igneous
Dark rock fragment, possibly basalt
Unidentified mafic volcanic rock; basalt is a tentative visual identification
AI-generated identification · may be incorrectSmall, dark, fine-grained-looking fragment with a tan-brown exposed end; hardness, luster, and crystal structure cannot be determined reliably from the image.
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Physical properties
Small, dark, fine-grained-looking fragment with a tan-brown exposed end; hardness, luster, and crystal structure cannot be determined reliably from the image.
Formation & geological history
If basalt, it formed when iron- and magnesium-rich lava cooled at or near Earth’s surface; its age and source cannot be established from the image.
Uses & applications
Basalt is used as aggregate, paving stone, and building stone; this fragment’s small size suggests no practical use beyond collecting.
Geological facts
The dark exterior and lighter broken surface are consistent with many rocks and are not diagnostic of basalt.
Field identification & locations
A fresh break, visible grain size, streak, and hardness test would help identify it; basalt is widespread in volcanic regions worldwide.
