igneous
Pumice
Vesicular volcanic rock, primarily silica-rich volcanic glass (commonly rhyolitic or dacitic)
AI-generated identification · may be incorrectLight tan, highly vesicular, rough, dull to slightly glassy surface; Mohs hardness about 5–6, no cleavage, and unusually low density—often floats in water. The cavities formed by trapped volcanic gas are the key diagnostic feature.
Identified More igneous →
Explore Pumice in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Light tan, highly vesicular, rough, dull to slightly glassy surface; Mohs hardness about 5–6, no cleavage, and unusually low density—often floats in water. The cavities formed by trapped volcanic gas are the key diagnostic feature.
Formation & geological history
Forms when gas-rich lava erupts explosively and cools rapidly, preserving abundant bubbles; specimens may range from recent volcanic material to deposits millions of years old.
Uses & applications
Used as an abrasive, exfoliant, polishing medium, lightweight aggregate, horticultural amendment, and in concrete or landscaping.
Geological facts
Pumice is not a mineral but a natural volcanic glass. Its pores can make it buoyant, though waterlogged pieces may eventually sink.
Field identification & locations
Identify it by its low weight, frothy texture, sharp pores, and lack of organized crystals; common sources include Italy, Turkey, Greece, the western United States, and New Zealand.
