The single‐crystal elastic moduli of stishovite

The single‐crystal elastic moduli of stishovite have been determined experimentally from measured Brillouin scattering spectra. They are C 11 = 4.53 ± 0.04, C 33 = 7.76 ± 0.05; C 44 = 2.52 ± 0.02, C 66 = 3.02 ± 0.03; and C 12 = 2.11 ± 0.05, C 13 = 2.03 ± 0.04 in units of mbar. The estimated aggregate (Voigt‐Reuss‐Hill) adiabatic moduli are K = 3.16 ± 0.04 and μ = 2.20 ± .03 mbar. Previous values of the isothermal bulk modulus, obtained from hydrostatic compression experiments, are in agreement with the Reuss value of K T = 3.06 ± .04 mbar (as corrected to isothermal conditions). Taken together, these results suggest that the pressure derivative of the bulk modulus for stishovite is low relative to other rutile structure oxides.