igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black, fine-grained aphanitic texture with dense specific gravity around 2.9.
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Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black, fine-grained aphanitic texture with dense specific gravity around 2.9.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface.
Uses & applications
Extensively used in construction as crushed stone for road bases, concrete aggregate, and in manufacturing fiber.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also forms major volcanic features on the Moon and Mars.
Field identification & locations
Identify by its dark, dense, fine-grained appearance, often found in volcanic regions, riverbeds, and as glacial erratics.
