A rare blue diamond that was expected to be the star attraction at Sotheby’s high jewellery auction in Geneva has failed to find a buyer, despite its extraordinary pedigree and multimillion-dollar valuation, Rapaport.com reported.
The cushion-shaped, 6.03-carat fancy vivid blue diamond, graded internally flawless and classified as a type IIb stone, was estimated to fetch up to CHF 9.6 million (about $12.3 million). Sourced from South Africa’s Cullinan mine, one of the world’s most famous diamond-producing sites, the gem was positioned as the headline lot of the sale. Yet when bidding closed on 12 May, the stone remained unsold.
Despite this surprise, the broader auction delivered strong results, with total sales reaching CHF 23.4 million ($29.9 million). Many lots exceeded expectations, reflecting continued robust demand for rare gemstones and high-end jewellery.
Among the standout performers was a Van Cleef & Arpels diamond bracelet, which sold for CHF 486,400, far above its CHF 95,000 estimate. Diamond pendant earrings also drew intense bidding, achieving CHF 217,600 against a modest upper estimate of CHF 30,000.
Other highlights came from prestigious maisons, including Bucherer, Cartier, Chopard, Bulgari, and Lacloche Frères, reinforcing the dominance of heritage luxury brands in the high-jewellery market.
At the top end of the sale, a pair of perfectly matched 18.38-carat D-colour flawless diamonds achieved CHF 2.5 million, in line with expectations. A striking Colombian emerald necklace fetched CHF 1.9 million, while “The Peacock of Ceylon”, a 102.40-carat sapphire, sold for CHF 1.5 million.
Bulgari also featured prominently, including a Serpenti wristwatch formerly owned by the wife of Italian entrepreneur Romeo Invernizzi, which sold for CHF 652,800. Meanwhile, a pair of rare Ceylon sapphire earrings brought in CHF 640,000, and a Lacloche Frères tassel necklace reached CHF 627,200.
Closing out the top lots were finely crafted ruby earrings by Boucheron, which sold for CHF 614,400.
