When transparent and free from flaws it is highly valued as a precious stone.
It is also used industrially, especially as an abrasive. Crystallized carbon produced artificially is also called diamond.
The name diamond is derived from the ancient Greek adamas("invincible").
Their hardness and high dispersion of light make diamonds useful for industrial applications and jewelry.
Diamonds make excellent abrasives, because they can be scratched only by other diamonds, or man-made materials, which also means that they hold a polish extremely well and retain their lustre.
They have been treasured as gemstones since their use as religious icons in ancient India. Their usage in engraving tools also dates to early human history.
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 marketing campaigns.
Gem diamonds are commonly judged by the “four Cs”: Carat weight,Clarity, Color, and Cut.
Approximately 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion, and about 100,000 kg of synthetic diamonds are manufactured annually.
49% of natural 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 mined from kimberlite and lamproite volcanic pipes, which brought to the surface the diamond crystals from 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 (aka "blood diamonds") by African paramilitary groups.
CutThe cut of a diamond refers to its proportions. Of the 4C's, the cut is the aspect most directly influenced by man. The other three are dictated by nature.
Quite often the cut of a diamond is confused with its shape. Diamonds are cut into various shapes depending upon the original form of the uncut diamond, which is referred to as “rough.” Whatever the shape, a well-cut diamond is better able to reflect light.