igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, aphanitic texture with fine-grained crystals, dull to sub-metallic luster.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, aphanitic texture with fine-grained crystals, dull to sub-metallic 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 widely in construction as crushed stone for road bases, concrete aggregate, and in landscaping materials.
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
Easily identified in the field by its dark color, heavy weight, and fine-grained texture lacking visible crystals; found globally in volcanic regions.
