Russian diamond mining company Alrosa said on Thursday its net profit rose to 22.2 billion rubles ($409 million) in the first quarter of 2015, up almost fourfold year-on-year because of higher diamond prices and a weaker ruble.
Alrosa, the world's top producer by output in carats, recorded a 16.8 billion ruble loss last year, as the tumbling value of the rouble prompted a revaluation of the dollar-denominated part of its debt.
But the company said average diamond prices had increased 4 percent year-on-year, driving sales and supporting margins.
"The growth of gem-quality rough diamond sales was driven by a higher average diamond price ... and by rouble depreciation against the U.S. dollar," Alrosa said in a presentation to investors.
Earnings before interest, taxation, depreciation and amortization (EBITDA) rose to 42.9 billon rubles, up 65 percent compared to the previous year, the company said. Revenue increased 31 percent to 74.6 billion rubles.
The miner has previously said it expects net income of 100 billion rubles in 2015 and to increase sales by one percent, taking advantage of rising production and using offtake from its stock.