Material properties of diamond Material properties of diamond Diamond is the allotrope of carbon in which the carbon atoms are arranged in the specific type of cubic lattice called diamond cubic. Diamond is an optically isotropic crystal that is transparent to opaque. Diamond is the hardest naturally occurring material known. Yet, due to important structural weaknesses, diamond's toughness is only fair to good. The precise tensile strength of diamond is unknown, however strength up to 60 GPa has been observed, and it could be as high as 90–225 GPa depending on the crystal orientation. The anisotropy of diamond hardness is carefully considered during 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