Bluenile Canada

Diamond is the hardest known natural material and one of the two best known forms (or allotropes) of carbon, whose hardness and high dispersion of light make it useful for industrial applications and jewelry. (The other equally well known allotrope is graphite.)

Diamonds are specifically renowned as a mineral with superlative physical qualities — they make excellent abrasives because they can be scratched only by other diamonds, Borazon, ultrahard fullerite, or aggregated diamond nanorods, which also means they hold a polish extremely well and retain luster. About 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion. About 100,000 kg are synthesized annually. (more…)

Diamonds typically crystallize in the face-centered cubic crystal system (space group ) and consist of tetrahedrally bonded carbon atoms. The unit cell of diamond has a two atom basis at (0,0,0) and (1/4,1/4,1/4), which means half of the atoms are at lattice points and the other half are offset by (1/4,1/4,1/4), where 1 is the length of a side of the unit cell. Diamond’s density is 3.52 g·cm−3.

The tetrahedral arrangement of atoms is the source of many of diamond’s properties. The carbon atoms in Graphite, the other major allotrope of carbon, display a different (nontetrahedral) connectivity and as a result shows dramatically different physical characteristics: graphite is a soft, dark gray, opaque mineral. Other elements of the carbon group such as silicon crystalize like diamond. (more…)