igneous
Basalt
Basalt (Mafic volcanic rock)
Hardness: 6.0; Color: dark grey to black; Luster: dull to earthy; Structure: fine-grained (aphanitic) or vesicular; Specific gravity: 2.8-3.0.
- Hardness
- 6
- Color
- dark grey to black
- Luster
- dull to earthy
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Physical properties
Hardness: 6.0; Color: dark grey to black; Luster: dull to earthy; Structure: fine-grained (aphanitic) or vesicular; Specific gravity: 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava exposed at or very near the surface of a terrestrial planet or a moon.
Uses & applications
Extensively used in construction as aggregate for roads and concrete, railway ballast, and occasionally for statues or high-end architectural tiles.
Geological facts
Basalt is the most common rock type in Earth's crust, making up most of the ocean floors. It is also common on the Moon and Mars.
Field identification & locations
Identify by its dark color, heavy weight (density), and fine-grained texture. Found near volcanic sites and oceanic crust exposures.
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