Forsterite (image) Carnegie Institution Share Print E-Mail Caption The magnesium silicate forsterite was one of the most abundant minerals in the Hadean Eon, and it played a major role in Earth's near-surface processes. The green color of this mineral (which is also known as the semi-precious gemstone peridot, the birthstone of August) is caused by small amounts iron. The iron can react with seawater to promote chemical reactions that may have played a role in life's origins. Credit Robert Downs, University of Arizona, Ruff Project Usage Restrictions With credit Share Print E-Mail 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.