igneous
Basalt Pebble with Vesicles
Vesicular Basalt
Hardness: 6 (Mohs scale); Color: Dark grey to black; Luster: Dull/earthy; Crystal structure: Aphanitic (fine-grained); Features: Small holes (vesicles); Specific gravity: 2.8-3.0.
- Hardness
- 6 (Mohs scale)
- Color
- Dark grey to black
- Luster
- Dull/earthy
Identified More igneous →
Explore Basalt Pebble with Vesicles 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: Dull/earthy; Crystal structure: Aphanitic (fine-grained); Features: Small holes (vesicles); 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. The holes are caused by gas bubbles being trapped as the lava solidified. Likely weathered and rounded by water action in a river or coastal environment.
Uses & applications
Used in construction, as road base, and in landscaping. Highly porous varieties (scoria) are used as garden mulch or for drainage.
Geological facts
Basalt is the most common volcanic rock on Earth and also makes up most of the ocean floor. The dark color is due to the presence of pyroxene and olivine minerals.
Field identification & locations
Look for a dark, heavy, fine-grained rock with small surface pits. It is commonly found in volcanic fields, ancient lava flows, or as smooth pebbles in riverbeds and beaches.
