Fulgurites

The WebEcoist has a nice article on fulgurites which are a type of natural glass formed when lightning strikes silica-rich soil. From the article…

The word fulgurite is derived from “fulgur”, which means “thunderbolt” in Latin. That’s just part of the story, though, as the real action begins once the bolt hits the ground. The average lightning bolt packs up to a gigajoule of energy – enough to power an all-electric home for about a week, or around 300 kilowatt-hours. When a strike enters the ground it makes its presence known by vaporizing soil & sand along a downward, branching path that may be up to 20 feet long. Temperatures of up to 50,000 degrees blast sand (silicon dioxide) into a hollow tube lined with what is essentially glass: a fulgurite.

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