igneous
Vesicular Basalt
Extrusive mafic igneous rock
Hardness: 5-6 (Mohs); Color: Dark grey to black; Luster: Dull or earthy; Structure: Aphanitic with vesicles; Cleavage: None; Specific Gravity: 2.8–3.0
- Hardness
- 5-6 (Mohs)
- Color
- Dark grey to black
- Luster
- Dull or 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); Color: Dark grey to black; Luster: Dull or earthy; Structure: Aphanitic with vesicles; 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. The 'vesicles' (holes) are caused by gas bubbles trapped in the cooling lava. Found in volcanic regions worldwide.
Uses & applications
Used primarily in construction for road base, concrete aggregate, and railroad ballast. Highly vesicular specimens are used in landscaping and as 'lava rocks' for grills.
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 (relative to size), and characteristic holes or pits on the surface. Commonly found in old volcanic flows and near mountain ranges.
