igneous
Likely basalt or another dark, fine-grained volcanic rock
Basalt (tentative; composition cannot be confirmed from the image)
AI-generated identification · may be incorrectA small, opaque, dark gray-black fragment with a matte surface and no visible crystals. Basalt typically has Mohs hardness 5–6, a fine-grained texture, and specific gravity around 2.8–3.0.
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Physical properties
A small, opaque, dark gray-black fragment with a matte surface and no visible crystals. Basalt typically has Mohs hardness 5–6, a fine-grained texture, and specific gravity around 2.8–3.0.
Formation & geological history
Basalt forms when iron- and magnesium-rich lava cools quickly at or near Earth’s surface; it occurs from ancient to recent volcanic settings.
Uses & applications
Basalt is widely used as crushed aggregate, road stone, and building material; this small fragment has little practical or jewelry use.
Geological facts
Fine-grained basalt can look nearly featureless because its crystals are too small to see without magnification.
Field identification & locations
Look for a dense, hard, dark rock that may contain tiny crystals or gas-bubble holes; common sources include lava flows and volcanic regions. The image alone does not establish the identification.
