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Diamonds make excellent abrasives because they can be scratched only by other
diamonds, extremely well and retain luster. About 130 million carats (26,000 kg)
are mined annually, with a total value Borazon, ultra-hard fullerite, or aggregated
diamond nanorods, which also means they hold a polish of nearly USD $9 billion.
About 100,000 kg are synthesized annually 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.
The name “diamond” derives from the ancient Greek adamas (αδάμας; "invincible”).
They have been treasured as gemstones since their use as religious icons in India at
least 2,500 years ago—and usage in drill bits and engraving tools also dates to early
human history. 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. Although synthetic
diamonds are produced each year at nearly four times the rate of natural diamonds,
the vast majority of synthetic diamonds produced are small imperfect diamonds
suitable only for industrial-grade use.
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%.
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