igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and heavy specific gravity.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and heavy specific gravity.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the surface of a planet or moon.
Uses & applications
Used extensively in construction as crushed aggregate, railroad ballast, and in the manufacture of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms prominent geological features like the Giant's Causeway.
Field identification & locations
Identify in the field by its dark, dense, fine-grained appearance, often featuring small visible crystals or vesicles from trapped gas bubbles.
