igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, aphanitic texture, and dull luster.
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, aphanitic texture, and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in magnesium and iron exposed at or very near the surface of a planet or moon.
Uses & applications
Used extensively in construction as crushed aggregate, for railroad ballast, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust and also makes up most of the ocean floor as well as the lunar maria.
Field identification & locations
Easily identified by its dark, fine-grained matrix and vesicular texture caused by trapped gas bubbles; found globally in volcanic provinces.
