Alrosa, the world's top diamond miner by output, has found a 236-carat rough diamond of deep amber colour at one of its mines in Russia's northeastern region of Yakutia.
The precious stone, thought to be between 120 and 230 million years old, is the largest coloured diamond ever mined in Russia, the company said.
The diamond, described as having a "natural and intense yellow-brown colour," was found at Alrosa's Ebelyakh mine.
"Such a large natural colour rough diamond is a unique discovery," Pavel Vinikhin, head of diamonds at the company's cutting and polishing division, said in the statement.
Alrosa's specialists are currently evaluating the find. After that, the company will decide whether to give it to its manufacturers for cutting or sell it as a rough.
The diamond gem, measuring 47x24x22 millimetres, could be turned into several high-quality polished diamonds, the miner said.
This not the first time a rough colour diamond has been unearthed at the Ebelyakh deposit. In just one month in 2017, three unique stones of intense yellow, pink and purple-pink colors were discovered there.
Diamond miners and traders have been hit hard in the past two years by weak market conditions and the coronavirus pandemic. Analysts have warned that investment banks are increasingly reluctant to extend credit to diamond producers, as inventory is not being sold and defaults are possible.
"We are concerned about oversupply of rough diamonds following the reopening of economies, as a lot of inventory could potentially be flooded into the system and the market might not be able to absorb all of it, resulting in increased pricing pressure," Citi said in May.