Pyrite image (IMAGE) Penn State Caption Scanning electron microscope images of raspberry-shaped pyrite (left) and partially oxidized pyrite (right), as indicated by the red color, found at the Susquehanna Shale Hills Critical Zone Observatory. Fractures and erosion at the Earth's surface control the rate of pyrite oxidation deep underground, leaving behind iron oxide "fossils" that retain pyrite's shape. Credit Xin Gu, Penn State Usage Restrictions Non commercial use only 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.