This unique piece of jewelry sold for 10-20% more than expected.

Originally from De Beers Millennium Collection, the diamond had been expected to sell for between £3 million and £3.8 million at Sotheby’s, but eventually sold for £4,221,533. The pear-shaped diamond, which had been owned by a private buyer, is one of 12 in a collection De Beers put together for the turn of the millennium, and was displayed at London’s Dome, now the O2 arena, in 2000. An attempt to steal the diamonds at the time was thwarted by the Metropolitan police. – From Telegraph