WHAT IS THIS?
A fulgurite is produced, when lightning discharges into ground, making sand grains fuse. In mountain regions, rock fulgurites made of glass also exist.
A thunderstorm discharges lightning into the ground. The most intensive examples of lightning are up to 250 kA, and their temperature can reach 30,000 °C.
Due to the high amperage, billions of watts are deposited in the upper layers of the ground, where lightning strikes.
If lightning strikes in sand, the result is sintering. Sintered sand grains produce a tube – a fulgurite – which exhibits the electricity’s path into the ground.