11.28-carat Infinite Blue diamond sells for US$25.4 million at Sotheby's Hong Kong

On the occasion of Sotheby's 50th anniversary in Asia, Sotheby's Hong Kong presented its crown jewel, The Infinite Blue, in a dedicated single-lot auction amidst a series of five evening sales on 5 October. 

The auctioneer opened the bidding on the 11.28-carat Fancy Vivid Blue diamond ring at HK$140 million. Eventually, it was hammered at HK$170 million, selling for HK$198 million (US$25.4 million) with fees to a lady in the saleroom with paddle number 8800. 

The jewel became the second lot that swept past the HK$100 million mark this season, following the HK$273 million Amedeo Modigliani’s portrait of Paulette Jourdain.

Lot 8001 | The Infinite Blue | A Fancy Vivid Blue diamond and diamond ring 
Set with a radiant-cut fancy vivid blue diamond weighing 11.28 carats, embellished with brilliant-cut and trapeze-shaped diamonds and brilliant-cut diamonds of pink tint, mounted in 18 karat white and pink gold
Clarity: VS2
Estimate: HK$208,000,000 - 288,000,000 (US$26.6 - 36 million) 
Hammer Price: HK$170,000,000
Sold: HK$198,220,000 (US$25.4 million)

Auction House: Sotheby's Hong Kong
Sale: The Infinite Blue

Date and Time: 5 October | 8:00 p.m. (Hong Kong Local Time)

Blue diamonds are among the rarest of all coloured diamonds. Of all natural diamonds, less than 0.02% come in blue. 

While other coloured diamonds can be found in mines worldwide, the sources for blue diamonds are incredibly limited, with the majority being unearthed in the Cullinan Mine in South Africa. But even there, such finds are extremely rare – only 0.1% of the total mining production can produce blue diamonds, irrespective of the strength of colour. 

The Infinite Blue, the aforementioned De Beers Blue, the current auction record holder for blue diamond The Oppenheimer Blue, and the per-carat record The Blue Moon of Josephine, were all from the Cullinan Mine. 

Apart from blue diamonds, the mine has also yielded many of the world's most famous diamonds, including the 530-carat Great Star of Africa, the largest faceted colourless diamond in the world. 

The Cullinan Mine in South Africa

The De Beers Blue, 15.1 carats | Fancy Vivid Blue diamond | Step-cut, Internally Flawless | Sold: HK$450,925,000 (US$57.5 million), Sotheby's Hong Kong, 2022

The Oppenheimer Blue, 14.6 carats | Fancy Vivid Blue diamond | Step-cut, VVS1 Clarity | Sold: CHF 56.8 million (US$57.5 million), Christie’s Geneva, 2016

The Blue Moon of Josephine, 12.03 carats | Fancy Vivid Blue diamond | Cushion-shaped, Internally Flawless | Sold: US$48.5 million, Sotheby's New York, 2015

The sale details of the mentioned blue diamonds:

  • The De Beers Blue, 15.10 carats | Sold: HK$451 million (US$57.5 million), Sotheby's Hong Kong, 2022
  • The Oppenheimer Blue, 14.62 carats | Sold: CHF 56.8 million (US$57.5 million), Christie's Geneva, 2016
  • The Blue Moon of Josephine, 12.03 carats | Sold: US$48.5 million, Sotheby's New York, 2015

Weighing 11.28 carats, The Infinite Blue has been graded Fancy Vivid by the Gemological Institute of America (GIA) – the highest possible colour grading, awarded to no more than 1% of the blue diamonds submitted to the GIA. 

In terms of clarity, it is classified as VS2, ranking sixth on the GIA scale, meaning minor inclusions are visible under 10x magnification by a skilled grader.

To enhance its appearance, the stone has been cushioned into a radiant cut, a style that combines the dazzling sparkle of a round brilliant and the aristocratic elegance of an emerald cut. With 70 facets, it creates a mesmerizing interplay of light while camouflaging minor imperfections.