igneous
Vesicular Basalt (Scoria)
Basalt with vesicular texture
Hardness: 5-6 (Mohs); Color: Dark grey, black, or reddish-brown; Luster: Dull/Earthy; Structure: Aphanitic (fine-grained) with vesicles (voids); Cleavage: None; Specific Gravity: 2.5-3.0.
- Hardness
- 5-6 (Mohs)
- Color
- Dark grey, black, or reddish-brown
- Luster
- Dull/Earthy
Identified More igneous →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 5-6 (Mohs); Color: Dark grey, black, or reddish-brown; Luster: Dull/Earthy; Structure: Aphanitic (fine-grained) with vesicles (voids); Cleavage: None; Specific Gravity: 2.5-3.0.
Formation & geological history
Formed from extrusive volcanic activity where gas bubbles are trapped in rapidly cooling lava. These specimens can range from thousands to millions of years old, often found in Cenozoic volcanic fields.
Uses & applications
Commonly used in landscaping (lava rock), as a lightweight aggregate in concrete, for heat retention in BBQ grills, and in road construction.
Geological facts
The holes in the rock, called vesicles, are the result of gas escaping from the magma as it reaches the surface and the pressure drops, much like bubbles in a carbonated drink.
Field identification & locations
Identify by its lightweight feel compared to solid rocks and the presence of numerous small pits or holes (vesicles). Commonly found in volcanic regions like Hawaii, Iceland, and the American Southwest.
