High-precision measurements of thermal diffuse x-ray scattering revealed that the full elasticity tensor can accurately be obtained in a single crystal diffraction experiment. The new method opens the perspective to determine elastic properties together with crystal structure under the same experimental conditions. The results published in Physical Review Letters show, that absolute values can be obtained within a model-free analysis with a precision comparable to standard methods. The advantage of the new method is its applicability to very small and opaque crystals of arbitrary shape and symmetry. It implies a broad applicability in material science, geophysics and in the study of sound wave anomalies due to fundamental interactions in condensed matter physics.