igneous
Basalt Pebble
Aphanitic mafic igneous rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark grey to black color, dull to sub-withering luster, fine-grained aphanitic crystal structure.
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Physical properties
Hardness of 6 on Mohs scale, dark grey to black color, dull to sub-withering luster, fine-grained aphanitic crystal structure.
Formation & geological history
Formed from the rapid cooling of low-viscosity, iron- and magnesium-rich lava flows at the Earth's surface.
Uses & applications
Used widely in construction as crushed stone, railroad ballast, and aggregate, as well as in manufacturing stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's oceans and forming major volcanic features.
Field identification & locations
Easily identified by its dark, dense, fine-grained appearance, often found along riverbeds, beaches, and volcanic regions.
