GENEVA - A 17.07-carat pink diamond sold for a hammer price of 18.3 million Swiss francs ($18.3 million) at a Geneva jewelry auction Wednesday, cruising past both its pre-sale estimate and the winning bid for the "Sky Blue" diamond billed as the event's standout piece.

The step-cut pink diamond, set in a ring between triangular white diamonds, had been expected to draw a maximum of 14.76 million francs. Instead, it sold at Sotheby's for more than the 8.01-carat "Sky Blue" diamond, which carried a pre-sale estimate of up to 25 million francs and went for 15 million.

The auction house had advertised the "Sky Blue" as the centerpiece item of the sale, trumpeting the top-level Fancy Vivid Blue grade the diamond garnered from the Gemological Institute of America.

Bidders outright snubbed two Russian imperial jewels that were expected to fetch 3-5 million francs each. Drawing dismissive oohs from the posh crowd at a lakefront Geneva hotel, the historic pieces failed to clear their minimum sale prices.

The jewels have origins in the vast collection of the imperial Romanov dynasty and once were held in the "Diamond Room" of the Winter Palace in Saint Petersburg. One, a diamond necklace with bowknot clasp, was said to have been commissioned by 18th century monarch Catherine the Great.

It garnered a top bid of 2.3 million francs.

"No more?" auctioneer David Bennett said before the hammer came down. "It will return to the owner... it was unsold."

The other rejected Russian lot featured a diamond parure, or matching set, which may have been part of a gift presented by the wife of Peter the Great to Ottoman Sultan Ahmed III as part of peace negotiations. The top bid for the set, which included a necklace, a brooch and a pair of earrings, was 2.7 million francs.

Including the buyer's premium, the pink diamond ring sold for $20.8 million and the "Sky Blue" went for $17.1 million. Overall, the auction brought in more than $136 million.

Wednesday's auction came a day after Christie's reaped about $97 million in its own Geneva jewelry auction that was highlighted by pear-shaped white diamond earrings and a pear-shaped pink diamond ring.

News from © The Associated Press, 2016