igneous
Dark gray, fine-grained rock fragment (possibly basalt)
Basalt (tentative identification; image alone cannot confirm)
AI-generated identification · may be incorrectDull, dark gray-green and fine-grained, with no visible crystals; basalt typically has Mohs hardness about 6, a dense texture, and no cleavage. The fragment’s rough, angular shape is consistent with broken rock.
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Physical properties
Dull, dark gray-green and fine-grained, with no visible crystals; basalt typically has Mohs hardness about 6, a dense texture, and no cleavage. The fragment’s rough, angular shape is consistent with broken rock.
Formation & geological history
If basalt, it formed when iron- and magnesium-rich lava cooled rapidly at or near Earth’s surface; basalt is common from recent volcanism through ancient geologic formations.
Uses & applications
Basalt is used as crushed aggregate, road stone, and building material; this small fragment has little practical or jewelry use.
Geological facts
Basalt is among Earth’s most abundant volcanic rocks and also occurs extensively on the Moon and Mars.
Field identification & locations
A dark, dense, fine-grained appearance supports basalt, but similar-looking rocks include amphibolite and other mafic stones; confirm with a fresh surface and mineral or laboratory testing. Basalt occurs worldwide in volcanic regions and flood-basalt provinces.
