igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, dull luster, fine-grained aphanitic texture, high specific gravity.
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Physical properties
Hardness 6 on Mohs scale, dark gray to black color, dull luster, fine-grained aphanitic texture, high specific gravity.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed aggregate for roads, railroad ballast, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust, underlying most ocean basins and forming major volcanic features like the Giant's Causeway.
Field identification & locations
Identify by its dark, fine-grained appearance and heavy weight; commonly found in volcanic regions worldwide.
