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Flawless Blue Diamond Sells at Auction

A flawless blue diamond weighing 13.22 carats sold at Christie's auctioneers on Wednesday 14 May for a record breaking £14 million. Jean-Marc Lunel, senior international specialist of Christie's jewellery department described the stone as, 'absolutely perfect, absolutely pure externally and internally. It is almost a dream'.

South African blues

Most probably mined in South Africa, blue diamonds of this size and purity are exceptionally rare. In the past decade in fact, only three similar blue diamonds of 10 carats or more have been sold at auction. The colour in blue diamonds is due to the presence of tiny amounts of the chemical boron.


Boron bonds with the carbon that makes up pure diamond but leaves some carbon atoms with an unused electron not used in the bonding process. This spare electron absorbs red light and makes the diamond appear blue when viewed in white light. Only a few boron atoms are needed per million carbon atoms to make this happen!

If you have any blue diamonds that you would like to sell, please contact Simon Rufus, gemmologist at Grand Auctions, Folkestone, Kent.