igneous
Dark basalt or other fine-grained volcanic rock
Likely basalt; exact identification is not possible from the image alone
AI-generated identification · may be incorrectDark gray, dull to subtly sparkly, and apparently fine-grained; basalt is typically Mohs 5–6, with plagioclase and pyroxene in a chiefly feldspar-rich crystalline structure. Cleavage and specific gravity cannot be determined from the photo.
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Physical properties
Dark gray, dull to subtly sparkly, and apparently fine-grained; basalt is typically Mohs 5–6, with plagioclase and pyroxene in a chiefly feldspar-rich crystalline structure. Cleavage and specific gravity cannot be determined from the photo.
Formation & geological history
Basalt forms when low-silica lava cools at or near Earth’s surface, commonly during volcanic eruptions; its age depends on the source deposit.
Uses & applications
Basalt is widely used as crushed aggregate, road stone, and building material; this small piece is mainly suitable for collecting or educational display.
Geological facts
The specimen’s dark color and granular surface are consistent with basalt, but the image does not show diagnostic features well enough to confirm the rock type.
Field identification & locations
Look for a dense, dark, fine-grained texture and lack of visible large crystals; basalt is common in volcanic regions and ancient lava flows worldwide. A fresh broken surface and simple hardness or streak tests would help distinguish it from other dark rocks.
