The Diamond Trading Company (DTC) is a London-based subsidiary of the De Beers Group, specializing in the sale and marketing of rough (uncut) diamonds. The company forms an essential part of De Beers' sales mechanism, maintaining an exclusive list of sightholders to which it sells all De Beers gem-grade diamonds coming to the market in a limited number of sales per year. Nicky Oppenheimer is chairman of DTC.

DTC receives uncut diamonds from all of De Beers' mines around southern Africa, as well as some production from Alrosa in Russia. The diamonds are then sorted into over 16,000 categories, according to size, color, clarity, carat and quality (amount of inclusions). They are then combined into lots for sale to sightholders. Sightholders are invited to DTC's London offices ten times per year and are given the opportunity to purchase lots of diamonds at prices set by DTC. According to a January 13, 2004 DTC media release ([1]), there are 84 sightholders, and three additional companies authorized to purchase diamonds from DTC for industrial use. In 2004, DTC's sales were $5.7 billion, an increase of 3.2% over the previous year.

DTC also operates De Beers' famous diamond marketing campaigns to consumers.

Diamond Sources Country

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 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.