igneous
Fine-grained gray rock, likely basalt
Basalt (probable; exact identification requires a clearer view)
AI-generated identification · may be incorrectDark gray, dull, fine-grained and irregular, with no obvious crystals visible. Basalt is typically composed mainly of plagioclase and pyroxene, sometimes olivine; hardness about 6 on Mohs scale and specific gravity around 2.8–3.0.
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Physical properties
Dark gray, dull, fine-grained and irregular, with no obvious crystals visible. Basalt is typically composed mainly of plagioclase and pyroxene, sometimes olivine; hardness about 6 on Mohs scale and specific gravity around 2.8–3.0.
Formation & geological history
Basalt forms when lava cools rapidly at or near Earth’s surface; it occurs in volcanic regions and ranges from recent to billions of years old.
Uses & applications
Commonly used as crushed aggregate for roads and concrete, construction stone, and occasionally as a decorative or collectible specimen.
Geological facts
Basalt is one of Earth’s most abundant volcanic rocks and also forms much of the ocean floor.
Field identification & locations
A dense, dark, fine-grained texture supports basalt identification, but this small, blurry specimen could be another gray rock. Basalt is widespread in volcanic areas worldwide; a fresh broken surface and magnification help confirm it.
