The sixth sales cycle was confirmed at US$116mln, while the seventh was pencilled in for a provisional US$320mln.
This would be up on the US$287mln from the seventh sales cycle last year, but comes after the first half of the year saw the coronavirus pandemic have a major impact on the diamond market.
In March, De Beers was prevented from holding its third rough diamond 'sight' of the year as public health restrictions on the movement of people and product in Botswana, South Africa and India prohibited customers from travelling and prevented the shipment of goods.
In the FTSE 100 miner's half-year results to June 30, 2020, De Beers rough diamond sales volumes fell 45% to 8.5mln carats, with revenues of US$1bn compared to US$2.3bn the year before.
Rough diamond sales were affected by lockdowns and travel restrictions, delaying the shipping of rough diamonds into cutting and trading centres and preventing buyers from attending sales events, the company said at July’s results.
Since lockdown opened up in China there had been strong diamond jewellery sales, though De Beers said a recovery in the US is dependent on the level of reopening of its economy.