igneous
Dark, vesicular volcanic rock (likely scoria)
Scoria, a vesicular basaltic to andesitic volcanic rock
AI-generated identification · may be incorrectDark gray to black, rough and porous, with scattered pale mineral grains; typically fine-grained, with no visible cleavage. Hardness and density vary with composition and porosity; the image alone cannot establish them.
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Physical properties
Dark gray to black, rough and porous, with scattered pale mineral grains; typically fine-grained, with no visible cleavage. Hardness and density vary with composition and porosity; the image alone cannot establish them.
Formation & geological history
Forms when gas-rich lava cools quickly, trapping bubbles. It is generally geologically young, though scoria occurs in volcanic deposits of many ages.
Uses & applications
Used as lightweight aggregate, landscaping stone, drainage material, and sometimes as a decorative specimen.
Geological facts
Scoria’s cavities are gas bubbles preserved as the lava solidified; it is denser and less glassy than pumice in many cases.
Field identification & locations
Look for a dark volcanic groundmass and abundant irregular cavities; pale specks may be feldspar or other minerals. Common near basaltic volcanoes and cinder cones; the pictured pieces are too small and context-limited for a definitive identification.
