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
Natural History (Pliny) vases and other decorative objects. The account of magnetism includes the myth of Magnes the shepherd. Pliny moves into crystallography and mineralogy, describing the octahedral shape of the diamond and recording that diamond dust is used by gem engravers to cut and polish other gems, owing to its great hardness. He states that rock crystal is valuable for its transparency and hardness, and can be carved into vessels and implements. He relates the story of a woman who owned a ladle made of the mineral, paying the sum of 150,000 sesterces for the item. Nero deliberately broke two crystal cups