igneous
Likely vesicular basalt (scoria)
Basaltic volcanic rock, chiefly plagioclase, pyroxene, and possibly olivine
AI-generated identification · may be incorrectGray-beige, fine-grained and strongly vesicular, with dull to slightly earthy luster; hardness about 5–6, no obvious cleavage, and moderate density reduced by gas cavities. The texture is consistent with scoria or porous basalt, though the image is not sufficient for precise identification.
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Physical properties
Gray-beige, fine-grained and strongly vesicular, with dull to slightly earthy luster; hardness about 5–6, no obvious cleavage, and moderate density reduced by gas cavities. The texture is consistent with scoria or porous basalt, though the image is not sufficient for precise identification.
Formation & geological history
Forms when iron- and magnesium-rich lava cools rapidly at or near the surface, trapping expanding gas bubbles; commonly Quaternary to modern in volcanic fields. The specimen may also be weathered volcanic cinder.
Uses & applications
Used as lightweight aggregate, landscaping stone, drainage material, abrasives, and occasionally aquarium décor; porous pieces have limited jewelry value.
Geological facts
Scoria is generally darker and redder than pumice because it retains abundant iron-bearing minerals. Its vesicles are irregular and connected less extensively than those of pumice.
Field identification & locations
Look for abundant rounded to elongated holes, a rough frothy surface, and basaltic dark minerals; it should not fizz with dilute acid. Common in Hawaii, Iceland, western North America, Italy, and other volcanic regions.
