|
Diamond is an allotrope of
carbon. It is the hardest known natural material
and the third-hardest known material after
aggregated diamond nanorods and ultrahard
fullerite. Its hardness and high dispersion of
light make it useful for industrial applications
and jewelry.
Diamonds are specifically renowned as a material
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 their lustre. Approximately 130 million
carats (26,000 kg) |
 |
|
|
are
mined annually, with a total value of nearly USD $9 billion, and about
100,000 kg are synthesized annually.
The
most familiar usage of diamonds today is as gemstones
used for adornment a usage which dates back into
antiquity. The dispersion of white light into spectral
colors, is the primary gemological characteristic of gem
diamonds. In the twentieth century, experts in the field
of gemology have developed methods of grading diamonds
and other gemstones based on the characteristics most
important to their value as a gem. Four characteristics,
known informally as the four Cs, are now commonly used
as the basic descriptors of diamonds: these are carat,
cut, color, and clarity. |
