Lapis in Calculus (IMAGE) Max Planck Institute of Geoanthropology Caption This is a magnified view of lapis lazuli particles embedded within medieval dental calculus. Credit Monica Tromp Usage Restrictions This image may only be used in the context of reporting on this publication and with appropriate credit information. 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.