Volcanic & Metamorphic
Fused Glass
What it is
Fulgurite — natural glass tubes formed when lightning strikes sand or soil. The extreme heat (30,000°C, hotter than the sun's surface) instantly fuses silica grains into hollow glass tubes that record the lightning bolt's path underground.
How it forms
Created instantaneously when lightning contacts silica-rich sand or soil. The bolt travels downward, melting everything in its path and leaving behind a fragile glass tube.
Fused SiO₂ (lechatelierite)
