The partners recovered the chicken-egg-sized, 552-carat stone in October, surpassing the size of the previous record holder, the 187.7ct Diavik Foxfire, by a significant margin.
Dominion said abrasion markings on the stone's surface attested to the difficult journey it underwent during recovery, and the fact that it remained intact was remarkable.
"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," Dominion chairman Kyle Washington said.
The precious gem measures 33.74mm-by-54.56mm and weighs 552.74ct.
Dominion conceded a diamond of this size was completely unexpected for this part of the world and marked a "true milestone" for diamond mining in North America and 'Canadamark' diamonds overall.
The diamond's colour, texture and structure are also unique from a geological perspective and may be studied further.
Dominion said the diamond would not be sold in its rough form, and it would select a partner in the coming weeks to cut and polish the stone. Dominion expected to achieve a significant main stone once the diamond was polished, that would be certified under the Canadamark brand.
The company said it was too early to assign any monetary value to the find, but when polished, the Diavik Foxfire yielded two brilliant-cut pear shapes weighing 37.87 and 36.80cts each. Both recently auctioned as part of Christies Magnificent Jewels and were purchased for US$1.3 million.