Profits at De Beers have slumped in what it calls the "most difficult" economic environment in decades.
In the first six months of 2009, the world's biggest diamond producer made a profit of $US3 million, down from $US316 million a year earlier.
The BBC reports demand is weak in the United States, but many in China and India are still buying.
De Beers has cut production this year and will produce roughly half the amount of carats in 2009 that it did in 2008.
Production at mines in South Africa, Canada, Botswana and Namibia was 73% lower in the first six months, than last year at 6.6 million carats.
The company has reduce the inventories of rough diamonds in cutting centres by 30%. It has also shrunk its global workforce by 23%.