"This is What Happens When Sand Gets Struck by Lightning: Fulgurites are natural hollow glass tubes formed in quartzose sand, silica, or soil by lightning strikes (at 3,270 °F), which instantaneously melts silica on a conductive surface and fuses grains together over a period of around one second. Photographed by Ken Smith."
Fulgurite = Latin word ‘fulgur’ which means thunderbolt. Fulgurite is created when lightning strikes sand. The high temperature of lightning, air-temperatures over 30,000 °C have been measured, is far higher than the sand melting point of 1800 °C. The silica that sand is made up of fuses together, creating the so-called lightning glass or lightning sand.