metamorphic
Fulgurite
Fulgurite (Lechatelierite-rich variety)
Hardness: 6.5 (but fragile); Color: Tan, brownish-gray, with dark interior; Luster: Vitreous/Glassy; Structure: Amorphous tube-like glass; Cleavage: None; Specific Gravity: Approx. 2.2
- Hardness
- 6
- Color
- Tan, brownish-gray, with dark interior
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 6.5 (but fragile); Color: Tan, brownish-gray, with dark interior; Luster: Vitreous/Glassy; Structure: Amorphous tube-like glass; Cleavage: None; Specific Gravity: Approx. 2.2
Formation & geological history
Formed instantaneously when a high-voltage lightning strike hits sand or soil, fusing silicate minerals into glass. Can occur across all geological ages in arid or coastal environments.
Uses & applications
Primarily used for scientific research into lightning physics, fossilized weather, and as a novelty for mineral collectors and jewelry makers.
Geological facts
Commonly known as 'Petrified Lightning.' The temperature of the strike reaches over 1,800°C (3,270°F), creating a rare natural glass called lechatelierite.
Field identification & locations
Identify by its hollow tube structure, rough sand-crusted exterior, and smooth glassy interior. Most common in Saharan deserts, Florida, and other lightning-prone sandy regions.
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