igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, dull luster, aphanitic crystal structure, and high specific gravity.
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, dull luster, aphanitic crystal structure, and high specific gravity.
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, crushed stone for road bases, aggregate in concrete, and manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the ocean basins and also makes up extensive volcanic plains on the Moon and Mars.
Field identification & locations
Identify by its dark, fine-grained matrix and heavy feel; commonly found in volcanic regions worldwide.
