igneous
Dark river-worn stone, likely basalt
Fine-grained basalt (tentative; exact identification requires examination)
AI-generated identification · may be incorrectDark gray to black, dull to weakly waxy luster, with pale mineral veins or scratches; hardness and crystal structure cannot be determined reliably from the photo. Rounded shape and surface suggest natural abrasion.
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Physical properties
Dark gray to black, dull to weakly waxy luster, with pale mineral veins or scratches; hardness and crystal structure cannot be determined reliably from the photo. Rounded shape and surface suggest natural abrasion.
Formation & geological history
If basalt, it formed when iron- and magnesium-rich lava cooled at or near Earth’s surface; its age and source are not identifiable from the image. The rounded form likely developed through transport and abrasion in water.
Uses & applications
Useful chiefly as a field or collection specimen; basalt is also used as aggregate, paving stone, and construction material.
Geological facts
The light lines may be mineral-filled fractures, but could also be surface scratches; a close-up or tests would help distinguish them.
Field identification & locations
The smooth, rounded outline is consistent with a river cobble. Basalt is common in volcanic regions worldwide; confirm with fresh-surface texture and mineral tests before relying on this identification.
