igneous
Vesicular volcanic rock (likely scoria)
Scoria; vesicular basaltic to andesitic volcanic rock
AI-generated identification · may be incorrectRough, porous tan-brown rock with abundant irregular cavities and a dull, earthy surface. Typically composed of plagioclase, pyroxene, and volcanic glass; hardness about 5–6 Mohs, with no regular cleavage. The photo alone does not establish its exact composition or color when fresh.
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Physical properties
Rough, porous tan-brown rock with abundant irregular cavities and a dull, earthy surface. Typically composed of plagioclase, pyroxene, and volcanic glass; hardness about 5–6 Mohs, with no regular cleavage. The photo alone does not establish its exact composition or color when fresh.
Formation & geological history
Forms when gas-rich lava cools rapidly, trapping bubbles as vesicles; generally associated with relatively young volcanic eruptions, though no age can be determined from the image.
Uses & applications
Used as lightweight aggregate, landscaping stone, drainage material, and occasionally in construction; specimens may be collected for their vesicular texture.
Geological facts
Scoria is less vesicular and usually denser than pumice, and commonly has darker colors; weathering can make it look tan or brown.
Field identification & locations
Look for a lightweight, rough volcanic texture with many cavities and a lack of sedimentary layering. Scoria occurs near cinder cones and basaltic lava flows in volcanic regions worldwide.
