igneous
Basalt flake
Aphanitic mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, microcrystalline to cryptocrystalline structure, no distinct cleavage.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, microcrystalline to cryptocrystalline structure, no distinct cleavage.
Formation & geological history
Formed from the rapid cooling of low-viscosity, iron- and magnesium-rich lava flows at the Earth's surface.
Uses & applications
Used primarily in aggregate for construction, road building, and occasionally as dimension stone.
Geological facts
Basalt is the most common rock type in the Earth's crust, forming the majority of oceanic crust and large volcanic provinces.
Field identification & locations
Identify by its dark color, fine-grained texture, and frequent association with volcanic terrains.
