The rough stone, the largest ever discovered in the African country, originally weighed 404 carats and measured over 7 centimetres in length.
At the event, a 163-carat diamond - the largest of its kind - has been sold at a whopping price of $33.7 million! Experts, however, are bitterly disappointed as they had expected the diamond to be sold for at least £12 million more. Ten diamond-cutting specialists worked on the rough in NY after it was analysed in Antwerp.
The diamond, the centrepiece of an asymmetric gem-studded necklace designed by Fawaz Gruosi, founder of Geneva jeweller De Grisogono, exceeded the auction house's expectation of US$25 million.
Mounted in a diamond and emerald necklace, the white, matchbox-size rock from Swiss jeweler de Grisogono was acquired by an unidentified buyer.
Sotheby's holds the record for the most expensive diamond ever auctioned, having sold the 59.6-carat Pink Star for $71m to Hong Kong-based jewellery retailer Chow Tai Fook.
The"Le Grand Mazarin, a 19.07-carat light pink diamond was once set in the crown of Napolean
"It took over 1,700 hours to create this unique jewel and involved a team of 14 craftsmen", Christie's said.
Diamond cleaver Ben Green analysed the gem for months and eventually started working on splitting the rough diamond in two in June a year ago.
Another highlight of Tuesday's auction is the "Le Grand Mazarin", a 19.07-carat light pink diamond, which was once set in the crowns of numerous French kings and emperors, including Napolean.
The gem was named after Cardinal Mazarin, an Italian cardinal and diplomat, as well as a great art collector, who served as a chief minister under Louis XIII and Louis XIV, and who bequeathed it and other diamonds to the Sun King in his will. He also said that it also gave him a big headache as there was an huge pressure of "dressing" such an wonderful diamond and doing something out of the box, as reported by Sky News.