igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, aphanitic (fine-grained) texture, and dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, aphanitic (fine-grained) texture, and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at the Earth's surface.
Uses & applications
Commonly used in construction, road aggregate, railroad ballast, and sometimes for stone countertops.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and forms massive geological formations like the Giant's Causeway.
Field identification & locations
Identify in the field by its dark, fine-grained appearance and heavy weight relative to its size, often found in volcanic regions worldwide.
