igneous
Basalt Pebble
Basalt
Hardness: 6.0; Color: Dark grey to black; Luster: Dull to earthy (when unpolished); Structure: Aphanitic (fine-grained), often vesicular; Specific Gravity: 2.8-3.0
- Hardness
- 6
- Color
- Dark grey to black
- Luster
- Dull to earthy (when unpolished)
Identified More igneous →
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Physical properties
Hardness: 6.0; Color: Dark grey to black; Luster: Dull to earthy (when unpolished); Structure: Aphanitic (fine-grained), often 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
Used primarily as aggregate in construction, road base, and concrete; also used for river rock landscaping and hot stone massage therapy.
Geological facts
Basalt is the most common rock type in Earth's crust and makes up most of the ocean floor. It is also extremely common on the Moon and Mars.
Field identification & locations
Identify by its dark color, heavy weight (relative to size), and fine-grained texture. Commonly found on beaches, riverbeds, and near volcanic regions worldwide.
