igneous
Vesicular Basalt
Aphanitic Mafic Volcanic Rock
Hardness: 6.0; Color: Dark grey to reddish-brown due to iron oxidation; Luster: Dull to earthy; Structure: Vesicular (contains small cavities or voids); Cleavage: None
- Hardness
- 6
- Color
- Dark grey to reddish-brown due to iron oxidation
- Luster
- Dull to earthy
Identified More igneous →
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Physical properties
Hardness: 6.0; Color: Dark grey to reddish-brown due to iron oxidation; Luster: Dull to earthy; Structure: Vesicular (contains small cavities or voids); Cleavage: None
Formation & geological history
Formed from the rapid cooling of lava rich in gas. As the gas bubbles were trapped during solidification, they created the holes (vesicles). Often associated with volcanic eruptions in the Cenozoic era.
Uses & applications
Commonly used in landscaping as decorative 'lava rock,' in construction for road base and concrete aggregate, and occasionally in industrial grinding stones.
Geological facts
The holes in vesicular basalt are called vesicles. When these holes are later filled with minerals like quartz or calcite, the rock is then called amygdaloidal basalt.
Field identification & locations
Identified by its distinctive porous, 'Swiss cheese' appearance and heavy weight relative to its size (when not overly porous). Frequently found in volcanic fields, ocean ridges, and basaltic plateaus.
