The ruble has fallen due to Western sanctions against Russia and dropping oil prices which has slashed the government's income.
Russian diamond mining giant Alrosa reported an 8% rise in revenue in 2015 to $3.17 billion.
That came despite a 24% drop in sales volumes, and was a result of a "favorable FX [forex] market environment", the miner said.
The miner's net income for 2015 was $455 million compared to a net loss of $237 million in 2014.
PJSC Alrosa CEO Andrey Zharkov said: “After a decline in rough diamond market activity in the second half of 2015, we note signs of recovering market demand for the company’s main products.
"Alrosa's strong 2015 financial results were supported by both a favorable FX market environment and the company’s cost control initiatives,” he said.
