igneous
Basalt
Extrusive mafic igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black in color, aphanitic texture with a dull luster, and high specific gravity.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black in color, aphanitic texture with a dull luster, and high specific gravity.
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 extensively in construction as crushed aggregate, railroad ballast, and in the manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust, making up most of the ocean floor and major volcanic islands like Hawaii.
Field identification & locations
Identified by its dark, fine-grained appearance, high density, and occasional vesicular texture from trapped gas bubbles.
