Geobacter cell (IMAGE) Michigan State University Caption This Geobacter cell -- which looks a bit like a gray peanut in this microscope image -- is speckled with a dark coating of cobalt minerals that would be toxic to many organisms. Credit Hunter Dulay, MSU 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.