(IDEX Online) - Alrosa has reportedly followed De Beers by discounting rough prices in response to the coronavirus slump in demand.Last week De Beers was reported to have lowered the price of larger stones at Sight 7 by as much as 10 per cent.Both miners have held firm with sales-over-volume policies until now, despite smaller rivals offering discounts of up to 25 per cent. De Beers and Alrosa jointly control half the world's supply of diamonds.Alrosa, the Russian state-owned miner, has also changed its billing system to that buyers can't tell which stones have been discounted or by how much, according to a report on the Bloomberg financial news website.Meanwhile, Alrosa says it sold 1,700 of the 2,300 carats of special-size rough diamonds (+10.8 carats) offered during its August digital auction."The results of the digital auction show that the market participants have adapted to work in a new reality," said deputy CEO Evgeny Agureev."During the August auction of special-size rough diamonds, we sold more than three quarters of the auctioned lots by units as well as by weight."This result is a good evidence of the recovery of the demand for the high quality rough; and demonstrates that this new sales channel, which perfectly complements traditional ones, is gradually accepted by the market."Pic shows diamond sorting, courtesy Alrosa