igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull luster, composed mainly of plagioclase feldspar and pyroxene.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull luster, composed mainly of plagioclase feldspar and pyroxene.
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 stone for road bases, railroad ballast, and in the production of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the ocean basins and also forms massive volcanic features like the Giant's Causeway.
Field identification & locations
Identified by its dark color, fine-grained texture, and heavy weight. Found abundantly worldwide in volcanic regions and oceanic crusts.
