igneous
Basalt River Stone
Basalt
Hardness: 6.0; Color: Dark grey to black; Luster: Dull; Crystal Structure: Aphanitic (fine-grained); Specific Gravity: 2.8-3.0
- Hardness
- 6
- Color
- Dark grey to black
- Luster
- Dull
Identified More igneous →
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Physical properties
Hardness: 6.0; Color: Dark grey to black; Luster: Dull; Crystal Structure: Aphanitic (fine-grained); Specific Gravity: 2.8-3.0
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at or very near the surface of Earth. The rounded shape indicates erosion by water in a river or coastal environment.
Uses & applications
Commonly used in landscaping, as drainage stone, in construction aggregates, and for hot stone massage therapy.
Geological facts
Basalt is the most common rock type in the Earth's crust and makes up most of the ocean floor. It is also found on the Moon and Mars.
Field identification & locations
Identified by its dark color, heavy weight (density), and lack of visible crystals. Commonly found in riverbeds and along volcanic coastlines.
