igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale; dark gray to black color; aphanitic to porphyritic texture with dull luster; specific gravity around 2.8-3.0.
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Physical properties
Hardness 6 on Mohs scale; dark gray to black color; aphanitic to porphyritic texture with dull luster; specific gravity around 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity, iron- and magnesium-rich lava flows at the Earth's surface.
Uses & applications
Widely used in construction, crushed stone for road bases, concrete aggregate, and manufacturing of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust, making up most of the ocean floor and significant volcanic provinces worldwide.
Field identification & locations
Identify by its dark, fine-grained groundmass and heavy weight. Found globally in volcanic regions and oceanic crusts.
