igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark black to gray color, dull luster, fine-grained aphanitic texture, and specific gravity around 2.8-3.0.
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Physical properties
Hardness of 6 on the Mohs scale, dark black to gray color, dull luster, fine-grained aphanitic texture, 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 for crushed stone, railroad ballast, aggregate in concrete, and manufacturing of stone wool insulation.
Geological facts
Basalt is the most common rock type on the Earth's oceanic crust and also makes up extensive volcanic plains on the Moon and Mars.
Field identification & locations
Identify by its dark, fine-grained appearance, heavy weight, and common occurrence in volcanic regions worldwide.
