Blue diamond ~ This is one of the rarest gems in the world - a 6.04 carat diamond that is fancy vivid blue color and has internally flawless clarity. The expensive stone was bought by a British jeweler for a record-breaking sum of almost £4 million at a Sotheby's auction in Hong Kong. The selling price makes it the most expensive gemstone in the world, per carat, sold at any auction. The flawless blue diamond fetched £650,000 per carat after intense bidding.
The Graff Pink -- Classified by the GIA as "fancy intense pink" and has been assessed as Diamond type IIa, placing it in the top two per cent of the world's diamonds! The early history of the diamond is not clear. It was sold in the 1950s by Harry Winston to a private collector, and was sold again at auction in 2010. The diamond is emerald cut with rounded corners, and is mounted on a platinum ring with two flanking shield-shaped diamonds. (Wikipedia)