An homogeneous upper mantle chemical composition defined by the pyrolite model is compatible with the observed seismic velocities. Such a test is now possible for depths to 670 km as a result of new mineral elasticity and phase equilibria data. Three specific criteria for comparing the mineralogical velocity model with that of the mantle include i) the velocity jump at the 400 km discontinuity, ii) the velocity increase between 400 and 670 km, and iii) the absolute value of velocity in the 300 to 400 km region (shallower than the discontinuity). The first criterion is sensitive to the olivine content of the mantle and the pressure derivatives of the elastic properties of the high pressure phase. The application of this criterion suggests a mantle with 40--65% olivine by volume. The second criterion is sensitive to the details of the pyroxene to garnet transformation and the relative abundances of the pyroxenes and garnet. The third criterion depends on details of this transformation as well as iron content an the temperature of the mantle.