Interactive: A Diamond's Journey: The miners

updated 6/26/2009 7:55:57 PM ET 2009-06-26T23:55:57

The diamond mining industry is where the modern diamond’s story picks up. Companies like De Beers
For decades, De Beers, the world’s largest diamond mining company, ran a near monopoly of the international industry. By controlling over 80 percent of the world’s rough diamonds, the cartel was able to regulate the supply of rough stones on the market and dictate their costs at will.

Its dominance of the market has dissipated somewhat. In 1994 the U.S. Justice Department charged De Beers with antitrust violations for conspiring to fix prices. In 2004, De Beers pleaded guilty to the charges and agreed to pay a $10 million fine, ending years of outright market fixing.  

Despite the settlement, the company still controls roughly half the world’s supply of rough diamonds and sorts and sells them to 93 select clients or “sightholders” through the Diamond Trading Co. (DTC).

The development of new diamond mines in Russia and Australia – out of the reach of the South African company – has changed the market (although De Beers is investing heavily in Canadian mines). Lev Leviev, an Israeli entrepreneur, the world’s largest cutter and polisher of diamonds, is also cutting into De Beers’ supply of rough diamonds by securing his own mines in Russia and Angola.
, the world’s largest diamond mining company, based in South Africa, spend millions of dollars annually on the most advanced technology to do geological research to find diamond deposits on land and in the sea.

The two different types of diamond deposits – primary deposits and secondary deposits – require different mining techniques.  

To recover diamonds that are in primary deposits requires open pit or underground mining in which the ore is crushed in order to find the diamonds.

Secondary deposits, also referred to as alluvial deposits, are those that have been dispersed from their original source due to erosion, so they are often found on coastlines, ocean floors and riverbeds. Exploiting secondary deposits requires the excavation of sand or deep sea mining – including drilling into the seabed to find diamond-bearing stones.

De Beers, with diamond sales over $6 billion in 2005, has 15 mines across Africa and is constantly funding geological missions in search of more diamond deposits. Many of its mines are joint ventures with national governments. It produces more than 40 percent of the world’s rough diamonds annually.

But the mining of alluvial diamond deposits still takes place on a more informal scale referred to as “artisanal mining” by the diamond industry. It’s estimated that up to 1 million people in Africa make a living through small-scale mining that entails sifting through sand and gravel, often in riverbeds, with sieves and pans to find diamonds.

The diamond mining industry functions as a result of the search for gem diamonds, as well as diamonds for industrial use. But part of what fuels the search for diamonds is the elusive search for “the big one.”

To this day, enormous diamond discoveries are still made.
World’s biggest diamond finds:

The Cullinan, weighing in at 3,106 carats uncut (more than a pound), is the largest gem-quality diamond ever found. It was discovered in South Africa in 1905 and was cut into 11 gems and smaller pieces. Two gems cut from the Cullinan – the Great Star of Africa (530.2 carats) and the Lesser Star of Africa (317.4 carats) – are part of the British Crown Jewels on display in the Tower of London.

The second-largest diamond ever discovered is The Excelsior, discovered in South Africa in 1893 and weighing in at 995.2 carats. It was reportedly found by a mine worker as he was loading up a truck.

Another one of the world’s largest diamonds became the icon for one of America’s most revered jewelry houses – The Tiffany, a 287.42 carat diamond, was discovered in the Kimberley Mine in South Africa in 1877.

By comparison, the infamous Hope Diamond that is renowned for the misfortunes it brought on its various owners seems paltry, weighing in at a mere 45.42 carats. The “Lesotho Promise” – at 603 carats, the biggest diamond discovery in 13 years – was sold at auction in October 2006 for more than $12 million. Named for the small African nation where it was found in August 2006 the diamond was found at the Letseng Diamond Mine by a woman looking through rocks.

Sources: DeBeers,, Wikipedia,, PBS Nature, Economist


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