igneous
Weathered vesicular volcanic rock (likely vesicular basalt or scoria)
Vesicular basalt; primarily plagioclase, pyroxene, and iron-rich oxides, with possible glass
AI-generated identification · may be incorrectGray-beige, strongly weathered, dull to weakly earthy luster, and numerous irregular vesicles. Basalt typically has Mohs hardness 5–6, fine-grained texture, no obvious cleavage, and specific gravity about 2.7–3.0; weathering may reduce density and hardness.
Identified More igneous →
Explore Weathered vesicular volcanic rock (likely vesicular basalt or scoria) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Gray-beige, strongly weathered, dull to weakly earthy luster, and numerous irregular vesicles. Basalt typically has Mohs hardness 5–6, fine-grained texture, no obvious cleavage, and specific gravity about 2.7–3.0; weathering may reduce density and hardness.
Formation & geological history
Formed when gas-rich basaltic lava cooled rapidly, trapping bubbles; the surface alteration and pale color reflect weathering. The exact geological age cannot be determined from the image and may range from ancient to recent volcanic activity.
Uses & applications
Used as aggregate, ballast, roadstone, and sometimes decorative landscaping stone; porous specimens are mainly collector pieces. Low gem value unless associated with attractive zeolite or mineral fillings.
Geological facts
The cavities are vesicles, produced by escaping volcanic gases rather than fossils. If the rock is unusually light and floats, it could instead be pumice; this specimen appears denser and more basaltic.
Field identification & locations
Common in volcanic regions, including Hawaii, Iceland, the Pacific Northwest, India, and oceanic islands. Field identification involves testing density, examining fine dark groundmass, and distinguishing vesicles from sedimentary pores; a fresh broken surface would help.
