igneous
Basalt River Stone
Basalt (Aphanitic Mafic Volcanic Rock)
Hardness: 6-7 Mohs; Color: Dark grey to charcoal black; Luster: Dull/Matte; Crystal structure: Aphanitic (fine-grained); Specific gravity: 2.8 - 3.0
- Hardness
- 6-7 Mohs
- Color
- Dark grey to charcoal black
- Luster
- Dull/Matte
Identified More igneous →
Explore Basalt River Stone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 Mohs; Color: Dark grey to charcoal black; Luster: Dull/Matte; 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 Earth's surface. This specific specimen has been smoothed over time by fluvial (river) erosion.
Uses & applications
Used in landscaping, construction (as aggregate), hot stone massage therapy, and as decorative river rock in gardens.
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
Identify by its dark color, heavy weight (density), and lack of visible crystals. Commonly found in riverbeds, volcanic regions, and coastal areas.
