Bulgari Laguna blue diamond could fetch $28m in auction 

A rare 11.16 carats fancy vivid blue diamond could fetch between 22 to 25 million Swiss francs ($24 to $28 million) when it goes under Sotheby’s hammer next week in Geneva.

Named the Bulgari Laguna Blu, the pear-shape cut diamond boasts a rich blue hue that the auction house qualifies as “extraordinary” and “mesmerizing”.

It is the highest grade blue diamond ever graded by the Gemological Institute of America (GIA) and the third-largest pear-shaped fancy vivid blue diamond to ever go for sale on an auction, according to Olivier Wagner, head of jewellery at Sotheby’s Geneva.

The gem, first exhibited at the famous Met Gala fashion show in New York on Monday, is expected to attract the interest from global collectors

Recent world records set by Sotheby’s in Geneva include the “Blue Moon of Josephine”, which was sold for $48.5 million in November 2015, making it a world auction record for any diamond at the time, and to this day the record price per carat at over $4 million per carat.

Another iconic diamond sold in Geneva is the “Graff Pink”, which fetched $46.2 million in 2010 – the world record for any pink diamond at the location, only second to the “Pink Star” — the largest internally flawless pink diamond that the GIA has ever graded.

GIA diamonds are graded for the intensity of their colour and only those with the strongest saturation are determined to be “vivid” in colour. 

For blue diamonds this label is so rare that of all the blue rocks submitted to the GIA, less than 1% are found to be “vivid” in colour, according to Sotheby’s.

“Even rarer is to find a coloured diamond which does not have a secondary colour present, they may often have a tint of another colour,” the auction house said.

The Bulgari Laguna Blu is a rarity three times over, as it is a blue diamond, a jewel signed by Bulgari, and an unseen and unmodified gemstone.

The diamond was initially mounted as a ring by Bulgari for a special commission by the original owner. It was sold in 1970 and it’s now part of a necklace.

Last April, Sotheby’s Hong Kong sold the fancy-vivid-blue 15.1 carats “De Beers Cullinan Blue” for $57.5 million, sharing a record with the 14.6-carat “Oppenheimer Blue” sold at Christie’s Geneva in 2016.