mineral
Fulgurite
Lechatelierite (Silica glass tubes)
Hardness: 5.5 to 6 on the Mohs scale; Color: Dark brown, black, grey, or tan; Luster: Vitreous to dull; Crystal structure: Amorphous (silica glass); Cleavage: None (conchoidal fracture); Specific gravity: ~2.2
- Hardness
- 5
- Color
- Dark brown, black, grey, or tan
- Luster
- Vitreous to dull
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Physical properties
Hardness: 5.5 to 6 on the Mohs scale; Color: Dark brown, black, grey, or tan; Luster: Vitreous to dull; Crystal structure: Amorphous (silica glass); Cleavage: None (conchoidal fracture); Specific gravity: ~2.2
Formation & geological history
Formed when a high-voltage lightning strike (typically 30,000+ amps) discharges into sandy soil or rock, instantly melting and fusing the grains together at temperatures exceeding 1,800 degrees Celsius.
Uses & applications
Prized by mineral collectors, educational displays, and sometimes used in jewelry or as a unique conversational piece.
Geological facts
Fulgurites are often called 'fossilized lightning' and are the physical record of an ancient or recent atmospheric electrical discharge into the ground.
Field identification & locations
Found in sandy deserts, beaches, or high-altitude mountain peaks where lightning strikes are frequent. Identified by its tubular, glassy, and fused-sand structure.
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