igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectMohs hardness 6, dark gray to black color, dull luster, aphanitic to vesicular crystal structure, specific gravity 2.8-3.0.
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Physical properties
Mohs hardness 6, dark gray to black color, dull luster, aphanitic to vesicular crystal structure, specific gravity 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity, mafic lava flows exposed at or very near the surface of a planet or moon.
Uses & applications
Used in construction, aggregate for roads, railroad ballast, and manufacturing of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also forms extensive continental flood basalts.
Field identification & locations
Identify by its dark, fine-grained matrix, sometimes featuring vesicular gas cavities. Commonly found worldwide in volcanic regions.
