igneous
Dark vesicular volcanic rock, likely scoria
Scoria; predominantly basaltic or andesitic volcanic glass with plagioclase, pyroxene, and olivine
AI-generated identification · may be incorrectTypically black to reddish-brown, highly porous, rough, and dull to slightly glassy; hardness about 5–6 Mohs, with no consistent cleavage. The specimen appears dense and irregularly vesicular, though the image alone cannot confirm its exact composition.
Identified More igneous →
Explore Dark vesicular volcanic rock, likely scoria in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically black to reddish-brown, highly porous, rough, and dull to slightly glassy; hardness about 5–6 Mohs, with no consistent cleavage. The specimen appears dense and irregularly vesicular, though the image alone cannot confirm its exact composition.
Formation & geological history
Forms when gas-rich basaltic to andesitic lava rapidly cools, trapping bubbles; commonly associated with young volcanic cones, lava flows, and cinder deposits, generally Quaternary to modern in age.
Uses & applications
Used as lightweight aggregate, drainage and landscaping stone, abrasive material, and occasionally in decorative rockwork. It has little gemstone value.
Geological facts
Scoria is generally darker and denser than pumice because it contains fewer and smaller connected vesicles. Its rusty areas commonly result from oxidation of iron-bearing minerals.
Field identification & locations
Identify it by its black or reddish color, frothy texture, rough surface, and relatively high density compared with pumice; common around volcanic fields and cinder cones. A fresh broken surface and magnetic response can help distinguish basaltic scoria.
