igneous
Vesicular volcanic rock (likely pumice)
Pumice, a highly vesicular volcanic glass; exact identification is uncertain from the image
AI-generated identification · may be incorrectPale gray to white, porous, with many rounded gas cavities and a dull to slightly glassy surface. Pumice is commonly about 5–6 on the Mohs scale, has no regular crystal structure or cleavage, and is unusually lightweight; the specimen’s apparent weight cannot be assessed from the photo.
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Physical properties
Pale gray to white, porous, with many rounded gas cavities and a dull to slightly glassy surface. Pumice is commonly about 5–6 on the Mohs scale, has no regular crystal structure or cleavage, and is unusually lightweight; the specimen’s apparent weight cannot be assessed from the photo.
Formation & geological history
Forms when gas-rich lava cools rapidly during explosive eruptions, trapping bubbles in volcanic glass. Its age and source cannot be determined visually.
Uses & applications
Pumice is used as an abrasive, in polishing and exfoliating products, and as a lightweight additive in concrete and horticultural mixes.
Geological facts
Pumice can be buoyant enough to travel long distances floating on water, though this small specimen’s porosity and density are unknown.
Field identification & locations
Look for a lightweight, frothy texture with abundant cavities; volcanic scoria is a similar, often darker and denser alternative. Pumice occurs near explosive volcanic deposits worldwide.
