igneous
Vesicular basalt (lava rock)
Vesicular basalt; chiefly plagioclase, pyroxene, and often olivine
AI-generated identification · may be incorrectDark gray-brown, fine-grained volcanic rock with abundant rounded gas-bubble cavities (vesicles); typically Mohs 5–6, dull to slightly glassy, with no obvious cleavage. Exact composition and density cannot be confirmed from the photo.
Identified More igneous →
Explore Vesicular basalt (lava rock) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark gray-brown, fine-grained volcanic rock with abundant rounded gas-bubble cavities (vesicles); typically Mohs 5–6, dull to slightly glassy, with no obvious cleavage. Exact composition and density cannot be confirmed from the photo.
Formation & geological history
Formed when gas-rich basaltic lava cooled rapidly at or near the surface, trapping bubbles. Its age is indeterminable from the image; vesicular basalt occurs in volcanic rocks of many ages.
Uses & applications
Used as landscaping stone, lightweight aggregate, drainage material, and sometimes in construction; porous pieces may be collected or used decoratively.
Geological facts
The holes are vesicles left by escaping volcanic gases; if later filled with minerals, they are called amygdales.
Field identification & locations
Look for a dark, fine-grained groundmass with abundant cavities and no visible layering. Common near basaltic lava flows and volcanic fields worldwide; the image alone cannot establish a specific locality.
