Fulgurite Petrified Lightning Fulgurite, also known as “petrified lightning,” is a natural glass formation created by a lightning strike. Fulgurite is the next best thing to hold a lightning bolt in your hand. These specimens are formed when 3000° intense heat from a lightning bolt fuses sand, soil, or rock into a glass-like material. This is how Fulgurite, or commonly known as a lightning fossil, takes shape. Fulgurites have a hollow, tubular shape and range in colour from light to dark brown. Dark Brown, Lightning Strike, Lightning Strikes, Lightning Bolt, Fossil, Soil, The Next, Heat, Chips