igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull to sub-with a fine-grained aphanitic crystal structure.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull to sub-with a fine-grained aphanitic crystal structure.
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
Commonly 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 color, fine-grained texture, and high density; found worldwide in volcanic regions and ocean floors.
