igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and dull 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 heavily in construction as crushed stone for road bases, aggregate in concrete, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type on the Earth's crust, making up most of the oceanic floor and forming massive volcanic features like the Columbia River Basalts.
Field identification & locations
Identify in the field by its dark color and fine-grained texture; it is commonly found in volcanic regions and oceanic crusts worldwide.
