igneous
Pumice
Pumice
Hardness: 6 on the Mohs scale; Color: White, yellowish, grey, brown; Luster: Earthy to silky; Crystal structure: Amorphous (volcanic glass); Specific gravity: Less than 1 (it floats on water due to high porosity)
- Hardness
- 6 on the Mohs scale
- Color
- White, yellowish, grey, brown
- Luster
- Earthy to silky
Identified More igneous →
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Physical properties
Hardness: 6 on the Mohs scale; Color: White, yellowish, grey, brown; Luster: Earthy to silky; Crystal structure: Amorphous (volcanic glass); Specific gravity: Less than 1 (it floats on water due to high porosity)
Formation & geological history
Formed from explosive volcanic eruptions where gas-rich frothy felsic or intermediate lava cools rapidly, trapping gas bubbles within the glassy matrix.
Uses & applications
Used in abrasive materials, lightweight concrete, horticulture as a soil conditioner, and for personal care (exfoliating stones).
Geological facts
Pumice is one of the very few rocks that can float on water because of its vesicular structure containing trapped air bubbles.
Field identification & locations
Easily identified by its extremely low density, light weight, vesicular (foamy/bubbly) texture, and pale color. Found worldwide near active or ancient volcanic regions.
