Irregular purchases may lead to exclusion from the list. For diamonds under 14.8 carats, prices set are not negotiable. The sorted and graded diamonds are placed in boxes marked with the name of the purchaser and the price. Stabilization of the supply of rough and thus of prices by the CSO is accomplished in three ways: allocation of production quotas for the mines with a guaranteed minimum quota sufficient to secure continuity of production, regardless of the state of the world market 10 yearly offerings of rough, known as 'sights' to about 150 cutters and dealers in the various diamond centers and accumulation of stocks when demand cannot sustain the prices until the market improves. As new discoveries of diamond deposits and sales independent of CSO are expected, the monopoly power of DTC will continue to decline. The DTC still has a substantial position in the distribution of the rough, controlling about 50 percent of the world output, down from 80 percent in the 1980s, through the exploitation of its own mines (these account for over 40 percent of world output) or through purchasing contracts with independent diamond producers. The present-day successor to the original syndicate and the Central Selling Organization (CSO), which was reorganized by Ernest Oppenheimer in 1929, is the Diamond Trading Company (DTC). In the aftermath of the 1893 market collapse, Cecil Rhodes succeeded in consolidating the majority of the South African diamond mines within DeBeers Mines and formed the London Diamond Syndicate. The modern economic origin of the diamond industry is the outgrowth of the two depressions in 1893 and in 1929.

Whole sale cyndicate rough diamond