Qingkun, L., S. Yi, et al. (2011). "Lonsdaleite - A material stronger and stiffer than diamond." Scripta Materialia 65(3): 229-232.

Based on first-principles calculations, we demonstrate that lonsdaleite exhibits many excellent static mechanical properties. For instance, the compressive strength, coefficient of stiffness and Young's modulus of lonsdaleite all exceed the corresponding values for diamond. Moreover, the bulk modulus of lonsdaleite is as good as that of diamond, and its tensile strength is similar to that of diamond. Therefore, our results suggest that lonsdaleite is a stronger and stiffer naturally occurring substance than diamond.