The Premier Blue, the world's largest fancy blue diamond, could set a record per-carat price when it auctions through Sotheby's on October 7 in Hong Kong.
The fancy vivid blue diamond, weighing 7.59 carats and internally flawless, is the only example of its kind of any significance to ever appear at auction. It is expected to see around $19m, according to Sotheby's Quek Chin Yeow in an interview with the New York Times.
Sotheby's currently holds the record per-carat price for a fancy vivid blue diamond at auction, which was set by a 6.01-carat example in 2011 at $1.6m per carat. The record for any blue diamond is held by a fancy deep blue example at $10.4m, which sold through Sotheby's Geneva in November 2012.
The sale follows two high-profile jewellery heists in Cannes, which inspired our Top 10 jewellery and diamond heists list.