The world's priciest diamond?

The Blue Moon Diamond
Source: Sotheby's

Time to start searching for that perfect Christmas gift? It's your lucky day, big spender—one of the world's most expensive diamonds goes up for auction in November.

A rare 12-carat, blue-colored diamond, known as Blue Moon, is expected to fetch $35 million to $55 million in a Nov. 11 Geneva auction, international auction house Sotheby's said Thursday.

If it does fetch that price, it would be the most expensive blue diamond ever sold, beating the Zoe Diamond, which sold for $32.6 million in 2014, Sotheby's said. To set the world record price for any diamond put to auction, Blue Moon must sell for more than $46.2 million.

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The South African diamond has garnered high critical marks, including the official, prestigious designations of "fancy vivid blue" and "internally flawless" by the Gemological Institute of America.

The moniker Blue Moon is a reference to the idiom "once in a blue moon," a hat tip to the rarity of finding a diamond of that shade and clarity, Sotheby's said.

If Blue Moon is out of your price range, never fear. Other notable colored diamonds Sotheby's has sold come in at a mere $16 million to $30 million.

Click here to read more about the diamond.