igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, fine-grained aphanitic texture, vitreous to dull luster, specific gravity of 2.8-3.0.
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, fine-grained aphanitic texture, vitreous to dull luster, specific gravity of 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava flows exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed aggregate, railroad ballast, and dimension stone, as well as in manufacturing rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also makes up extensive volcanic plains on the Moon and Mars.
Field identification & locations
Identify by its dark, fine-grained matrix and vesicular texture containing tiny plagioclase feldspar and pyroxene crystals; found globally.
