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 low specific gravity around 2.9.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and low specific gravity around 2.9.
Formation & geological history
Formed by 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 aggregate, railroad ballast, dimension stone, and for manufacturing rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins, and it is also abundantly found on the Moon and Mars.
Field identification & locations
Identify in the field by its dark, dense, fine-grained appearance and frequent vesicular structure. It occurs globally in volcanic regions and oceanic crusts.
