Fulgurite, also known as petrified lightning, is a word derived from the Latin fulgur, meaning thunderbolt. It is a tube of glass that formed in a second or less when lightning struck loose sand or soil and imposed on the starting material a temperature of at least 1800º C. The heat caused the silica or silica-rich material to melt and fuse. Beach sands and dune sands are great hosts for petrified lightning, as are mountain tops, providing on a given mountain top or ridge there are loose cohesionless sands and/or soils to be hit.
I identified this piece as fulgurite when an archaeologist, working on our Mt. Lykaion Survey and Excavation Project at the Sanctuary of Zeus, told me she found it while excavating. She asked if I thought it might be a piece of cinder, e.g., from the lignite mines about 10 km away. I jumped out of my chair and exclaimed “fulgurite!,” having been primed to look for it by the world’s lightning expert, Dr. Phil Krider, University of Arizona. Finding this in an ash altar (bone ash) where abundant dedications to Zeus are being uncovered accelerates the imagination. We can imagine a pilgrim, athlete, or priest, sometime between 2000 and 200 BCE, carrying this to the Sanctuary and ‘giving it back’ to its ‘maker,’ i.e., Zeus. This piece is on loan to me by the Greek Archaeological Service, Tripolis, a partner in the project. Next step is to analyze it in order to interpret source material, with the objective of determining whether or not this fulgurite could have been made on Mt. Lyakaion proper. Alternatively, if the fulgurite’s composition is incompabible with the geologic materials on Mt. Lyakion, we might conclude that the fulgurite had to have been brought to the site from afar by someone who traveled to give homage to Zeus.