Fulgurite By Matt Young August 10, 2009 12:00 MST Photograph by Virginia Pasek. Photography contest, finalist in the “Minerals” category. Fulgurite – Glass formed as lightning strikes sand or soil. Phosphate-containing sand was fused and turned into phosphite. This otherwise unknown natural phosphite explains the existence of phosphite-eating bacteria. In the center is a small granitic pebble that was trapped during the formation of the glass. A bolt of electricity traveled along its surface, leaving permanent evidence of its passage. Tucson, Arizona, 2007.