North of 60 Mining News - The mining newspaper for Alaska and Canada's North

Dominion Diamond Mines Dec. 13 said the largest known gem quality diamond ever found in North America was unearthed at Diavik, a mine in Northwest Territories owned 40 percent by Dominion and 60 percent by Rio Tinto.

Weighing in at 552 carats, this yellow diamond is nearly triple the size of the next largest diamond recovered in North America, a 187.7 gem found at the same mine known as the Diavik Foxfire.

The astonishing gemstone was uncovered while passing through the initial screening process at Diavik's recovery plant. Abrasion markings on the stone's surface attest to the difficult journey it underwent during recovery, and the fact that it remains intact is remarkable.

Measuring 33.74 by 54.56 millimeters (1.33 by 2.15 inches) and weighing exactly 552.74 carats, this roughly chicken egg sized diamond is completely unexpected for this part of the world and marks a true milestone for diamond mining in North America and Canadamark diamonds overall.

Canadamark is a program that assures the integrity of the supply chain of Canadian diamonds from mine to retail, providing diamond jewelry customers confidence in the origin and history of their polished diamonds bearing the Canadamark symbol.

"This incredible discovery showcases what is truly spectacular about Canadamark diamonds," said Dominion Diamond Mines Chairman Kyle Washington. "The color and texture of the diamond are a unique example of the journey that natural diamonds take from their formation until we unearth them. Our Diavik Mine has produced some of the most beautiful diamonds in the world, and this one certainly tops the list."

Its color, texture and structure are unique from a geological perspective and may be studied further.

Rio Tinto

A truck travels an ice road under the Aurora Borealis near the Diavik, a mine in Northwest Territories that has produced the two largest gem quality in North America.

Dominion said the diamond will not be sold in its rough form. Due to the significance of the discovery, is selecting a partner in the coming weeks who will cut and polish the stone. The size and highly technical nature of this stone means that only a handful of master cutters in the world are qualified to polish it, ensuring that the stone's beauty, color and brilliance are maximized.

Dominion expects to achieve a significant main stone once the diamond is polished, that will be Canadamark certified. As the diamond is still undergoing evaluation, it is too early to determine the ultimate value of the diamond. However, when polished, the Diavik Foxfire yielded a 37.87 brilliant-cut pear shape and a 36.80 brilliant-cut pear shape that were both recently auctioned as part of Christies Magnificent Jewels and were purchased for US$1.3 million.

–SHANE LASLEY