igneous
Vesicular volcanic rock, likely scoria
Scoria; predominantly basaltic composition (plagioclase, pyroxene, olivine, and volcanic glass)
AI-generated identification · may be incorrectDark gray-brown, highly vesicular, rough, and dull to weakly glassy; typically 5–6 Mohs, with no visible cleavage and low-to-moderate density. The irregular cavities formed from trapped gas bubbles; the rusty areas may reflect iron oxidation or weathering.
Identified More igneous →
Explore Vesicular volcanic rock, likely scoria in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark gray-brown, highly vesicular, rough, and dull to weakly glassy; typically 5–6 Mohs, with no visible cleavage and low-to-moderate density. The irregular cavities formed from trapped gas bubbles; the rusty areas may reflect iron oxidation or weathering.
Formation & geological history
An extrusive igneous rock formed when gas-rich basaltic lava rapidly cooled, commonly during late Pleistocene to Holocene volcanic eruptions. Its exact identity is uncertain from the photograph because the specimen may also include weathered tuff or attached volcanic material.
Uses & applications
Used as lightweight aggregate, landscaping stone, drainage material, abrasives, and occasionally as a decorative specimen; generally not suitable for high-strength construction.
Geological facts
Scoria differs from pumice by usually being darker, denser, and less likely to float. Vesicles may be elongated or interconnected, recording expanding volcanic gases during eruption.
Field identification & locations
Identify it by its abundant bubble holes, rough texture, dark color, and volcanic appearance; common around cinder cones and basaltic lava fields worldwide. A fresh broken surface and density test would improve identification.
