igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness is 6 on the Mohs scale. Colors range from dark gray to black with a fine-grained aphanitic texture.
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Physical properties
Hardness is 6 on the Mohs scale. Colors range from dark gray to black with a fine-grained aphanitic texture.
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 as crushed aggregate, railroad ballast, and dimension stone.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and is also found on the Moon and Mars.
Field identification & locations
Identified by its dark color and fine-grained matrix, often containing visible vesicles or holes left by escaping gas bubbles.
