Fancy vivid blue diamonds of more than 10 carats are among the rarest gems in the world and Sotheby’s is set to offer one in its Geneva High Jewelry sale on May 13.
“The Mediterranean Blue” is 10.3-carat fancy vivid blue diamond (the highest grade for a blue diamond) with a VS2 clarity grade, according to the Gemological Institute of America (GIA). It is also a Type IIb diamond, a classification which represents less than 0.5% of all diamonds, according to the auction house.
The cushion-shaped modified brilliant gem will be a highlight of the auction with an estimate of about $20 million.
“Any vivid blue diamond is a discovery worth celebrating, but one as entrancing as this, particularly being over 10 carats, is a newsworthy event,” said Quig Bruning, Sotheby’s head of Jewelry, Americas & EMEA. “The Mediterranean Blue’s remarkable size, charming cushion-cut and ocean-blue color places it in the rarefied company of some of the most important blue diamonds to come to market in recent years.”
The Mediterranean Blue will be unveiled on April 8 at the Bassam Freiha Art Foundation in Abu Dhabi, a dune-shaped structure that Sotheby’s calls an “architectural marvel.” It’s a non-profit institution established by philanthropist and art collector, HE Bassam Said Freiha, who has collected works from the Orientalist art movement for more than 50 years. It is located on Saadiyat Island, which is also home the Le Louvre and the Guggenheim. It’s Sotheby’s first public exhibition in Abu Dhabi since 2009. The auction house teased that more details about the unveiling will be announced in the coming weeks.
The Mediterranean Blue is the result of a 31.94-carat rough diamond discovered in the Cullinan mine in South Africa in 2023, Sotheby’s said. The creation of the cut-and-polished diamond was the result of a year of study followed by a planning and cutting process that took six months, Sotheby’s said.
Blue diamonds of exceptional weight and high quality are among some of the most valuable gems and jewels sold at auction over the past 10 years. In fact, two blue diamonds are among the three diamonds ever sold at auction, by value.
Most are sourced by the Cullinan mine, which has yielded many of the world’s most famous diamonds, including the 530-carat Great Star of Africa, the largest faceted colorless diamond in the world.
Other extraordinary blues from the Cullinan mine include “The Blue Moon of Josephine”—a 12.03 carat cushion-shaped internally flawless fancy vivid blue diamond that sold for $48.5 million (more than $4 million per carat) at Sotheby’s Geneva in 2015, and more recently “The De Beers Blue,” a 15.10 step-cut fancy vivid blue diamond, which sold for $57.5 million in 2022 at Sotheby’s Hong Kong.
“The De Beers Millennium Blue” diamond, a 10.10 carat, oval-shaped, internally flawless gem and was sold at Sotheby’s Hong Kong in April 2016 for $31.8 million.
The 14.62-carat “Oppenheimer Blue,” holds the world auction record for a fancy vivid blue diamond of $57.5 million. It was sold by Christie’s in the May 2016 auction in Hong Kong.
“Only 0.3% of diamonds display a color that would be described as predominately blue among all diamonds submitted to GIA annually and of those, only a small number are fancy vivid weighing 10 carats or more,” the GIA said in Sotheby’s announcement. “The attributes of the Mediterranean Blue, weighing 10.03 carats in the most coveted fancy-color range, are absolutely exemplary for a diamond.”