igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark black to gray color, aphanitic texture with fine-grained minerals, dull to submetallic luster, specific gravity around 2.8 to 3.0.
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Physical properties
Hardness of 6 on Mohs scale, dark black to gray color, aphanitic texture with fine-grained minerals, dull to submetallic luster, specific gravity around 2.8 to 3.0.
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 for crushed stone, road base, concrete aggregate, and in manufacturing dimension stone and rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also makes up extensive volcanic plains on the Moon and Mars.
Field identification & locations
Identify by its dark, fine-grained matrix and heavy weight; commonly found in volcanic regions, oceanic islands, and continental flood basalt provinces.
