Founder Fawaz Gruosi described the gem as "the most lovely diamond in the world". And this was validated at the Christie's event in Geneva.
Called The Art of Grisogono, the 163.41-carat diamond - attached to an emerald and diamond necklace - was sold to an unnamed telephone bidder at the Christie's autumn jewel auction in Geneva, Switzerland.
"It took over 1,700 hours to create this unique jewel and involved a team of 14 craftsmen", Christie's said. The dazzling necklace is made of 18 diamonds on one side and a dual row of pear-shaped emeralds on the other.
The buyer's identity has not been revealed.
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The largest ever diamond of its kind to come to auction has been sold in Geneva for £25.5m.
The diamond itself was cut from a 404 carat rough rock which was found in February of 2016 in Angloa's Lulo mines.
The stone up for sale Tuesday is meanwhile a "much larger diamond, and its title of the largest ideal stone could see it attract a winning bid of over $50 million", he suggested.
The colourless diamond was then analysed for many months by diamond cleaver Ben Green.
A team of more than 10 specialists from the Julius Klein Group in NY transformed the rough diamond into the final cut and polished gem. The finished piece of jewellery comprises white gold, diamond and emeralds and has been designed by Swiss jewellery maker de Grisogono.
Set in an emerald and diamond necklace, the massive gem had been on tour to Hong Kong, London, Dubai and NY.
However, he said it gave him "quite a big headache".