Elasticity of Selected Rocks and Minerals

been the subject of numerous investigations (Birch, 1960, 1961). In this study, measurement of bulk density and of compressional and rotational wave velocities of a variety of rocks and minerals affords the opportunity of calculating elastic constants and of studying anisotropy in elastic velocities. Although it was not possible to take into account the effect of confining pressure on velocities, atmospheric-pressure values of velocities and elastic constants display considerable order in their density-dependence. This order could be increased and somewhat modified by measurement at pressures sufficiently high to reduce the effects of porosity, microfractures, and other structural defects, and by taking into account the atomic packing density, as measured by density and mean atomic weight (Birch, 1961).