igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 5-6 on Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull luster.
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Physical properties
Hardness 5-6 on Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface.
Uses & applications
Used extensively in construction as crushed stone for road bases, concrete aggregate, and dimension stone.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also forms massive volcanic structures like the Giant's Causeway.
Field identification & locations
Identify by its dark color, fine-grained texture, and heavy weight; found globally in volcanic regions and ocean floors.
