igneous
Dark rock fragment, possibly basalt
Undetermined; possibly basalt (fine-grained mafic volcanic rock)
AI-generated identification · may be incorrectDark gray to black, rough and irregular with a dull to slightly glassy surface. Hardness and crystal structure cannot be reliably determined from the image; basalt typically has Mohs hardness around 6 and fine crystals too small to see.
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Physical properties
Dark gray to black, rough and irregular with a dull to slightly glassy surface. Hardness and crystal structure cannot be reliably determined from the image; basalt typically has Mohs hardness around 6 and fine crystals too small to see.
Formation & geological history
If basalt, it formed when iron- and magnesium-rich lava cooled at or near Earth’s surface; basalt occurs from many geological periods. The image alone does not establish the specimen’s identity or age.
Uses & applications
Basalt is widely used as crushed aggregate, paving stone, and construction material; this small fragment has no apparent commercial value.
Geological facts
Basalt is one of Earth’s most abundant volcanic rocks and forms much of the ocean floor.
Field identification & locations
The specimen appears rock-like, but its dark color and shape are not enough to confirm basalt; inspect a fresh break for fine grains and test hardness and streak. Dark fragments may also be other rocks or industrial material.
