mineraloid
Fulgurite
Lechatelierite (Silica glass), typically SiO2
Hardness: 5.5-7 Mohs; Color: Gray, tan, or white with a glassy interior; Luster: Vitreous to dull; Structure: Amorphous silica glass; Cleavage: None; Specific Gravity: 2.1-2.2
- Hardness
- 5
- Color
- Gray, tan, or white with a glassy interior
- Luster
- Vitreous to dull
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Physical properties
Hardness: 5.5-7 Mohs; Color: Gray, tan, or white with a glassy interior; Luster: Vitreous to dull; Structure: Amorphous silica glass; Cleavage: None; Specific Gravity: 2.1-2.2
Formation & geological history
Formed when lightning strikes sand, soil, or rock, instantly melting and fusing silicon dioxide into a hollow glass tube. Found in deserts or beaches following high-energy electrical storms.
Uses & applications
Primary use in geological research, as a collector specimen, and occasionally in metaphysical jewelry. They are rarely used in industrial applications due to their fragility.
Geological facts
Also known as 'Petrified Lightning.' The temperature reached during formation can exceed 1,800°C (3,270°F), which is hotter than the surface of the sun and sufficient to evaporate silicon.
Field identification & locations
Identify in the field by their rough, branch-like or tubular shape and sandy exterior; they are usually hollow inside. Common in the Sahara Desert, Florida beaches, and the Gobi Desert.
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Fulgurite
Fulgurite (Lechatelierite)
metamorphic