igneous
Pumice
Pumice
Hardness: 6 on Mohs scale; Color: White, grey, yellowish, brown, or pink; Luster: Earthy to silky; Crystal structure: Amorphous (volcanic glass with vesicular texture); Specific gravity: Less than 1.0 (floats on water)
- Hardness
- 6 on Mohs scale
- Color
- White, grey, yellowish, brown, or pink
- Luster
- Earthy to silky
Identified More igneous →
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Physical properties
Hardness: 6 on Mohs scale; Color: White, grey, yellowish, brown, or pink; Luster: Earthy to silky; Crystal structure: Amorphous (volcanic glass with vesicular texture); Specific gravity: Less than 1.0 (floats on water)
Formation & geological history
Formed from explosive volcanic eruptions where gas-rich felsic lava cools rapidly, causing gases to exsolve into bubbles that are trapped as the lava solidifies into glass.
Uses & applications
Used in lightweight construction aggregates, concrete, abrasive stones, horticulture as a soil conditioner, and personal care products like pumice stones for exfoliating skin.
Geological facts
Pumice is one of the very few rocks that can float on water due to its high density of trapped air bubbles.
Field identification & locations
Easily identified by its extremely light weight, pale color, and numerous visible gas vesicles (holes). Found worldwide in volcanic regions, particularly along destructive plate boundaries.
