igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, aphanitic or fine-grained texture, and dull to sub-metallic luster.
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, aphanitic or fine-grained texture, 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 extensively in construction as crushed aggregate, railroad ballast, dimension stone, and for manufacturing rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms massive features like the Columbia River Basalts.
Field identification & locations
Identify by its dark color, heavy weight, and fine-grained matrix; commonly found in volcanic regions worldwide.
