A 12.03-carat blue diamond could fetch a record US$55 million (S$78 million) when it goes under the hammer at Sotheby's auction house in Geneva on Wednesday.
The "fancy vivid blue diamond" Blue Moon, discovered in South Africa in January last year, is the largest cushion-shaped stone in that category to ever appear at auction.
Sotheby's put its estimated sale price between US$35-$55 million which, at the higher end, would mark an all-time record for the sale of a diamond at auction.
"Fancy vivid" is the highest category for coloured diamonds.
