igneous
Basalt
Basalt
Hardness: 6 on the Mohs scale. Color: Dark grey to black, sometimes weathering to brown or green. Luster: Dull or earthy. Structure: Fine-grained (aphanitic), sometimes vesicular or containing small phenocrysts of olivine or pyroxene.
- Hardness
- 6 on the Mohs scale
- Color
- Dark grey to black, sometimes weathering to brown or green
- Luster
- Dull or earthy
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Physical properties
Hardness: 6 on the Mohs scale. Color: Dark grey to black, sometimes weathering to brown or green. Luster: Dull or earthy. Structure: Fine-grained (aphanitic), sometimes vesicular or containing small phenocrysts of olivine or pyroxene.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at or near the surface of Earth. It is the most common volcanic rock and makes up much of the oceanic crust.
Uses & applications
Extensively used in construction as an aggregate for roads, railroad ballast, and concrete. It is also used as dimension stone for tiles and memorials.
Geological facts
Basalt is also prevalent on other celestial bodies, making up the vast majority of the lunar maria on the Moon and much of the surface of Mars and Venus.
Field identification & locations
Identify by its heavy weight, dark color, and fine texture. It is often found in volcanic regions, lava fields, and oceanic ridges. It usually lacks visible large crystals to the naked eye.
