MgAl2O4:Cr3+ and emerald display a different colour but the local symmetry is the same: Microscopic origin

J. M. Garcia-Lastra, M. T. Barriuso, J. A. Aramburu +1

The difference in colour between emerald (Be3Si6Al2O18:Cr3+, green) and the Cr3+-doped spinel MgAl2O4 (red) is striking, considering that in both systems colour is due to CrO69- co…