This suggests that the additional d

This suggests that the additional deformation visible in Fig. 3e for the specimen pressed at 800 MPa is mostly elastic and thus reversible. As observed for the experiments in different media (Fig. 2c,d and Supplementary Fig. 3a,b), the relative density of the powder compact was found to exhibit a logarithmic dependence on the applied stress (Supplementary Fig. 7), which qualitatively agrees with the behaviour expected for geological and synthetic materials.