igneous
Basalt
Basalt (Mafic volcanic rock)
Hardness: 6 on Mohs scale. Color: Dark grey to black. Luster: Dull to sub-metallic. Crystal Structure: Aphanitic (fine-grained). Specific Gravity: 2.9 to 3.1.
- Hardness
- 6 on Mohs scale
- Color
- Dark grey to black
- Luster
- Dull to sub-metallic
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Physical properties
Hardness: 6 on Mohs scale. Color: Dark grey to black. Luster: Dull to sub-metallic. Crystal Structure: Aphanitic (fine-grained). Specific Gravity: 2.9 to 3.1.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at or near the surface of a planet or moon. Most basalt flows on Earth were formed throughout various Cenozoic eras.
Uses & applications
Extensively used in construction for aggregate, road base, railroad ballast, and dimension stone for paving. Also used as a raw material for cast basalt and high-performance fibers.
Geological facts
Basalt is the most common rock type in the Earth's crust, covering most of the ocean floor. It is גם common on other planetary bodies like the Moon and Mars.
Field identification & locations
Identify by its dark color, heavy weight (density), and fine-grained texture. Often found in volcanic regions, oceanic crust boundaries, and flood basalt provinces like the Deccan Traps or Columbia River Plateau.
