Igneous
Basalt
Basalt
Hardness: 5.5-6 on Mohs scale. Color: Dark gray to black. Luster: Dull to earthy. Texture: Fine-grained (aphanitic), sometimes vesicular or porphyritic.
- Hardness
- 5
- Color
- Dark gray to black
- Luster
- Dull to earthy
Identified More igneous →
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Physical properties
Hardness: 5.5-6 on Mohs scale. Color: Dark gray to black. Luster: Dull to earthy. Texture: Fine-grained (aphanitic), sometimes vesicular or porphyritic.
Formation & geological history
Formed by the rapid cooling of basaltic lava at or near the surface of a planet or moon. Geologically common.
Uses & applications
Used in construction (crushed rock for road base, concrete aggregate), dimensional stone, and occasionally in producing stonewool for thermal insulation.
Geological facts
Basalt is the most common volcanic rock on Earth and also makes up a significant portion of the oceanic crust.
Field identification & locations
Identified by its dark color, fine grain, and relative heaviness. Often found smoothed out as river rocks or beach pebbles, like the one shown.
