The Graff Pink

The Graff Pink is a rare 24.78-carat pink diamond that was originally owned by Harry Winston, an American famous jeweler. Sotheby's auctioneers in Geneva, Switzerland, sold the diamond in a ring on November 16, 2010. The diamond was predicted to enter the top 10 most costly diamonds in the world prior to its sale; nevertheless, after selling for US $46 million (£29 million), it became the most expensive single jewel ever sold at auction at the time.

The diamond is rated as "fancy strong pink" by the Gemological Institute of America—a high color grading for pink diamonds—and has been assessed as Diamond type IIa, putting it in the top 2% of the world's diamonds.

The diamond's early history is obscure. It was sold in the 1950s by American famous jeweler Harry Winston to a private collector, who kept it until it was auctioned off in 2010. Despite its rarity, the diamond remained nameless for many years. The diamond is emerald cut with softened sides and set in a platinum ring with two shield-shaped diamonds flanking it.

Price: $46 million