igneous
Basalt River Stone
Basalt (Mafic volcanic rock)
Hardness: 6.0 on Mohs scale. Color: Dark gray to black. Luster: Dull or earthy. Crystal Structure: Aphanitic (fine-grained due to rapid cooling). Specific Gravity: 2.8 - 3.0.
- Hardness
- 6
- Color
- Dark gray to black
- Luster
- Dull or earthy
Identified More igneous →
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Physical properties
Hardness: 6.0 on Mohs scale. Color: Dark gray to black. Luster: Dull or earthy. Crystal Structure: Aphanitic (fine-grained due to rapid cooling). Specific Gravity: 2.8 - 3.0.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava. This specimen has been rounded by mechanical erosion in a river or high-energy beach environment.
Uses & applications
Used primarily in construction (crushed stone, asphalt aggregate), aquarium decor, massage stones, and general landscaping.
Geological facts
Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floor. It is similar in composition to the lunar maria on the Moon.
Field identification & locations
Identify by its dark color, heavy weight (relative to size), and very fine-grained texture. Commonly found in volcanic regions and riverbeds carrying volcanic runoff.
