igneous
Vesicular volcanic rock (likely scoria)
Scoria, a vesicular basaltic to andesitic volcanic rock
AI-generated identification · may be incorrectRough, dark gray rock with abundant rounded gas cavities (vesicles) and a dull to slightly glassy luster. Typically Mohs 5–6; composed mainly of plagioclase, pyroxene, and often olivine, with a fine-grained or glassy groundmass.
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Physical properties
Rough, dark gray rock with abundant rounded gas cavities (vesicles) and a dull to slightly glassy luster. Typically Mohs 5–6; composed mainly of plagioclase, pyroxene, and often olivine, with a fine-grained or glassy groundmass.
Formation & geological history
Forms when gas-rich lava cools rapidly at or near the surface, trapping bubbles. It commonly forms during recent or geologically young eruptions; the exact age cannot be determined from the image.
Uses & applications
Used as lightweight aggregate, drainage material, landscaping stone, and sometimes abrasive or decorative material.
Geological facts
The many holes are vesicles left by escaping volcanic gases; scoria is generally denser and darker than pumice.
Field identification & locations
Identify it by its dark color, rough texture, and numerous cavities; it is common around basaltic and andesitic volcanoes and cinder cones. The image alone cannot confirm composition, so vesicular basalt is another possibility.
