Set into an asymmetric necklace designed by de GRISOGONO and offered on 14 November at Christie’s in Geneva, this 163.41 carat, flawless D-colour emerald-cut diamond is the largest ever to come to auction.
On 4 February 2016, a 404.20 carat rough diamond was mined in eastern Angola. It would turn out to be the 27th-largest rough white diamond ever discovered, and the largest ever found in Angola.
Early spectrographic testing at the Gemological Institute of America (GIA) in New York declared the stone to be a D-colour, Type IIA diamond — a variety highly valued for its transparency and colour.
The jewel that was extracted from it is one of the largest D-Flawless emerald-cut diamonds the GIA has ever seen, and the largest ever to be offered for sale at auction. ‘The extreme rarity of a diamond of this quality cannot be overstated,’ GIA researchers wrote in their monograph on the stone.
The original, 404.20 carat rough diamond that was mined in eastern Angola — the 27th largest rough white diamond ever discovered
From the GIA, the rough travelled to New York’s diamond district — specifically, an unprepossessing glass building on 5th Avenue and 47th Street that houses the offices of the Julius Klein Group. There, a team of more than 10 specialists transformed the 404.20 carat diamond — the largest they had ever worked with — into the final cut-and-polished gem.
Diamond expert Isaac Barhorin spent weeks examining the stone in different lights; measuring every groove and ridge, analysing its interior with a loupe and a binocular microscope, and feeling it with his fingers until he understood the stone thoroughly. ‘I start by seeing what the stone can give,’ Barhorin explains. ‘I am looking for cracks, grainy spots, feathers and carbon spots, and I will build the stone around these. The goal is to reach an internally flawless stone.’ Using a felt-tip pen, he marked where the first cuts should fall.
On 29 June 2016, after months of analysis, 80-year-old master diamond cleaver Ben Green was ready to go to work. A diamond cutter since 1964, Green is respected as the number-one cleaver in the world. ‘Diamond is like wood, it has a grain,’ he says. ‘You can saw it or divide it along the grain.’ Using the traditional low-tech tools of the diamond cleaver’s trade — dark cement to hold the diamond in place on the wooden stump, a loupe and two flat blades — Green split the stone cleanly in two.
Weeks of perfecting the cut on the polishing wheel followed. To create each facet, the stone is carefully angled by hand onto a rotating diamond-coated disc, guided by nothing but the naked eye, touch and decades of experience. Each turn of the disc hones each facet to ensure the maximum beauty of the gem. After more than six months, the final 163.41 carat emerald-cut form was revealed.
The 163.41 carat emerald-cut gem that was extracted from the rough diamond following months of detailed analysis
In December 2016, the diamond was brought to the Geneva headquarters of de GRISOGONO. Founder Fawaz Gruosi and his team of five master craftsmen and women were faced with a difficult task: how to transform this massive stone into a wearable piece of jewellery.
In the book Daring Creativity, which charts the history of the de GRISOGONO jewellers, historian Vivienne Becker describes Gruosi as ‘a reverent revolutionary with a deep, intuitive understanding of jewellery, a respect for the noble arts of the goldsmith and the jeweller, and an unfettered passion for gemstones.’ Even the smallest piece is ‘a work of art, full of movement, colour and details,’ Gruosi has said.
But despite his years of experience, having what he describes as ‘the most beautiful diamond in the world’ on his desk gave Gruosi ‘quite a big headache’, not least because he is extremely exacting. ‘I am crazy enough to break a jewel apart and start again if I am not happy with it,’ the jeweller insists.
‘I never thought I would work with a 163.41 carat diamond of this quality,’ Gruosi says. ‘I have never had a problem finding creative ideas, but this time there was the immense pressure of “dressing” such an amazing diamond. I couldn’t do something very simple or that has already been seen. I needed a design that is outside-the-box.’
The largest D flawless diamond ever offered at auction: a sensational diamond and emerald necklace, by de Grisogono. Further accompanied by hardbound monograph from the GIA Gemological Institute of America featuring additional photography, data collection charts and gemmological research, attesting to the rarity of this diamond. Estimate on request. This lot is offered in Magnificent Jewels on 14 November 2017 at Christie’s in Geneva
Working closely with Patrick Affolter, head of the house’s High Jewellery atelier, alongside the de GRISOGONO design team, Gruosi would hit upon an asymmetric design featuring 18 emerald-cut diamonds on one side, with the 163.41-carat diamond as the centrepiece.
‘It is almost two pieces of jewellery,’ reveals Grousi. ‘The “queen” or diamond is alone but surrounded by an haute couture dress.’ The design allows for the stone to be detached from the necklace and incorporated into other jewels.
Now, after being toured to Hong Kong, London, Dubai and New York, the 163.41 carat, flawless D-colour emerald-cut diamond will be offered in Christie’s Magnificent Jewels sale on 14 November in Geneva.
‘Over our 251-year history, Christie’s has had the privilege of handling the world’s rarest and most historic diamonds,’ says Rahul Kadakia, International Head of Christie’s Jewellery department. ‘This sensational gem propels de GRISOGONO into a class of its own.’