MOSCOW, October 4. /TASS/. Russia’s top miner Alrosa unearthed a double diamond in Yakutia, estimated by researchers to be more than 800 million years old, the company reported on Friday.

The gemstone has an unusual structure, with one diamond freely moving inside the other one. The gem therefore looks like a traditional nesting doll. This unique diamond is the first of its kind ever in the industry’s history, specialists say.

Despite its complex structure, the diamond’s weight is just 0.62 carats, Alrosa reported. The space of the inner cavity is 6 cubic millimeters and the weight of the diamond nesting inside is 0.02 carats.

Alrosa mines diamonds in the Sakha (Yakutia) and Arkhangelsk Regions. In 2018, the mining giant produced more than 36.6 million carats of gemstones, while selling more than 38 million carats. In addition, the producer rang up $4.5 bln in sales revenues.