igneous
Likely basalt or other fine-grained volcanic rock
Basalt (tentative; image alone is insufficient for a firm identification)
AI-generated identification · may be incorrectDense, rounded, dull gray-brown specimen with a fine-grained appearance; basalt is mainly plagioclase and pyroxene, often with olivine, and has Mohs hardness about 6. It typically lacks visible cleavage and has an interlocking crystalline texture.
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Physical properties
Dense, rounded, dull gray-brown specimen with a fine-grained appearance; basalt is mainly plagioclase and pyroxene, often with olivine, and has Mohs hardness about 6. It typically lacks visible cleavage and has an interlocking crystalline texture.
Formation & geological history
Basalt forms when low-viscosity lava cools quickly at or near Earth’s surface; it occurs from ancient volcanic terrains to active lava flows, spanning billions of years in age.
Uses & applications
Basalt is widely used as crushed aggregate, road stone, and building stone; this small unpolished piece is mainly suitable for collecting.
Geological facts
The rounded edges and weathered surface may result from water transport or prolonged weathering, but neither can be confirmed from the photo.
Field identification & locations
Look for a hard, compact, fine-grained rock, commonly dark gray to black, sometimes with small holes or visible crystals. Basalt occurs worldwide in volcanic regions; a streak, fresh break, and close-up examination would help distinguish it from other rocks.
