igneous
Dark mafic rock, possibly basalt
Basalt (provisional identification; exact rock type cannot be confirmed from the image)
AI-generated identification · may be incorrectDark brown to black, rough and massive, with a fine-grained appearance; likely Mohs hardness 5–6 and dull to slightly vitreous luster. Individual crystals and cleavage are not distinguishable in the photo.
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Physical properties
Dark brown to black, rough and massive, with a fine-grained appearance; likely Mohs hardness 5–6 and dull to slightly vitreous luster. Individual crystals and cleavage are not distinguishable in the photo.
Formation & geological history
Basalt forms when iron- and magnesium-rich lava cools rapidly at or near Earth’s surface; specimens may range from recent to billions of years old.
Uses & applications
Basalt is widely used as crushed aggregate, road stone, and construction material; this small specimen is mainly suitable for collecting.
Geological facts
Basalt is among Earth’s most abundant volcanic rocks and also forms much of the oceanic crust.
Field identification & locations
A dark color and dense, fine-grained texture are consistent with basalt, but a closer view or tests are needed to distinguish it from other dark rocks. Basalt is common in volcanic regions worldwide.
