igneous
Vesicular Basalt
Basalt with secondary mineral infills
Hardness: 5-6 (Mohs scale); Color: Dark grey to charcoal; Luster: Dull/Earthy; Structure: Vesicular (pitted with holes from gas bubbles); Fine-grained aphanitic texture.
- Hardness
- 5-6 (Mohs scale)
- Color
- Dark grey to charcoal
- Luster
- Dull/Earthy
Identified More igneous →
Explore Vesicular Basalt in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5-6 (Mohs scale); Color: Dark grey to charcoal; Luster: Dull/Earthy; Structure: Vesicular (pitted with holes from gas bubbles); Fine-grained aphanitic texture.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava at or very near the Earth's surface. The holes (vesicles) were formed by gas bubbles escaping as the lava solidified.
Uses & applications
Used widely in construction as aggregate, road base, and concrete. Small river-worn specimens are popular in aquarium decor or as 'worry stones'.
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 in the field by its dark color, heavy weight (high specific gravity), and characteristic small holes. This specimen appears to be water-worn, suggesting it was found in a river or coastal environment.
