Graff Pink diamond
It has been graded a VVS2 clarity, type IIa, fancy intense pink diamond by the Gemological Institute of America (GIA).
The diamond is a classic emerald cut with gently rounded corners. It has few inclusions and a homogenous colour.
The GIA states that the diamond may be “potentially flawless” after repolishing although some commentators state that there is a single flaw that is unnoticeable to the naked eye.
The diamond is set between shield-shaped diamond shoulders, in platinum, as a ring, size 55½.
The early history of the diamond is not clear.
It was once the property of American jeweller Harry Winston but was purchased in the 1950s by a private collector and remained off the market until 2010.
Despite its rarity, the diamond was unnamed until Laurence Graff purchased it.
The diamond was sold to British dealer Laurence Graff in Geneva in November 2010.
Graff is the owner of Graff Diamonds. Graff bought the Wittelsbach-Graff blue diamond in 2008 for a then record auction-house price of £16.4 million.
Sotheby’s had attached a $27-38 million estimate to the Graff Pink prior to the sale.
David Bennett, the head of Sotheby's jewellery division, told the BBC at the time of the auction: "There's only one or two other stones I've seen like this in the 35 years I've been doing this job. I just love it."