igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and high density.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and high density.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Extensively used in construction as crushed aggregate, railroad ballast, dimension stone, and in manufacturing rock wool insulation.
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 in the field by its dark, dense, fine-grained appearance; commonly found globally in volcanic regions and oceanic islands.
