Diamonds - Carbon Cycle (IMAGE) University of Alberta Caption Diamonds from Kankan, Guinea, analyzed in this study The imperfections inside the diamond are small inclusions of a mineral called ferropericlase, which is from the lower mantle. Credit Anetta Banas Usage Restrictions With credit. 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.