Iron Formation (IMAGE) University of California - Riverside Caption This image shows a close-up view of a field sample of 2.7 billion-year-old iron formation from Zimbabwe used in the study. The red color is caused by the iron oxide mineral hematite. Credit Lyons lab, UC Riverside 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.