igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 5-6 on the Mohs scale, dark gray to black in color, aphanitic texture with a dull luster, and specific gravity around 2.8-3.0.
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Physical properties
Hardness of 5-6 on the Mohs scale, dark gray to black in color, aphanitic texture with a dull luster, and specific gravity around 2.8-3.0.
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, concrete aggregate, 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 is also found abundantly in volcanic regions of East Africa.
Field identification & locations
Identify by its dark, fine-grained groundmass, often with small visible olivine or pyroxene phenocrysts; very common globally and locally consistent with the East African Rift region.
