igneous
Vesicular volcanic rock (likely pumice)
Pumice, a highly vesicular volcanic glass, commonly rhyolitic to dacitic in composition
AI-generated identification · may be incorrectPale cream-white, dull to slightly vitreous, with abundant rounded and irregular gas cavities; typically Mohs 5–6, though porous pieces feel lightweight. The image suggests pumice, but color and texture alone cannot confirm it; pumice may float, while similar porous rocks such as tufa usually do not.
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Physical properties
Pale cream-white, dull to slightly vitreous, with abundant rounded and irregular gas cavities; typically Mohs 5–6, though porous pieces feel lightweight. The image suggests pumice, but color and texture alone cannot confirm it; pumice may float, while similar porous rocks such as tufa usually do not.
Formation & geological history
Forms when gas-rich, silica-rich lava erupts and cools rapidly, trapping bubbles in volcanic glass. It can form during eruptions of many ages and is deposited near volcanoes or carried by water and wind.
Uses & applications
Used as an abrasive, lightweight aggregate, horticultural soil additive, and in personal-care products; attractive pieces are kept as geological specimens.
Geological facts
Pumice’s extensive vesicles make it exceptionally lightweight, and large pumice rafts can drift across the ocean after eruptions.
Field identification & locations
Look for a glassy, very porous texture and unusually low weight; a float test can support identification but is not definitive. Common around volcanic regions, including Italy, Iceland, New Zealand, and the western United States.
