igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black, aphanitic texture with fine-grained minerals, and dull to sub-metallic luster.
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Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black, aphanitic texture with fine-grained minerals, and dull to sub-metallic luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Used widely in construction as crushed aggregate, railroad ballast, dimension stone, and in the manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also makes up major volcanic features on the Moon and Mars.
Field identification & locations
Identify in the field by its dark, fine-grained matrix, dense weight, and occasional vesicular texture; found abundantly globally in volcanic provinces.
