Karen holding soil (IMAGE) American Society of Agronomy Caption Karen Vaughan holds a piece of soil that shows the greenish-blue, dark colors associated with the parent material. Credit Karen Vaughan Usage Restrictions For use with this story 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.