Pressure dependence of the elastic wave velocities for Mg2GeO4 spinel to 3 Gpa

New measurements of compressional and shear wave velocities on polycrystalline Mg2GeO4 spinel (γ) to 3 GPa have yielded the first reported data on pressure derivatives of bulk and shear moduli for this material. The measured values (dK/dP = 4.1 and dG/dP = 1.2) are compared with pressure derivatives for MgAl2O4 spinel. Although dK/dP is comparable for the two materials, dG/dP is much higher for the germanate. Pressure derivatives of elastic properties of mantle spinels cannot be simply predicted from the data on the two analogue materials presently available although single crystal measurements of elastic moduli of magnesium germanate and magnesium silicate spinels at atmospheric pressure by Weidner and co‐workers lend support to the use of magnesium germanate as an elastic analogue for silicate spinels of the Earth's mantle.