igneous
Vesticular Basalt
Vesicular Basalt
Hardness: 5-6 (Mohs); Color: Dark gray to black; Luster: Dull/Earthy; Crystal structure: Aphanitic (fine-grained) matrix with vesicles (gas bubbles); Specific Gravity: 2.8-3.0
- Hardness
- 5-6 (Mohs)
- Color
- Dark gray to black
- Luster
- Dull/Earthy
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Physical properties
Hardness: 5-6 (Mohs); Color: Dark gray to black; Luster: Dull/Earthy; Crystal structure: Aphanitic (fine-grained) matrix with vesicles (gas bubbles); 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 holes (vesicles) are created by gas bubbles that were trapped as the lava solidified. Found in volcanic regions worldwide.
Uses & applications
Used primarily in construction as aggregate for concrete and asphalt, landscaping, and sometimes for 'lava rocks' in gas grills or as decorative items.
Geological facts
Basalt is the most common rock in Earth's crust and makes up most of the ocean floor. Large-scale basaltic lava flows can form giant 'traps' like the Deccan Traps in India.
Field identification & locations
Identify by its dark color, heavy weight (relative to pumice), and the presence of small spherical or oval pits. Commonly found in volcanic fields, ocean islands (like Hawaii), and mid-ocean ridges.
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Dark Igneous Rock (Likely Basalt or Diabase)
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