Central Selling Organization (CSO)
The most common route is through the channels of DeBeers’ Central Selling Organization (CSO). Diamond Trading Company which are mined from De beers owned mine to CSO diamonds. CSO has purchase offices in various diamond producer countries. The Diamond Trading Corporation’s purpose is to stabilize prices when times are hard, and raise them with inflation and demand when times are good. The DTC holds ten week-long selling sessions called sight each year. These sights are by invitation only, and only a handful of diamond manufacturers from around the world (called sightholders) are allowed to attend. The value of each sight varies from US$500,000 to US$2,000,000. There are approximately 93 sightolders in the world.
The «outside» market is the market «outside CSO», i. e. not controled by De Beers.
Diamond exchange, bourse
The major diamond manufacturing centers includes Israel, Belgium, India and New York. The most important is Antwerp in Belgium, more than half of the world market of polished diamonds passes by Antwerp.
In Belgium, approximately 1,500 diamond offices are located in Antwerp in a diamond district: Hoveniersstraat, Schupstraat, Rijfstraat and Pelikaanstraat. The rough is distributed to the cutting centers and to dealers in Antwerp, where approximately 80-85% of the total rough diamond trade takes place. The main diamond bourses in Antwerp are:
Anwerp Diamond Bourse. Beurs voor Diamanthandel: polished diamonds.
Diamond Club: polished and rough diamonds.
Vrijediamanthandel: polished and rough diamonds.
DiamantKring: rough diamonds.
The conditions to become member of one of these bourses are very strict.