igneous
Vesicular basalt (weathered lava rock)
Basalt, chiefly plagioclase and pyroxene with possible olivine; vesicles are gas-bubble cavities
AI-generated identification · may be incorrectGray to dark gray, fine-grained and porous with irregular holes; typically Mohs 5–6, dull to slightly glassy, with no obvious cleavage. The photo suggests weathered vesicular lava, though exact identification needs close inspection.
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Physical properties
Gray to dark gray, fine-grained and porous with irregular holes; typically Mohs 5–6, dull to slightly glassy, with no obvious cleavage. The photo suggests weathered vesicular lava, though exact identification needs close inspection.
Formation & geological history
Forms when gas-rich basaltic lava cools rapidly at or near the surface; commonly Cenozoic or younger, but basalt occurs across geological ages.
Uses & applications
Used as aggregate, landscaping stone, and occasionally as a lightweight construction material; this rough specimen has little jewelry value.
Geological facts
Its holes are vesicles left by gas escaping from cooling lava; later minerals can sometimes fill them to form amygdales.
Field identification & locations
Look for a dark, fine-grained groundmass and rounded or irregular cavities; common in volcanic regions worldwide. The pale color here may reflect strong weathering or mineral coatings.
