igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale; dark gray to black color; aphanitic (fine-grained) texture; subconchoidal fracture with high density.
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Physical properties
Hardness 6 on Mohs scale; dark gray to black color; aphanitic (fine-grained) texture; subconchoidal fracture with high density.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the surface of a planet or moon.
Uses & applications
Widely used in construction as crushed aggregate for roads, railroad ballast, and in the production of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also makes up extensive volcanic formations on the Moon and Mars.
Field identification & locations
Identify by its dark, fine-grained appearance and heavy weight relative to size. Found worldwide in volcanic provinces and oceanic islands.
