igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectMohs hardness of 6, dark gray to black color, aphanitic to glassy luster, fine-grained crystal structure, specific gravity around 2.8 to 3.0.
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Physical properties
Mohs hardness of 6, dark gray to black color, aphanitic to glassy luster, fine-grained crystal structure, specific gravity around 2.8 to 3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or very near the surface of a planet or moon.
Uses & applications
Widely used in construction for road aggregates, railroad ballast, building stone, and in the production of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust, making up most of the ocean floor and large volcanic provinces like the Deccan Traps.
Field identification & locations
Identified by its dark, fine-grained groundmass and dense nature. Commonly found globally in oceanic crust and volcanic regions.
