igneous
Dark mafic rock, possibly basalt
Likely basalt; precise identification is uncertain from the image
AI-generated identification · may be incorrectAppears dark gray to black and fine-grained, with a dull to weakly shiny surface. Basalt typically contains plagioclase and pyroxene, has Mohs hardness about 6, and lacks visible cleavage; the specimen’s scale and texture are unclear.
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Physical properties
Appears dark gray to black and fine-grained, with a dull to weakly shiny surface. Basalt typically contains plagioclase and pyroxene, has Mohs hardness about 6, and lacks visible cleavage; the specimen’s scale and texture are unclear.
Formation & geological history
Basalt forms when iron- and magnesium-rich lava cools at or near the surface; it occurs in geological settings ranging from recent eruptions to ancient volcanic provinces.
Uses & applications
Basalt is used as crushed aggregate, road stone, and building stone; distinctive pieces may be kept as specimens.
Geological facts
The pictured dark material could also be another mafic rock or a non-geological object; the image does not reveal diagnostic crystals or a reliable scale.
Field identification & locations
If it is basalt, look for a dense, fine-grained texture and, sometimes, tiny pale feldspar crystals or gas holes. Common sources include volcanic regions and ancient lava flows.
