A set of fulgurites exhibiting good detail and multiple fused surfaces. 12 grams total, 36-42 mm (1 3/8 - 1 5/8 in.). From Sahara Desert, North Africa. Private Shropshire, UK collection. When lightning strikes dry sand, the intense heat melts and fuses the silica creating tubes of rough glass called fulgurites. The process happens quickly, often trapping molecules from the surrounding atmosphere inside the walls of the impact tube. These natural time capsules allow scientists to study theposition of ancient climates. [6, No Reserve]