igneous
Vesicular volcanic rock, likely scoria
Scoria; vesicular basaltic to andesitic volcanic rock
AI-generated identification · may be incorrectTypically dark gray, brown, or reddish with abundant irregular gas cavities, dull to slightly glassy luster, and no consistent cleavage; hardness about 5–6, specific gravity commonly 2.0–2.7. The specimen appears weathered and iron-oxidized, though the image alone cannot confirm its exact composition.
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Physical properties
Typically dark gray, brown, or reddish with abundant irregular gas cavities, dull to slightly glassy luster, and no consistent cleavage; hardness about 5–6, specific gravity commonly 2.0–2.7. The specimen appears weathered and iron-oxidized, though the image alone cannot confirm its exact composition.
Formation & geological history
Forms when gas-rich lava cools rapidly at or near the surface, commonly during basaltic or andesitic eruptions; generally Cenozoic or younger, though scoria occurs throughout geologic time.
Uses & applications
Used as lightweight aggregate, drainage material, landscaping stone, abrasives, and occasionally as a decorative or lapidary material; ordinary pieces have little jewelry value.
Geological facts
Its numerous vesicles are frozen gas bubbles formed as pressure dropped during eruption. Red, orange, and brown colors commonly result from oxidation of iron-bearing minerals.
Field identification & locations
Identify it by its rough, porous texture, low apparent density, and volcanic appearance; pumice is usually much lighter and more silica-rich. Common around cinder cones, lava fields, and volcanic islands worldwide.
