The stability of (Mg,Fe)SiO3-perovskite at

lower mantle conditions has been the subject of three recent studies (1, 2, 3). While our work (2) and the study of Meade et al. (3) show that perovskite may not be stable in the lower mantle and dissociates into its compo-nent oxides, G. Serghiou et al. (1) come to the opposite conclusion. In that report (1), pe-rovskite was synthesized from a mixture of oxides, and attempts were made to decom-pose a glass of MgSiO3 composition between pressures of 73 to 100 GPa and at tempera-tures to 3000 K. Their experiments (1) were performed in CO2-laser heated diamond anvil cells (DACs) in Ar or CsCl pressure medi-ums, and processes in the samples were char