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What is a Diamond?
Diamond is the hardest known natural material
(third-hardest known material below aggregated diamond nanorods and
ultrahard fullerite), and is the more costly of
the two best known forms (or allotropes) of carbon, whose hardness and
high dispersion of light make it useful for industrial
applications and jewellery. (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 tons are synthesized annually.
The name “diamond” derives from the ancient
Greek adamas (ad?µa?; “invincible”). The
history of Diamonds shows
that they have been treasured as gemstones for at least 2,500 years. The
popularity of diamonds has risen since the 19th century because of increased
supply, improved cutting and polishing
techniques, growth in the world economy, and innovative and successful
advertising campaigns. They are
commonly judged by the
“four Cs”:
carat,
clarity,
color, and
cut
(shape).
Roughly 49% of diamonds originate from central
and southern Africa, although significant sources of the mineral have been
discovered in Canada, India, Russia, Brazil, and
Australia. They are generally mined from volcanic pipes, which are deep in
the Earth where the high pressure and temperature
enables the formation of the crystals. The mining and distribution of
natural diamonds are subjects of frequent
controversy—such as with concerns over the sale of conflict diamonds
by
African paramilitary groups. There are also allegations
that the De Beers Group misuses its dominance in the industry to
control supply and manipulate price via monopolistic
practices, although in recent years the company's market share has
dropped to below 60%. The world's top diamond cutting
and polishing center is India. It processes 11 out of 12 diamonds
in jewelery worldwide. The sector employs 1.3 million
people and accounts for 14% of India's $80 billion of annual exports.
Its share in the world polished diamond market
is 92% by pieces and 55% by value.
Definition information from Wikipedia: the free
encyclopedia
http://en.wikipedia.org/wiki/Diamond
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