igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, aphanitic texture with a dull luster, and specific gravity around 2.8 to 3.0.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, aphanitic texture with a dull luster, and specific gravity around 2.8 to 3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Widely used in construction as crushed aggregate, in railroad ballast, and for 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 also makes up extensive volcanic features on the Moon and Mars.
Field identification & locations
Identified by its dense, dark, fine-grained matrix and often vesicular texture; found abundantly in volcanic regions worldwide.
