igneous
Vesicular volcanic rock, likely scoria
Scoria; predominantly basaltic or andesitic volcanic glass with plagioclase, pyroxene, and possible iron oxides
AI-generated identification · may be incorrectHardness about 5–6 Mohs; pinkish-brown to gray, dull to slightly glassy, highly vesicular, and very lightweight for its size. The irregular cavities formed by trapped gas; it has no consistent cleavage and typically low-to-moderate specific gravity.
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Physical properties
Hardness about 5–6 Mohs; pinkish-brown to gray, dull to slightly glassy, highly vesicular, and very lightweight for its size. The irregular cavities formed by trapped gas; it has no consistent cleavage and typically low-to-moderate specific gravity.
Formation & geological history
Forms when gas-rich basaltic to andesitic lava cools rapidly near a volcanic vent, preserving abundant bubbles. It is generally geologically young, ranging from recent eruptions to rocks of any Cenozoic volcanic age.
Uses & applications
Used as lightweight aggregate, drainage material, abrasive, landscaping stone, and sometimes in horticulture or decorative collections. This specimen has modest commercial value.
Geological facts
Scoria is denser and usually darker than pumice because its bubbles are partly enclosed and its melt contains more iron and magnesium. The rusty coloration commonly reflects oxidation of iron-bearing minerals.
Field identification & locations
Identify it by its rough, frothy texture, angular vesicles, volcanic appearance, and light weight; unlike pumice, it usually does not float. Common around cinder cones and basaltic lava fields worldwide.
