World’s Coldest Inhabited Region Yields 390-Carat Gem-Quality Diamond

A 390.7-carat diamond unearthed at the Mayat mine in the Anabar region of Yakutia, near the Arctic Circle, is the second-largest diamond ever found on Russian territory and the largest in a decade.

Russian mining giant Alrosa reported on Sunday that the transparent "crystal has a non-standard shape and is bordered by a yellowish-brown halo." Alrosa credited the find to its subsidiary, Almazy Anabara, which scored the the massive gem during the night-time washing of the diamond sands at the Ebelyakh portion of the deposit.

Anabar, in the northernmost part of Yakutia, is said to be the coldest inhabited region in the world, where the average temperature in January reaches a high of -25°F and a low of -39°F. The basin of the Anabar river is has one of the largest concentration of diamond deposits in the world.

In a statement, Alrosa noted that the "combination of mass, shape and color makes the stone unique."

“The discovery of one of the largest diamonds in Russian history is undoubtedly an unprecedented event and an excellent finale to the 2023 mining season,” noted Alrosa CEO Pavel Marinychev. “Experts have yet to study in detail and evaluate the potential of the mined diamond and its characteristics, but, without a doubt, this is a record holder both for our company and for the country’s diamond industry.”

To the casual observer, the fractured edges of the gem hint that this specimen was once part of a larger stone that could have been crushed during the sorting process.

The miner added that a colorless 37.7-carat diamond with a more traditional octahedron shape was recovered at the same time.

According to Wikipedia's "List of the Largest Rough Diamonds," the Mayat-sourced gem now rates #52, while the slightly larger 401-carat Russian record-holder stands at #50. At the top of the list is the 3,106-carat Cullinan Diamond, which was discovered in South Africa in 1905.

Despite being one of the largest producers of diamonds in the world by volume — with deposits located in the Arkhangelsk region and the Siberian republic of Yakutia — Alrosa rarely reports super-large specimens.

Bloomberg noted that sanctions imposed against the state-controlled Alrosa due to the war in Ukraine could hamper a potential sale of the newly recovered stone.

Credit: Photo courtesy of Alrosa.