A graduated, three-strand coral necklace led Bonhams' San Francisco Salon Jewellery and Watches auction on March 25.
Estimated to be worth $6,000-8,000, the necklace sold with a 44.5% increase on its top valuation, for $11,500.
A group of three unmounted coloured diamonds also sold with strong results, bringing $11,250. Having been given the conservative top estimate of $2,500, the diamonds' sale price represents a 350% increase.
Lynn Arkin, a jewellery specialist at Bonhams, commented: "Colour was a big winner in this sale, along with signed pieces from Cartier, Schlumberger and Tiffany & Co."
With a 75 carat white diamond to cross the block at Sotheby's in April, and a D-colour flawless diamond to wow crowds at Christie's in May, strong diamond sales suggest the current world record for the most valuable colourless diamond at auction might soon be exceeded.
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