An exceptionally rare 19-carat pink diamond goes under the hammer in Geneva on Tuesday, when it could fetch $50 million (Dh183.6m), setting a record for a stone of its kind.
The Pink Legacy used to belong to the Oppenheimer family, which for decades ran the De Beers diamond mining company, but auction house Christie's refused to say who the current owner was.
Christie's international head of jewellery, Rahul Kadakia, described The Pink Legacy as "one of the world's greatest diamonds".
The rectangular-cut diamond has been graded "fancy vivid" — the highest possible grade of colour intensity.
Christie's has noted that in the salesroom, fancy vivid pink diamonds over 10 carats are "virtually unheard of" and that only four vivid pink diamonds or over 10 carats have ever been offered at auction.
One of them, the nearly 15-carat Pink Promise, was sold last November at a Christie's auction in Hong Kong for $32.5 million. That amounts to $2.176 million per carat, which remains the world auction record price per carat for any pink diamond.
Record price possible
Eddie LeVian, CEO of jewellers Le Vian, said that record could fall at Tuesday's auction, which is being held at the ultra-luxurious Four Seasons des Bergues hotel on the banks of Lake Geneva.
"We've recently witnessed a meteoric rise in the number of the world's ultra-high net worth individuals who view rare, natural fancy colour diamonds as investments," Le Vian said in a statement.
"I therefore believe the Pink Legacy will beat the current world auction record," he added.
The stone was discovered in a South African mine around a century ago and was probably cut in the 1920 and has not been altered since, Christie's said.
"Imagine a domino that you have cut the corners off of," Jean-Marc Lunel, an international jewellery specialist at Christie's, recently told AFP, pointing out that the cut is a "classical so-called emerald cut", which stands out from the typical, more rounded, multi-faceted cuts used today.
The classic rectangular cut is traditionally used for white stones, but is rare for pink diamonds.
Christie's said the Pink Legacy is "the largest and finest Fancy Vivid Pink diamond ever offered at auction by the company," calling the stone "incomparable."
"It is probably the most beautiful (specimen) ever presented at public auction," Lunel said.