igneous
Vesicular Basalt (Scoria)
Vesicular Basalt
Hardness: 5-6 (Mohs); Color: Dark brown to black; Luster: Dull to earthy; Structure: Aphanitic (fine-grained) with vesicles (gas bubbles); Specific Gravity: 2.5-3.0.
- Hardness
- 5-6 (Mohs)
- Color
- Dark brown to black
- Luster
- Dull to earthy
Identified More igneous →
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Physical properties
Hardness: 5-6 (Mohs); Color: Dark brown to black; Luster: Dull to earthy; Structure: Aphanitic (fine-grained) with vesicles (gas bubbles); Specific Gravity: 2.5-3.0.
Formation & geological history
Formed from the rapid cooling of magnesium-rich and iron-rich lava. The holes (vesicles) are created by gas bubbles trapped in the lava as it solidifies at the surface.
Uses & applications
Used in landscaping, high-temperature insulation, drainage rock, and as an abrasive in stone-washing processes.
Geological facts
Scoria is similar to pumice but is denser and has larger vesicles with thicker walls. Because of its iron content, it is much heavier and usually darker than pumice.
Field identification & locations
Identify by its 'sponge-like' or 'swiss cheese' appearance and dark color. It is commonly found in volcanic fields such as those in Iceland, Hawaii, and Arizona.
