igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull to submetallic luster, fine-grained aphanitic crystal structure, and a specific gravity around 2.9.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull to submetallic luster, fine-grained aphanitic crystal structure, and a specific gravity around 2.9.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed stone for road bases, concrete aggregate, and manufacturing of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust, underlying most ocean basins and forming massive geological features like the Columbia River Plateau.
Field identification & locations
Identified by its dark color, heavy weight, and fine-grained texture lacking visible crystals; commonly found in volcanic regions worldwide.
