Photo: Tannis Toohey / Toronto Star Via Getty Images
(Bloomberg) – The largest diamond found in North America was discovered by Dominion Diamond Mines and Rio Tinto Group on a mine in Canada's frozen north.  The 552 carat white bead was found on the Diavik mine in Northwest Territories, and is almost three times the size of the second largest stone ever found in Canada. While Diavik and the nearby Ekati mine produce some very high quality diamonds, they are not known for the kind of big gems usually found in southern African mines.
Dominion CEO Shane Durgin said the diamond is pearl quality, which means it is suitable for jewelry, but gave some extra touches that help determine the value. Yellow stones usually sell at discount to Type IIa top white, which are often found in the best African mines. Nevertheless, the highest quality fancy vibrant yellow or fancy, intense yellow stones can sell for a premium.
"We can notice that bright yellow, but beyond that, due to its rough nature and wear received through the processing plant, that's all we can comment on," said Durgin in an interview. "It's very hard to give a ballpark estimation. It all depends, again, the cut and the resulting rock it ends."
The discovery is the seventh largest in this century, according to Bloomberg calculations, and will be among the 30 largest rocks which has been upgraded. The largest was 3,106 karat Cullinan, found near Pretoria in South Africa in 1905. It was cut in several polished beads, the two largest ones – the great star in Africa and the smaller star in Africa – is set in Crown Jewels or Britain.
There have been a number of major discoveries in recent years, as better technology helped miners first discover, and then did not break large stones that are prone to being broken in the mining process. Among them are diamonds found by Lucara Diamond Corp and Gem Diamonds Ltd. which brought between $ 40 million and $ 63 million.
While the Diavik mine is 60 percent owned and fully operated by Rio, Dominion bought the stone in an internal auction process from its partner. Dominion said it would pick someone to cut and polish the stone soon.
"It's a beautiful pearl-quality diamond," said Durgin, adding that it was something of a "miracle" that the stone survived the mining process. "It's very unusual for a diamond of this size in this part of the world. So it's a very unique discovery."
By 2015 Rio broke up a 187.7 carat pearl diamond diamond from Diavik. "Foxfire" snapped snugly and was powdered because the elongate shape allowed it to slide sideways through a filtering screen. The diamond was exhibited on Smithsonian before it was turned into a pair of pale yellow earrings weighing a total of 77.7 karat. The ears sold for over $ 1.5 million on Christie's earlier this month.
This year's discovery comes in time for Dominion. Since billionaire Dennis Washington bought the company for $ 1.2 billion last year, there has been a management-approved round of at least five senior executives. This includes CEO Patrick Evans, who left last week after just over a year at the helm. Dominion must decide whether it will pull the trigger on expansion projects that will extend the life of the Ekati mine.
Diamond extraction in this area of Canada's subark is incredibly difficult. There are no fixed roads, that is, the only access is in the air or for a few months a year, ice rivers that have to be built in the winter.
Meanwhile, the global market has been under pressure, especially for smaller and lower quality stones. There is currently an overuse of such diamonds, and a weaker Indian rupee has put pressure on producers in the country where about 90 percent of precious stones are cut and polished. Large centers of excavation have also been pushed by low margins and a decline in trade funding.
– With the help of Joe Richter.
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