Diamond cubic strong isotropic property. Namely, for any two vertices "x" and "y" of the crystal net, and for any ordering of the edges adjacent to "x" and any ordering of the edges adjacent to "y", there is a net-preserving congruence taking "x" to "y" and each "x"-edge to the similarly ordered "y"-edge. Another (hypothetical) crystal with this property is the Laves graph (also called the K crystal, (10,3)-a, or the diamond twin). The compressive strength and hardness of diamond and various other materials, such as boron nitride, is attributed to the diamond cubic structure. Similarly truss systems that follow the diamond
Wurtzite crystal structure are the same as in lonsdaleite (hexagonal diamond). Each atom is tetrahedrally coordinated. The wurtzite structure is non-centrosymmetric (i.e., lacks inversion symmetry). Due to this, wurtzite crystals can (and generally do) have properties such as piezoelectricity and pyroelectricity, which centrosymmetric crystals lack. Wurtzite crystal structure The wurtzite crystal structure, named after the mineral wurtzite, is a crystal structure for various binary compounds. It is an example of a hexagonal crystal system. The chemical prototype is conventionally given as ZnS, although mineral wurtzite is a multi-component alloy compound. The wurtzite crystal structure is referred to by the B4 and the Pearson