The current world record holding colourless diamond demanded $260,000 per carat, but this rare 'flawless' stone found in Botswana is expected to push north of $320,000 per carat when it is sold privately.

By Joe McDonough

Posted on February 9, 2018

A flawless round ‘brilliant’ cut white diamond, about the size of a large strawberry, is expected to break the world record as the most expensive ever sold per carat.

Up for private sale at London’s auction house Sotheby’s this month, the stone weighing slightly more than 102 carats, is expected to demand well over $US33 million or more than $320,000 per carat.

And while it is not as sizeable as the 163-carat oval stone which attracted a world record price for a colourless diamond in Hong Kong in 2013, it’s rarity and perfect condition should combine to easily surpass the $260,000 per carat history-making price tag.

Sotheby’s, which handled the Hong Kong sale as well, says the Botswana-mined diamond is the only gem over 100 carats to have been given the highest grades in every criteria by the Gemological Institute of America, which judges the quality of the precious stone’s carats, colour, clarity and cut.

Patti Wong, founder and chairman of Sotheby’s Diamonds, called the crystal-clear stone “over 100 carats of flawless perfection”. It went on display in the London showroom yesterday.

The diamond was cut from a 425-carat rough mined by the De Beers group in Botswana. The cutting process took over six months and required the diamond to be transported between Johannesburg and New York.

Wong said the diamond cutter “approached the task with the precision of Michelangelo”.

Sotheby’s also holds the record for the most expensive diamond ever, having sold the 59.6-carat Pink Star for $71 million to Hong Kong-based jewellery retailer Chow Tai Fook last year.