The Diamond Trading Company of DeBeers dictates who gets which diamonds. Prices are not negotiable. The price of different diamonds as classified by De Beers is fixed. You need to buy the entire box or you may have none at all. Clients are not allowed to resell the diamonds in the purchased box in their original uncut form without a permission coming from DeBeers.
If a merchant wishes to deal with DeBeers, then that merchant must supply DeBeers with whatever vital information necessary to assess the prevailing diamond market. The clients of DeBeers are not allowed to sell their diamonds to any traders, wholesalers or retail jewelers that would undercut the prices of the diamonds at the retail level.
The history of the global diamond industry shows how the business of diamonds was transformed from a loose collection of traders into one tightly organized cartel which controlled both the supply and price of diamonds. This is the case for the most part of the 20th century. However, new rules in the global marketplace are changing the landscape of the diamond industry. Only time will tell if the strong presence and control of the DeBeers over the global diamond industry would soon end. Whether it is good or bad for the industry is still something that lies to be seen in the future.
One important trait that made the diamond industry so successful was the famous marketing phrase that became a global hit, “a diamond is forever”. But some skeptics think that the control over the global diamond industry by the DeBeers and its cartel may not really be forever there.