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
Anisodesmic crystal anion equals the charge on that anion." When there is more than one type of bonding in a crystal, strongly anisotropic physical properties can result such as those of graphite. Many other substances have anisotropic physical properties. Such properties are directly related to the atomic structures of the substances. Conversely, halite is an example of an isotropic crystal with equal hardness in all directions. Anisodesmic crystal An anisodesmic crystal (sometimes anisodemic crystal) is a crystal containing bonds with differing electrostatic valencies. All other crystals are known as isodesmic crystals (or isodemic) and examples include diamond and halite. These terms are