geological facts
Pumice is one of the only rocks that can float on water due to its extremely high porosity and trapped air bubbles.
Field identification & locations
Easily identified by its extremely light weight, pale color, rough texture, and visible vesicular holes. Found globally near active or past volcanic regions.
