GENEVA (AFP) - A 25.59 carat "pigeon blood" ruby sold for a world record US$30.34 million (S$40 million) at auction in Geneva on Tuesday while a rare pink diamond believed to have once belonged to Napoleon's niece fetched US$15.9 million, Sotheby's said.
After competitive bidding, the ruby went to an anonymous telephone bidder for 28.25 million Swiss francs (S$40 million), with costs.
The "Sunrise Ruby" from Myanmar, part of a collection of Cartier jewels up for auction, had been expected to sell for between US$12 million and US$18 million.
It set a record for a ruby and was also a record for a Cartier jewel at auction, Sotheby's said.
"The Sunrise Ruby sold for just over US$30 million, US$30.3 million, which is I think over three times the previous record, which was for the Graff Ruby," said David Bennett, head of Sotheby's international jewellery division, referring to a stone sold in November.
The large, pigeon-blood red ruby "is amongst the rarest of all gemstones".
"I mean, in 40 years I've ever only seen one this colour, this size, so they are beyond rare," Bennett said.
Another "extremely rare" stone, a fancy vivid pink diamond weighing 8.72 carats sold for 14.8 million Swiss francs at the spring Magnificent Jewels and Nobel Jewels auction.
The stone, known as "The Historic Pink" and mounted on a ring with a classic non-modified cushion cut, is believed to have been part of the collection of Princess Mathilde, niece of French Emperor Napoleon I, according to the Gemological Institute of America.
Another of its former owners was the reclusive American heiress and philanthropist Huguette Clark, who died in 2007.
It only recently reappeared after having been kept in the safe of a bank since the 1940s.
The origins of the stone remain unclear. The technical characteristics of the stone and the fact that it is so old suggest it may have been found in the famous Golconda mines of India, according to Bennett.
The market for coloured diamonds and precious stones has never been so dynamic, according to Sotheby's, with pink diamonds among the rarest.
In October 2014, Sotheby's sold a 8.41 carat pink diamond, which was cut differently, for US$17.8 million.
At Tuesday's auction, a pair of Cartier earrings with sapphires from Myanmar and diamonds sold for 3.4 million Swiss francs.
Rival auction house Christie's will be hosting its spring jewels auction in Geneva on Wednesday.
It said that among the 351 pieces to go under the hammer is the Maria Christina Royal DevantdeCorsage diamond brooch, a wedding gift from Spanish king Alfonso XII to his wife, Austrian archduchess Maria Christina in 1879.