Fulgurite

Fulgur: Latin for lightning

Lightning flashes at about 100 times per second and nearly one third of that lightning reaches the Earth. When lightning hits rock it creates rock fulgurite, a brownish-green glass. This less common form of fulgurite usually only occurs on mountaintops. The more common sand fulgurite occurs when lightning strikes sand. It makes a hole and around that hole is where the fulgurite forms. The lightning leaves a glass tube following along the branched path of the original strike. For this reason, sand fulgurite can be enormous. The largest piece of sand fulgurite was found in Florida. Its two branches totaled 33 feet!

As a product of lightning sand fulgurite has obvious correspondences with gods such as Zeus or Jupiter, supreme among the Greco-Roman gods, who is often portrayed with a thunderbolt in hand.