igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, dull to sub-to-glassy luster, fine-grained aphanitic crystal structure.
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, dull to sub-to-glassy luster, fine-grained aphanitic crystal structure.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or very near the surface of a planet or moon.
Uses & applications
Used extensively in construction as crushed stone for road bases, concrete aggregate, and in manufacturing stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms prominent geological formations like the Giant's Causeway.
Field identification & locations
Identify by its dark color and very fine-grained texture; found abundantly in volcanic regions worldwide.
