igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black in color, fine-grained aphanitic texture, and dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black in color, fine-grained aphanitic texture, and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction for crushed stone, aggregate, railroad ballast, and dimension stone.
Geological facts
Basalt is the most common rock type in the Earth's crust, forming the majority of oceanic crust and extraterrestrial volcanic provinces like those on the Moon and Mars.
Field identification & locations
Identify by its dark, dense, fine-grained appearance, often containing small visible crystals; found abundantly globally in volcanic regions and oceanic islands.
