igneous
Vesicular basalt (likely scoriaceous basalt)
Scoriaceous basalt; primarily calcium-rich plagioclase, pyroxene, and olivine with iron-oxide alteration
AI-generated identification · may be incorrectDark reddish-brown, highly vesicular, rough, and dull to earthy with tiny crystalline grains; hardness about 5–6 Mohs, no prominent cleavage, and typically moderate density reduced by gas cavities. The red color commonly reflects oxidation of iron-bearing minerals.
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Physical properties
Dark reddish-brown, highly vesicular, rough, and dull to earthy with tiny crystalline grains; hardness about 5–6 Mohs, no prominent cleavage, and typically moderate density reduced by gas cavities. The red color commonly reflects oxidation of iron-bearing minerals.
Formation & geological history
An extrusive volcanic rock formed when gas-rich basaltic lava cooled rapidly at or near the surface; the specimen may be geologically young, though similar textures occur in basalts of any age. Oxidation and weathering produced the reddish-brown surface.
Uses & applications
Used as lightweight aggregate, landscaping stone, drainage material, and occasionally abrasive or decorative stone; generally not a jewelry material. Sound, dense basalt is also widely used for road metal and construction aggregate.
Geological facts
The holes are vesicles—gas bubbles trapped during lava cooling—and distinguish scoria from ordinary massive basalt. The unusually red, weathered appearance can resemble oxidized volcanic cinder.
Field identification & locations
Identify it by its rough vesicular texture, volcanic appearance, heavy feel relative to size, and lack of visible sedimentary layering; a steel nail generally will not scratch fresh basalt easily. Common in volcanic fields, cinder cones, lava flows, and basaltic islands worldwide.
