igneous
Likely vesicular basalt (scoria)
Basaltic scoria; chiefly plagioclase, pyroxene, and olivine with vesicles
AI-generated identification · may be incorrectDark gray-green, dull to slightly glassy, highly vesicular, and fine-grained; estimated Mohs hardness 5–6, with no obvious cleavage. The rounded form may be naturally weathered or human-shaped, and the image is somewhat blurred.
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Physical properties
Dark gray-green, dull to slightly glassy, highly vesicular, and fine-grained; estimated Mohs hardness 5–6, with no obvious cleavage. The rounded form may be naturally weathered or human-shaped, and the image is somewhat blurred.
Formation & geological history
An extrusive volcanic rock formed when gas-rich basaltic lava cooled rapidly, trapping bubbles; commonly Quaternary to modern in age. It occurs in cinder cones, lava flows, and volcanic fields.
Uses & applications
Used as lightweight aggregate, landscaping stone, drainage material, abrasives, and sometimes decorative specimens; generally not a jewelry gemstone.
Geological facts
Scoria is less dense than ordinary basalt because of abundant gas cavities, though it is typically denser and darker than pumice. Green coloration may reflect olivine or weathering.
Field identification & locations
Look for a dark, rough, porous surface and a relatively low density; a streak, magnetism, and fresh broken surface can help distinguish it from slag. Common worldwide near basaltic volcanoes, including Iceland, Hawaii, Italy, Mexico, and the western United States.
