A 163.4 carat flawless white diamond, the largest ever to come to auction, expected to bring in a excess of $30 million, was previewed by Christie's in Hong Kong on Thursday.
Christie's European Chairman and world-wide head of its luxury division, Francois Curiel said he had never come across anything like it.
The 404.20-carat rough diamond was found in an Angolan mine in 2016, the largest ever to be found in the country according to Fawaz Gruosi, founder of de Grisogono, the jewelers that acquired the diamond.
The diamond, which can be detached from its white gold, diamond and emerald necklace, goes on the block in Geneva on November 14.