igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, aphanitic (fine-grained) texture, dull luster, and high specific gravity around 2.8 to 3.0.
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, aphanitic (fine-grained) texture, dull luster, and high specific gravity around 2.8 to 3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface, common in volcanic regions.
Uses & applications
Widely used in construction for crushed stone in road bases, concrete aggregate, and dimension stone.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the oceans and also forms major volcanic features on the Moon and Mars.
Field identification & locations
Identify by its dark, fine-grained matrix, often containing small visible crystals of plagioclase or olivine; common globally in volcanic provinces.
