Pink diamond fetches $26.6 million at auction

Sotheby's had estimated that the flawless oval gem, "The Spirit of the Rose," could fetch between $23 millon and $38 million at the Geneva sale.

Bidding opened at 16 million Swiss francs and climbed to the final hammer price of 21 million Swiss francs, plus commission. It was bought by a telephone bidder who chose to remain anonymous, Sotheby's said.

The diamond was named after a ballet performed by the Ballets Russes and its legendary dancer Vaslav Nijinsky in 1911.

Naturally colored diamonds occur because they possess a particular lattice structure that refracts light to produce colored, rather than white, stones.