igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness: 6 on the Mohs scale. Color: Dark gray to black. Luster: Dull to sub-mat. Crystal structure: Aphanitic, fine-grained.
- Hardness
- 6 on the Mohs scale
- Color
- Dark gray to black
- Luster
- Dull to sub-mat
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Physical properties
Hardness: 6 on the Mohs scale. Color: Dark gray to black. Luster: Dull to sub-mat. Crystal structure: Aphanitic, fine-grained.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in magnesium and iron exposed at or very near the surface of a planet or moon.
Uses & applications
Used extensively in construction as crushed aggregate for roads, railroad ballast, and in the production of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also makes up most of the volcanic islands on Earth.
Field identification & locations
Identify by its dark, fine-grained matrix and heavy feel; commonly found in volcanic regions worldwide.
