igneous
Vesicular basalt (likely weathered lava rock)
Vesicular basalt, chiefly plagioclase and pyroxene with possible olivine; composition cannot be confirmed from the image
AI-generated identification · may be incorrectPale gray-beige, rough and porous with irregular cavities; typically dull to slightly glassy, Mohs hardness about 5–6, with no obvious cleavage. The holes are vesicles left by escaping gas; the specimen’s light color may reflect weathering or mineral coatings.
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Physical properties
Pale gray-beige, rough and porous with irregular cavities; typically dull to slightly glassy, Mohs hardness about 5–6, with no obvious cleavage. The holes are vesicles left by escaping gas; the specimen’s light color may reflect weathering or mineral coatings.
Formation & geological history
Forms when gas-rich basaltic lava cools quickly at or near the surface; vesicles may later acquire secondary minerals. Basalt is found in volcanic terrains of many ages, from recent flows to ancient provinces.
Uses & applications
Vesicular basalt is used as lightweight aggregate, landscaping stone, and occasionally in decorative or educational collections.
Geological facts
The cavities distinguish vesicular volcanic rock from many dense basalts; sufficiently abundant or large vesicles may lead to the term scoria, though this sample is not identifiable that specifically from the image.
Field identification & locations
Look for a fine-grained volcanic matrix containing rounded or irregular gas holes; common in lava fields and volcanic regions. A close inspection or hardness and streak tests would help confirm the identification.
