fulgurite

n. tubular formation in rock or sand or rock which is caused by lightning

Fulgurites (from the Latin fulgur meaning thunderbolt) are natural hollow carrot-shaped glass tubes formed in quartzose sand or soil by lightning strikes. In the right kind of sand the extreme heat generated will form silica glass shapes that trace the path of the lightning. These structures are also sometimes referred to as petrified lightning. The glass formed is called lechatelierite which may also be formed by meteorite impact and volcanic explosions. As it is amorphous it is classified as a mineraloid.
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n. fulgurite

(n.)
A vitrified sand tube produced by the striking of lightning on sand; a lightning tube; also, the portion of rock surface fused by a lightning discharge.
  

fulgurite /'fʌlgərait/
danh từ (địa lý,ddịa chất) Fungurit (đá bị sét đánh hoá thành thuỷ tinh) Fungurit (một loại chất nổ)
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