igneous
Weathered vesicular volcanic rock, likely pumice or scoria
Vesicular rhyolitic pumice or basaltic scoria; exact identification requires a clearer image and tests
AI-generated identification · may be incorrectLight tan-gray, highly porous, and rough with a dull to slightly earthy luster; vesicles are gas cavities in volcanic glass or fine-grained lava. Hardness is roughly 5–6 Mohs, though weathering may make it friable; cleavage is absent and specific gravity is low to moderate.
Identified More igneous →
Explore Weathered vesicular volcanic rock, likely pumice or scoria in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Light tan-gray, highly porous, and rough with a dull to slightly earthy luster; vesicles are gas cavities in volcanic glass or fine-grained lava. Hardness is roughly 5–6 Mohs, though weathering may make it friable; cleavage is absent and specific gravity is low to moderate.
Formation & geological history
Formed when gas-rich magma erupted and rapidly cooled, trapping bubbles; it is geologically young relative to most crustal rocks and may originate from explosive volcanic eruptions or lava fountains.
Uses & applications
Pumice is used as an abrasive, lightweight aggregate, horticultural medium, and concrete additive; scoria is used mainly as landscaping stone, road aggregate, and lightweight fill. Collecting value is usually minimal.
Geological facts
Pumice can float when its connected pores contain air, while denser scoria generally sinks. The specimen’s pale color favors pumice, but its irregular shape and apparent weathering prevent confident distinction.
Field identification & locations
Look for abundant rounded vesicles, low density, and a glassy or fine-grained texture; test streak, weight, and whether it floats, but avoid damaging a valuable specimen. Common sources include volcanic regions worldwide, especially Italy, Iceland, Mexico, and the western United States.
