igneous
Pumice
Pumice (Vesicular Felsic Igneous Rock)
Hardness: 6 (can scratch glass when sharp), Color: White, grey, yellowish, or brownish, Luster: Earthy to silky, Crystal structure: Amorphous (volcanic glass with vesicular texture), Specific gravity: <1 (floats on water)
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Physical properties
Hardness: 6 (can scratch glass when sharp), Color: White, grey, yellowish, or brownish, Luster: Earthy to silky, Crystal structure: Amorphous (volcanic glass with vesicular texture), Specific gravity: <1 (floats on water)
Formation & geological history
Formed from explosive volcanic eruptions where gas-rich felsic lava cools rapidly, trapping gas bubbles within the rock.
Uses & applications
Used in lightweight construction aggregates, abrasive soaps, personal care (pumice stones for skin), and horticulture.
Geological facts
Pumice is one of the only rocks that can float on water due to its high porosity and trapped gas bubbles.
Field identification & locations
Easily identified by its extremely low weight, pale color, and abundant small vesicles (holes). Found worldwide near active or ancient volcanic regions.
