An "astonishing gemstone" unearthed in a Canadian mine in October is the largest diamond ever found in North America, CNN reported.

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The 552-carat yellow diamond was found in Canada's Northwest Territory at the Diavik Diamond Mine, according to a news release from Dominion Diamond Mines.

The diamond measures 33.74 millimeters by 54.56 millimeters, the company said in its release.

That tops the previous record held by the "Diavik Foxfire," a 187.7-carat diamond discovered in 2015 at the same mine by the Rio Tinto mining company, CNN reported.

"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," Dominion Diamond said.

The diamond will not be sold in its rough form, the company said.