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
Synthetic diamond a superconductor), allowing it to be used in electronic applications. Nitrogen impurities hinder movement of lattice dislocations (defects within the crystal structure) and put the lattice under compressive stress, thereby increasing hardness and toughness. Unlike most electrical insulators, pure diamond is a good conductor of heat because of the strong covalent bonding within the crystal. The thermal conductivity of pure diamond is the highest of any known solid. Single crystals of synthetic diamond enriched in (99.9%), isotopically pure diamond, have the highest thermal conductivity of any material, 30 W/cm·K at room temperature, 7.5 times higher than copper. Natural diamond's conductivity