igneous
Basalt River Stone
Basalt
Hardness: 6 (Mohs scale), Color: Dark grey to black, Luster: Waxy to dull (polished in this case), Crystal structure: Aphanitic (fine-grained), Cleavage: None, Specific gravity: 2.8-3.0
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 (Mohs scale), Color: Dark grey to black, Luster: Waxy to dull (polished in this case), Crystal structure: Aphanitic (fine-grained), Cleavage: None, Specific gravity: 2.8-3.0
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at the earth's surface. This specific specimen has been smoothed by water erosion in a river or beach environment.
Uses & applications
Used in construction for aggregate, high-end landscaping, massage therapy (hot stones), and as tumbled decorative stones.
Geological facts
Basalt is the most common volcanic rock on Earth and also makes up most of the ocean floors. It is also found on the Moon and Mars.
Field identification & locations
Identified by its dark color, heavy weight for its size, and lack of visible crystals to the naked eye. Commonly found in volcanic regions or in riverbeds downstream from volcanic sources.
