Rock Fulgurite (IMAGE) University of Pennsylvania Caption A rock fulgurite discovered on a rock outcropping in southern France revealed that lightning strikes alter quartz's crystal structure on the atomic level. Credit University of Pennsylvania Usage Restrictions In context of reporting License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.