Lush blue diamond up for auction.Known as the Premier Blue, this 7.59 carat fancy vivid blue interna

Lush blue diamond up for auction.Known as the Premier Blue, this 7.59 carat fancy vivid blue internally flawless round brilliant was sold in 2013 at Auction and may have brought in  as much as $2.5 million a carat at Sotheby’s Hong Kong. It was the largest brilliant cut diamond of that colour ever graded at the Gemological Institute of America gem testing laboratory. Coloured diamonds have been rising steadily in price, due to their rarity, designer appeal and potential investment. The stone is currently travelling the world for previews. Two things make this stone special. Coloured diamonds are rarely internally flawless. With the rough is so rare and expensive, all of it is used for gems, regardless of clarity, unlike with the more common white to yellow or brown stones. Rounds are also rare, since they tend to waste more rough when cut (a rough diamond will lose between 40 and 60% of its weight in cutting, depending n the stone). Fancy shapes are more common, typically selected to maximise the use of the crystal using a CAD programme such as SARIN. LozImage credit: Sothebys. -- source link

More pics about