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Colored diamonds headline twin auctions in Geneva this week

FILE - In this Nov. 4, 2015 file photo a Sotheby's employee displays the rare Blue Moon Diamond during a preview at Sotheby's, in Geneva, Switzerland. The 12.03 carat blue diamond is the largest cushion shaped fancy vivid blue diamond ever appear at auction. It is estimated to sell between 35 and 55 million US dollars. The auction will take place in Geneva, on Nov. 11, 2015. (Martial Trezzini/Keystone via AP, file) FILE - In this Nov. 4, 2015 file photo a Sotheby's employee displays the rare Blue Moon Diamond during a preview at Sotheby's, in Geneva, Switzerland. The 12.03 carat blue diamond is the largest cushion shaped fancy vivid blue diamond ever appear at auction. It is estimated to sell between 35 and 55 million US dollars. The auction will take place in Geneva, on Nov. 11, 2015. (Martial Trezzini/Keystone via AP, file)

By Associated Press November 9, 2015 1 min read

GENEVA (AP) – Highly valued colored diamonds go under the auction hammer this week in Geneva, with one standout blue diamond expected to fetch up to $55 million.

On Tuesday, Christie’s starts the two-day blitz of jewelry sales at an auction headlined by “The Pink,” a 16.08-carat diamond billed as rare for pure color. Its estimated pre-sale price is between 21 million and 27 million Swiss francs ($23-28 million).

Sotheby’s expects to fetch $35-$55 million a day later with the sale of the 12.03-carat Blue Moon Diamond, said to be among the largest known fancy vivid blue diamonds.

Spokeswoman Margaux Donckier of the Antwerp World Diamond Center said slower economic growth in places like China has softened the diamond market, but auctions of such “exceptional” pieces was likely to defy standard market forces.