About 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9Billion. About 100,000 kg are synthesized annually.
The name "Diamond" derives from the ancient greek word adamas (invincible)
Diamonds are pure carbon crystals and are the hardest substance know to man. The main colour is white although they occur in a variety of fancy colours, thus enablimg the jeweller to produce fascinating and exciting designs. They are the most common of the four main precious stones, the other three being ruby, emerald and sapphire.
Traditionally, diamond is the emblem of love and fearlessness. The finest are graded as "finest white" and any diamond that is not white, or is of an off-shade of white is referred to as "coloured" or "fancy", with the appropriate colour. Blue-white is a term used to denote a diamond with distinct bluish tinge due to natural flouorescence. Another expression often used is "of the first water" this is not a gemmological term and means nothing
Diamonds have a natural brilliance which is captivated man over the centuries, and the stone has been sought after from early time.
The earliest mining of diamonds was in India, and historically is thought to have dated from around 500B.C. The most important mining area was Golconda. Borneo and indonesia have also produced stones since the dark ages, and these three place were the main sources of the worlds supply until the discovery of diamonds in Brazil in the early 18th century. The impetus that this gave to the diamond trade meant that large quantities of jewellery were produced in Europe in the 18th and 19th century and, far more important, the discoveries in South Africa around the turn of the century, that diamonds began to fall in the price range of ordinary people. Since then, diamonds have been found in large quantities in Africa, Zaire, Sierra Leone - and more recently in Russia. Only a minority of all stone mined throughout the world are of gem quality and the great bulk are used in industry for grinding and cutting. Diamonds are found in "pipes" in a substance know as blue ground, or in alluvial deposits such as the beds of streams. In some cases they are mined from the sea where the sand that contains them is sucked up from the sea-bed and filtered.
Through studies of carbon isotope ratios (simialr to the methodology used in carbon dating except with the stable isotopes C-12 and C-13), it has been shown that the carbon found in daimonds comes from both inorganic and organic source. Some diamonds, know as harzubigtic, are formed from inorganic carbon orignally found deep in the Earth's mantle. In contrast, eclogitic diamonds contain organic carbon from organic detritus that has been pushed down from the surface of the Earth's crust through subduction before transforming into diamond. These two different source carbons have measurably different 13C: 12C ratios. Diamonds that have come to the Earth's surface are generally very old, ranging from under 1 billion to 3.3 billion years old.
The cutting of diamonds has developed in order to show the stones at their best, the "brilliant" cut being the most effective. Diamonds have been cut in many different ways but their brilliance is sometimes sacrificed in order to produce a different shape of stone.