igneous
Dark, vesicular volcanic rock (likely basaltic scoria)
Scoria; fine-grained basaltic rock composed chiefly of plagioclase, pyroxene, and possibly olivine
AI-generated identification · may be incorrectBlack to dark gray, rough and highly vesicular, with a dull to slightly glassy luster; hardness about 5–6 Mohs, no obvious cleavage, and relatively low density compared with massive basalt. The image is insufficient for confident mineral identification.
Identified More igneous →
Explore Dark, vesicular volcanic rock (likely basaltic scoria) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Black to dark gray, rough and highly vesicular, with a dull to slightly glassy luster; hardness about 5–6 Mohs, no obvious cleavage, and relatively low density compared with massive basalt. The image is insufficient for confident mineral identification.
Formation & geological history
Forms when gas-rich basaltic lava cools rapidly, trapping bubbles in the solidifying magma; commonly Quaternary to modern near cinder cones, lava flows, and volcanic fields. Exact age and composition require location and testing.
Uses & applications
Used as lightweight aggregate, drainage material, abrasive, landscaping stone, and occasionally as a lapidary or teaching specimen; generally not jewelry-grade.
Geological facts
Its abundant cavities distinguish scoria from dense basalt; if the specimen is unusually heavy, metallic, and magnetic, it could instead be an iron-rich slag or meteorite fragment, requiring testing.
Field identification & locations
Look for vesicles, a jagged texture, and a black-to-reddish volcanic surface; common worldwide in volcanic regions. A streak, magnet test, density measurement, and thin-section or XRF analysis would improve identification.
