This is the rarest white diamond ever to come on to the market. It is the only known round brilliant-cut diamond over 100 carats that is perfect in every way. Apart for its high number of carats, its colour, clarity and cut are sheer perfection.

In celebration of the first anniversary of its New Bond Street salon in London, Sotheby’s Diamonds, a retail boutique specialising in the world’s finest diamonds, has unveiled this exceptional stone. At 102.34 carats, this masterpiece of nature is the largest, round, D colour, flawless diamond known to man.

The only stone of its kind ever graded by the Gemological Institute of America, the diamond has achieved the highest rankings under each of the criteria by which the quality of a stone is judged. The diamond is D colour (the highest grade for a white diamond); of exceptional clarity (being completely flawless, both internally and externally), and has excellent cut, polish and symmetry. As with the famous Cullinan I and Koh-i-noor diamonds, which are part of the British Crown Jewels, the stone is part of the rare subgroup comprising less than two per cent of all gem diamonds.

Patti Wong, founder and chairman of Sotheby’s Diamonds, said, “In the course of my long career, which has brought me close to some of the greatest stones the earth has ever yielded, I have not encountered anything quite like this. With its outstanding weight, perfect colour, clarity and cut, it is a masterpiece of nature brought to life by human hand, blazing with a brilliant firework-like display of almost every colour on the spectrum – mesmerising to behold.”

Another exquisite colourless diamond was sold at auction for $30.6m by Sotheby’s Hong Kong in 2013 and this diamond is expected to sell for considerably more.

Sothebys.com