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DIAMONDS A TO Z - The Diamond Industry

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The Diamond Industry

The diamond industry consists of segments that mines, processes and markets gem diamonds and industrial diamonds.

Gem quality diamonds are mined primarily in Botswana, Russia, South Africa, Angola, Namibia, Australia and the Democratic Republic of the Congo.

It takes an average of 250 tons of mined ore to produce one carat of finished diamond.

the primary diamond processing centers, where they are evaluated, cut and sold are in Antwerp; India, Tel Aviv and New York.

Unlike precious metals such as gold or platinum, gem diamonds do not trade as a commodity: there is a substantial mark-up in the sale of diamonds, and there is not a very active market for resale of diamonds. One hallmark of the trade in gem-quality diamonds is its remarkable concentration: wholesale trade and diamond cutting is limited to a few locations.

92% of diamond pieces cut in 2003 were in Surat, Gujarat, India. Other important centers of diamond cutting and trading are Antwerp, London, New York, Tel Aviv, Amsterdam.

More than 50% of the world's production of rough, polished and industrial diamond passes through Antwerp.

8 in 10 of all rough diamonds in the world are handled in Antwerp.

1 in 2 of all cut diamonds passes through Antwerp.

The Antwerp diamond sector has an annual turnover of 39 billion U.S. dollars.

The diamond trade is responsible for 8% of Belgian exports, and 12% of the Flemish region's exports.

30.000 people are directly or indirectly employed by the Belgian diamond sector.

The figures speak for themselves. Antwerp has created an international commercial platform upon which producers, manufacturers and traders from all over the world can meet.

Antwerp is the world's diamond capital but there are other large centers such as the Indian production hubs of Mumbai and Surat; Israel is a complementary trade centre, mainly supplying North America. Dubai is the regional distribution centre for the Middle East. New York is the primary port of entry into the United States, and the largest market for diamonds in the world.

A single company, De Beers, controls a significant proportion of the production and trade in diamonds. They are based in Johannesburg, South Africa and London, England.

Modern exploration uses highly sophisticated technologies to determine the economic viability of deposits. Examples include airborne surveys.

Geophysicists carry out the Ground Geophysical surveys, which are used as a follow-up tool to detect and improve definition of anomalies associated with kimberlite intrusions. Most exploration teams have one or more geophysicists helping to manage the application of appropriate geophysical techniques and interpretation of data. Frequently used geophysical methods include:

  • Magnetics (both airborne and ground)
  • Airborne multi-spectral analysis (AMS)
  • Various suites of electro-magnetics
  • Gravity
  • Radiometrics
  • Seismics

Approximately 5,000 kimberlites are currently known in the world, but only 100 or so of these contain sufficient diamonds to be of economic interest. In most of those deposits that are of interest, diamond is present in concentrations of less than about one part in five million.

Kimberlite, alluvial and marine mining use different techniques. Kimberlite mines are underground or open-pit. Alluvial stones may be mined commercially or on a small scale. Marine alluvial mining involves specialised ships. Diamonds are mined on all continents.

Once diamonds are detected, there are different types of mining operation used to extract them depending on the environment in which they are found. The majority of diamonds are extracted on an industrial scale by open pit mining and underground mining.

Open pit mining is excavation to reach diamonds on the surface of the ground. Underground mining is excavation up to and, in some instances, over 1km below ground.

Following extraction, the ore containing the rough diamonds goes through many stages of crushing and processing before it can be sorted and classified.

Diamonds are also extracted from alluvial deposits, where they are removed from sand, gravel and clay that has been naturally transported by water erosion and deposited along either the banks of a river, the shoreline or on the bed of the ocean. This process is called alluvial mining and is undertaken on an industrial scale by coastal and inland mining, which is removal of overburden, such as sand and soil, to find diamonds; and by marine mining, which is excavation of diamonds from the seabed.

Diamond mining on a non-industrial scale is undertaken involving individuals, families and communities and using the most basic equipment, such as sieves and pans - this is known as artisanal digging.

Rough diamonds are sorted based on characteristics such as shape, size, colour, cuttability and quality. The Diamond Trade Company (the distribution arm of De Beers) sorts and distributes 45% of the world's rough diamond supply. The balance is sorted and sold in centres such as Antwerp and more recently Mumbai. The DTC exclusively sells to 93 clients that are called "Sightholders".

Once processed at the mine, rough diamonds are typically delivered to sorting experts to be sorted and valued into 12,000 different categories in preparation for sale.

These categories are dependent on size, shape, quality and colour. The majority of diamonds fall within a range of standard colours from colourless to faint yellow or brown tints. Some very rare diamonds, known as "fancies", are bright colours, such as pink, blue or green.

A perfectly transparent diamond with no colour or hue is considered to be the purest, but all rough diamonds have some distinguishing marks, known as inclusions, which make each one unique. The Diamond Trading Company sorts, values and sells around half of the world's rough diamonds - selling in excess of $6 billion worth of diamonds a year.

The best quality diamonds in terms of colour and clarity are distributed to the gem market with an accompanying Kimberley Process certificate to prove that they are from conflict free sources. The remainder are ultimately used for industrial purposes, such as cutting and drilling.

