One of the fulgurite stubs

Fulgurites have been described as solidified lightning bolts. The examples shown below came from desert sand areas of the southwest. Two of the examples have been tipped on end to show the glassy tube that is formed on the inside as a result of lightning striking the sand and melting the sand granules. Further out from the tube the sand particles are fused together forming a rough textured surface.

Different fulgurite examples

 

The world's record for fulgurites probably goes to this laterally branching example from northern Florida. One branch was 17 feet long and the other opposing branch was 16 feet. The fulgurite was exposed during a week-long excavation in the summer of 1996. The excavation was a long and delicate operation because these glass tubes are so fragile.

Besides the inherent beauty in these delicate structures, fulgurites are studied in an attempt to protect underground power lines. A lightning strike may not destroy the line, but only damage insulation which may then produce a failure many months later.