The cushion modified brilliant-cut diamond had been estimated at $20 million. Mined in 2023 from South Africa’s famed Cullinan mine, the gem was originally part of a 31.94-carat rough stone. According to Sotheby’s, the rough diamond underwent a year of intensive study followed by six months of meticulous cutting and polishing to bring the final masterpiece to life.

Before arriving in Geneva, The Mediterranean Blue embarked on a global tour beginning in Abu Dhabi, where it was unveiled at Sotheby’s inaugural exhibition in the region. The stone was presented alongside seven other high-value diamonds and gemstones valued collectively at over $100 million. Its tour included stops across the Middle East, Asia, and the United States, drawing attention from top collectors around the world.

“It is undoubtedly the defining stone of the season and ranks among the top blue diamonds we have sold,” said Quig Bruning, Sotheby’s Head of Jewelry, Americas & EMEA. “To witness the excitement it has generated throughout its global exhibition tour, culminating in today’s result, clearly reflects the growing global appetite for rare and impeccable diamonds, and a marked flight to quality among collectors.”

The sale of The Mediterranean Blue was the marquee moment of Sotheby’s High Jewelry auction, held at the Mandarin Oriental in Geneva. The event featured 93 lots and achieved a total of 42 million Swiss francs (approximately $50 million), with a 99% sell-through rate by value and 97% by lot count.