Feldspar (IMAGE) Florida State University Caption Assistant Professor Mainak Mookherjee found that the mineral feldspar became softer under extreme pressure. Credit Mainak Mookherjee 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.