A 118.91 carat rough diamond was extracted earlier this month from the ‘International’ mine, which is recognised as having the world's highest carat content per tonne of ore mined, ALROSA said in an announcement yesterday. The stone is the largest gem-quality diamond found at the mine since the 109.61 carat diamond was mined in 2017.

The extracted rough diamond - with a light yellow overblown, has salient edges, one of them with cleavage, and small inclusions in the central zone, ALROSA stated.

“This crystal is unique as it has a large clean area despite the inclusions in the center - this makes it a gem-quality diamond. Well-known hallmarks of the diamonds from the ‘International’ kimberlite pipe are regular shapes and purity. That is exactly the pipe that most often brings ALROSA regular shape octahedrons with smooth edges,” explained Evgeny Agureev, Member of the Management Board, Director of the United Selling Organization at ALROSA.

As the diamond was mined on the eve of the launch of Zarya – a new deposit of ALROSA at Aykhal Mining and Processing Plant, the company has named it ‘Zarya’.

The International pipe, which was discovered in 1969 saw open-cast mining being conducted between 1971 and 1981. Subsequently, the underground mine was developed and mining commenced there in 1999. While its average content at the mine is 7 carat per tonne of ore mined, there are periods when this figure has reached as high as 12 ct/t, ALROSA said.

Pic caption: The 118.91 carat rough diamond extracted at the International mine

Pic courtesy: ALROSA