Fulgurite......what the heck is that? That by the way, is an irregular glass rod created by lightning strikes to the earth. While bottle hunting the white sand dunes in Southern Fl along the East Coast for old homesites over a period of about 30 years, I'd occasionally spot these fragments left by a lightning strike into the dune. Varying diameters and depth of penetration into the soil depended on the intensity of the lightning strike. I carefully try to extract as a long a piece as possible without breaking the "rod", but being so delicate they break before I can get a really long piece. The inside of these irregular rods are shinny glass smooth while the outside is the coarseness of sand grains where it was caused by rapid dissipation of the heat and no longer bond the sand grains.