Fulgurites (from the Latin word fulgur, meaning “lightning”) are petrified lightning, created when lightning strikes an area of dry sand. The intense heat of the lightning melts the sand surrounding the stroke into a rough, glassy tube forming a fused record of its path. These tubes may be 0.5 to 2 inches (1.5 to 5 centimeters) in diameter, and up to 10 feet (3 meters) in length. They are extremely brittle and break easily. The inside walls of the tube are glassy and lustrous while the outside is rough, with sand particles adhering to it. Fulgurites are usually tan or black in color, but translucent white ones also have been found.