igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava exposed at or very near the Earth's surface.
Uses & applications
Used widely in construction for crushed stone, aggregate in concrete, railroad ballast, and manufacturing stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms extensive volcanic plateaus.
Field identification & locations
Easily identified by its dark, dense, fine-grained matrix and vesicular texture; highly abundant in volcanic regions worldwide.
