igneous
Pumice
Pumice, vesicular volcanic glass (typically silica-rich rhyolite or dacite composition)
AI-generated identification · may be incorrectLight tan-gray with abundant rounded gas vesicles and a rough, dull-to-glassy surface; chiefly volcanic glass with possible feldspar and quartz. Hardness is variable, about 5–6 Mohs for the glassy material; crystal structure is mostly amorphous, with low specific gravity.
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-gray with abundant rounded gas vesicles and a rough, dull-to-glassy surface; chiefly volcanic glass with possible feldspar and quartz. Hardness is variable, about 5–6 Mohs for the glassy material; crystal structure is mostly amorphous, with low specific gravity.
Formation & geological history
Forms when gas-rich lava erupts and cools rapidly, trapping bubbles in volcanic glass. It can form during eruptions of many ages; the specimen’s age and source cannot be determined from the image.
Uses & applications
Used as an abrasive, lightweight aggregate, horticultural soil additive, and in polishing and personal-care products; attractive pieces are collected.
Geological facts
Pumice can be buoyant enough to float temporarily, though it eventually becomes waterlogged.
Field identification & locations
The abundant pits and low-density, frothy texture are characteristic; common around volcanic regions worldwide. The image supports a pumice identification, but composition is not confirmed by testing.
