igneous
Vesicular Basalt (or Scoria)
Vesicular Basalt
Hardness: 5-6 Mohs; Color: Grey, black, or reddish-brown; Luster: Dull/Earthy; Structure: Aphanitic (fine-grained) with vesicles; Specific Gravity: 2.4 - 3.1
- Hardness
- 5-6 Mohs
- Color
- Grey, black, or reddish-brown
- Luster
- Dull/Earthy
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Physical properties
Hardness: 5-6 Mohs; Color: Grey, black, or reddish-brown; Luster: Dull/Earthy; Structure: Aphanitic (fine-grained) with vesicles; Specific Gravity: 2.4 - 3.1
Formation & geological history
Formed through 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 (rock wool), road base construction, and as abrasive polishing stones (pumice-like variants).
Geological facts
The word 'basalt' is derived from Late Latin 'basaltes', a misspelling of 'basanites' meaning 'very hard stone'. This rock is common on the Moon and Mars.
Field identification & locations
Identify by its light weight relative to its size and the presence of numerous small pits or holes. Commonly found in volcanic fields, oceanic islands (like Hawaii), and mid-ocean ridges.
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