Breaking Boundaries (IMAGE) Rensselaer Polytechnic Institute Caption The boundaries between grains of rock could be a pathway for metals to move between Earth's core and mantle. Credit Leslie Hayden/Rensselaer Polytechnic Institute Usage Restrictions Please credit photo 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.