RAPAPORT... Alrosa increased its rough-diamond prices by around an average of 7% at this week's contract sale, customers of the miner told Rapaport News.The hikes impacted the full range of Alrosa's goods, though they were steeper for sizes above 2 carats, with some categories up by more than 10%, the clients said. The miner also adjusted its assortments, making some boxes appear significantly more expensive.The move at the July trading session followed De Beers' increase of an estimated 4% to 5% at its sight earlier this month. Prices have strengthened in recent months because of solid consumer sales and shortages throughout the supply chain, De Beers said Thursday.Rough has been in short supply since the second quarter because of production limitations at De Beers and the fact that it and Alrosa depleted their inventories in the first three months of 2021. Alrosa's rough-price index surged 16% during the first six months of the year, while De Beers' rose 14%, the companies reported in recent trading and earnings reports.The Russian miner's hikes were sharper than expected, said one rough buyer. Further price rises are unlikely for the rest of the year, "because there is no [more] room to increase," he added. "In the last month, the polished market has [seen] a slowdown. It's not like the way it was in the first six months of the year."Alrosa declined to comment on prices, but said it ensured they reflected midstream demand.The company "remains committed to a prudent approach when it comes to managing its sales and pricing strategy, as [a] healthy and sustainable market balance in the long term is considered as our main priority," a spokesperson added.Last week, Alrosa bought around 70% of goods available at an auction by Gokhran - Russia's state gem depository - to help meet demand at this week's sale.Alrosa is scheduled to release results of its July sale on August 10. De Beers garnered $510 million at its July session - the highest since February.Image: A rough diamonds. (Alrosa)