The DTC's clients - known as "Sightholders" - are among the world's leading diamantaires, and are carefully chosen for their ability to add value to the diamonds sold by the DTC. Based mainly in the traditional cutting centres of Antwerp, Tel Aviv, Mumbai, Johannesburg and New York, as well as in Botswana, Namibia, Russia, China and Thailand, these Sightholders attend the DTC's Sights, or sales weeks, which occur ten times a year. Through its sales process, the DTC is able to offer its clients a consistent supply of diamonds in a range of assortments.

The DTC is the world's leading developer and producer of diamond technology and operates a dedicated Research and Development facility. The work of the DTC's Research Centre is undertaken to support the consistency of DTC rough diamond assortments for its clients and the sustainability of downstream industries in the DTC's producer country partners.

The production and distribution of diamonds is largely consolidated in the hands of a few key players, and concentrated in traditional diamond trading centers noted above.

New York, however, along with the rest of the United States, is where almost 80% of the world's diamonds are sold, including at auction. Also, the largest and most unusually shaped rough diamonds end up in New York.

De Beers, as the world's largest diamond miner and distributor, holds a clearly dominant position in the industry, and has done so since soon after its founding in 1888 by the British imperialist Cecil Rhodes. De Beers owns or controls a significant portion of the world's rough diamond production facilities (mines) and distribution channels for gem-quality diamonds. The company and its subsidiaries own mines that produce some 40 percent of annual world diamond production. At one time it was thought over 80 percent of the world's rough diamonds passed through the Diamond Trading Company (DTC, a subsidiary of De Beers) in London, but presently the figure is estimated at less than 50 percent.

The De Beers diamond advertising campaign is acknowledged as one of the most successful and innovative campaigns in history. N. W. Ayer & Son, the advertising firm retained by De Beers in the mid-20th century, succeeded in reviving the American diamond market and opened up new markets, even in countries where no diamond tradition had existed before. N.W. Ayer's multifaceted marketing campaign included product placement, advertising the diamond itself rather than the De Beers brand, and building associations with celebrities and royalty. This coordinated campaign has lasted decades and continues today; it is perhaps best captured by the slogan "a diamond is forever".

Processing takes place in 30 countries but is concentrated in five locations: Antwerp, Johannesburg, Mumbai, New York and Tel Aviv. India processes 55% by value of the world's diamonds. China and Thailand are increasingly active centres.

Diamond cutting is a great skill, practiced for generations. The natural form of a diamond will determine the shape of the final polished diamond. A standard round brilliant cut, with 57 or 58 polished facets, is based on the original shape of an octahedral crystal.

Gem quality diamonds are usually distributed to one of the main diamond cutting and trading centres in Antwerp, Mumbai, Tel Aviv, New York, China, Thailand or Johannesburg. Once they arrive at the diamond centres, experts (known as "diamantaires") cut and polish the rough diamonds into shapes, such as the round brilliant, the oval, the pear, the heart and the emerald.

Polishing follows cutting, before the diamonds are again classified by their cut, colour, clarity and carat weight - also known as the "Four Cs". These diamonds are typically sold to diamond wholesalers or diamond jewellery manufacturers in one of the 24 registered diamond exchanges (known as bourses) located across the world.

Members of The World Federation of Diamond Bourses (WFDB) act as a medium for wholesale diamond exchange, trading both polished and rough diamonds. The WFDB consists of independent diamond bourses in major cutting centres such as Tel Aviv, Antwerp, Johannesburg and other cities across the USA, Europe and Asia.

In 2000, the WFDB and The International Diamond Manufacturers Association established the World Diamond Council to prevent the trading of diamonds used to fund war and inhumane acts.
WFDB's additional activities also include sponsoring the World Diamond Congress every two years, as well as the establishment of the International Diamond Council (IDC) to oversee diamond grading.

The market for industrial-grade diamonds operates much differently from its gem-grade counterpart. Industrial diamonds are valued mostly for their hardness and heat conductivity, making many of the gemological characteristics of diamond, including clarity and color, mostly irrelevant. This helps explain why 80% of mined diamonds (equal to about 100 million carats or 20,000 kg annually), unsuitable for use as gemstones and known as "bort", are destined for industrial use. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 3 billion carats (600 metric tons) of synthetic diamond is produced annually for industrial use.

The dominant industrial use of diamond is in cutting, drilling, grinding, and polishing. Most uses of diamonds in these technologies do not require large diamonds; in fact, most diamonds that are gem-quality except for their small size, can find an industrial use. Diamonds are embedded in drill tips or saw blades, or ground into a powder for use in grinding and polishing applications. Specialized applications include use in laboratories as containment for high pressure experiments (see diamond anvil), high-performance bearings, and limited use in specialized windows.

With the continuing advances being made in the production of synthetic diamonds, future applications are beginning to become feasible. There is speculation about the possible use of diamond as a semiconductor suitable to build microchips from, or the use of diamond as a heat sink in electronics.


What is a diamond

Material properties

Natural history - How diamond is formed

History of diamonds

The diamond industry

Blood diamonds


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