igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, dull to sub-metallic luster, fine-grained aphanitic crystal structure, and high specific gravity.
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, dull to sub-metallic luster, fine-grained aphanitic crystal structure, and high specific gravity.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed aggregate for roads, railroad ballast, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also forms extensive continental flood basalt provinces.
Field identification & locations
Identified by its dark, fine-grained matrix and vesicular texture; found abundantly worldwide in volcanic regions and ocean floors.
