Coal (2 of 2) (IMAGE) Rice University Caption An electron microscope image shows the stacking layer structure of graphene quantum dots extracted from anthracite in a process developed by chemist James Tour at Rice University. The scale bar equals 100 nanometers. Credit Tour Group/Rice University Usage Restrictions None 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.