igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, aphanitic to glassy luster, fine-grained crystal structure, specific gravity around 2.9.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, aphanitic to glassy luster, fine-grained crystal structure, specific gravity around 2.9.
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
Used extensively in construction as crushed aggregate, railroad ballast, dimension stone, and in the manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms famous geological formations like the Giant's Causeway.
Field identification & locations
Identified by its dense, dark, fine-grained appearance, often found in volcanic regions, oceanic crusts, and ancient lava flows worldwide.
