igneous
Vesicular basalt (scoria-like volcanic rock)
Vesicular basalt, primarily plagioclase feldspar, pyroxene, and sometimes olivine
AI-generated identification · may be incorrectDark gray to brown, highly porous, dull to slightly earthy luster, with abundant irregular vesicles; typically Mohs hardness 5–6 and no prominent cleavage. The weathered surface may show rusty iron-oxide staining.
Identified More igneous →
Explore Vesicular basalt (scoria-like volcanic rock) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark gray to brown, highly porous, dull to slightly earthy luster, with abundant irregular vesicles; typically Mohs hardness 5–6 and no prominent cleavage. The weathered surface may show rusty iron-oxide staining.
Formation & geological history
Forms when gas-rich basaltic lava cools rapidly at or near the surface, trapping bubbles; commonly Quaternary to Recent in age. Its strongly weathered, cavity-rich appearance may also reflect prolonged exposure or alteration.
Uses & applications
Used as lightweight aggregate, landscaping stone, abrasives, and occasionally decorative specimen material; generally limited jewelry value.
Geological facts
Vesicles are frozen gas bubbles, while elongated or irregular cavities may result from coalesced bubbles and later weathering. It differs from pumice because basaltic scoria is usually darker, denser, and less likely to float.
Field identification & locations
Identify by its dark mafic color, rough porous texture, and basalt-like density; common in volcanic fields, lava flows, cinder cones, and oceanic islands. Exact identification would benefit from a fresh interior, streak, density, and locality information.
