S. Africa solidifies diamond sway

Diamonds may last forever, but not far behind in staying power is the near-monopoly on the world diamond trade enjoyed by De Beers Consolidated Mines of South Africa.

Despite assaults on De Beers from producers who feel they might earn more going it alone, or who find business ties with South Africa distasteful, the De Beers grip on the trade is holding strong. Its latest victory is the decision by Zaire to return to the fold, Monitor correspondent Paul Van Slambrouck reports. Zaire decided to market its own diamonds in 1981, bypassing the De Beers Central Selling Organization (CSO), which markets some 80 percent of the world's diamonds under exclusive contracts with producers.

Zaire's new contract for the CSO to market all diamonds from the Miba mine - the country's major source of diamonds - has both economic and political overtones, say diamond-industry analysts. Its apparent failure to earn more by selling its diamonds independently may warn other nations - particularly those in black Africa - against severing business ties with South Africa as a gesture of opposition to its racial policies.

The diamond market has been in what is considered its worst slump in 50 years. Sales of high-grade diamonds were especially hurt by high interest rates and recession in the West. But with signs of recovery appearing, some industry analysts forecast improved sales.