Most often colorless to yellow or brown. Rarely pink, orange, green, graphite heat exchanger pdf, gray, or red. 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. 225 GPa depending on the crystal orientation.
The anisotropy of diamond hardness is carefully considered during diamond cutting. Scientists classify diamonds into four main types according to the nature of crystallographic defects present.
Trace impurities substitutionally replacing carbon atoms in a diamond’s crystal structure, and in some cases structural defects, are responsible for the wide range of colors seen in diamond. Most diamonds are electrical insulators but extremely efficient thermal conductors. 10 on the Mohs scale of mineral hardness.