Internally flawless, the cushion-cut, 11.15-carat, fancy vivid pink diamond will carry a presale estimate of $US21 million ($AU30.88 million).
"Pink diamonds are exceptionally rare in nature," Kristian Spofforth, Sotheby's head of jewellery, told Reuters.
"You then add in the extra factors like it being over 10 carats, internally flawless and Type IIA, and you get right down to the pinnacle.”
He added: "We saw over the lockdown crisis and the COVID crisis that there is always demand for the rare and the beautiful in the world, and this is something exceptionally rare that I think will have plenty of bidders on the day.”
The Williamson Pink Star originates from the Williamson Mine in Tanzania where it was discovered as a 32.32-carat rough by miner Petra Diamonds before being polished by Diacore.
“Driven by a limited supply and rising demand, prices for top-quality large pink diamonds over five carats have increased exponentially over the past decade,” said Wenhao Yu, chairman of jewellery and watches at Sotheby’s Asia.
The Williamson Star is the second largest diamond of that colour and clarity to feature at auction. The only diamond to exceed it is the 59-carat CTF Pink Star, which returned $US71.2 million ($AU104.7 million) at auction at Sotheby’s in 2017.
Ahead of the auction, the Williamson Pink Star will go on tour to Dubai, Singapore and Taipei before arriving in Hong Kong. The auction is scheduled for 5 October.
Yellow rough
A 151-carat yellow rough diamond will be the headline item at Mountain Province’s sale in Antwerp later this month.
The tender will feature 90 diamonds which have been discovered at the Gahcho Kué mine in Canada, including the aforementioned yellow octahedron which is described as having “exceptional clarity.”
Mountain Province holds a 49 per cent stake in the Gahcho Kué deposit, with De Beers owning the remainder.
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