igneous
Basalt Pebble
Extrusive mafic igneous rock
Hardness: 6-7 (Mohs scale); Color: Dark gray to black, often weathered to brown; Luster: Dull/earthy in weathered state; Crystal structure: Aphanitic (fine-grained); Specific gravity: 2.8-3.0
- Hardness
- 6-7 (Mohs scale)
- Color
- Dark gray to black, often weathered to brown
- Luster
- Dull/earthy in weathered state
Identified More igneous →
Explore Basalt Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6-7 (Mohs scale); Color: Dark gray to black, often weathered to brown; Luster: Dull/earthy in weathered state; 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 exposed at or very near the surface of a terrestrial planet or moon. This specific item appears to be water-worn into a pebble shape.
Uses & applications
Crushed stone for construction, road base, railroad ballast, and occasionally used in stone massage or as decorative garden pebbles.
Geological facts
Basalt is the most common rock type in Earth's crust and covers most of the ocean floor. It is also found on the Moon and Mars.
Field identification & locations
Identify by its dark color, heavy weight for its size, and absence of visible large crystals. Commonly found in volcanic regions, riverbeds, and beaches near basaltic flows.
