Sotheby’s New York auction leads with rare 10-carat blue diamond

The next jewelry look to trickle down from high auction rooms is modular, color-forward and built for movement. Sotheby’s High Jewelry sale in New York on June 16 will bring 119 lots to market, led by a 10.02-carat fancy intense blue diamond and a circa-1960s Harry Winston necklace that can shift from one long line to two bracelets.

The blue diamond is the kind of stone that sets the tone for what follows in color and silhouette. Sotheby’s describes it as an unmounted cut-cornered rectangular modified brilliant with VS2 clarity, and estimates it at more than $6 million. The house says it is only the third 10-carat-plus fancy intense blue diamond offered at auction since 2008, a reminder of how rarely a stone of this size and saturation comes loose onto the market. The buyer will also be offered a custom setting through Sotheby’s Bespoke, a detail that pushes the piece from specimen into personal jewel, and one that could influence the next wave of smaller blue-stone designs for everyday wear.

The most compelling design lesson may come from the Harry Winston piece. Estimated at $800,000 to $1.2 million, the necklace-bracelet combination is composed of graduated pairs of round diamonds alternating with marquise-shaped diamond clusters. It measures about 15½ inches and detaches into four sections, allowing it to be worn as two bracelets or as a necklace of varying length. That flexibility is exactly the kind of archival idea that tends to resurface in more accessible jewelry: a collar that can be shortened, a bracelet that converts, or a statement necklace that does not stay fixed in one form.

Sotheby’s is leaning hard into that mix of rarity and wearability. Highlights will be on view in Singapore, Hong Kong, Taipei, Geneva and Los Angeles before the New York sale, and the roster also includes names such as Van Cleef & Arpels, Cartier and Reza. The emphasis on branded, provenance-rich jewels shows where collector appetite is strongest: not only in carat weight, but in identity, documentation and recognizable design language.

That demand has been reinforced by recent results. Sotheby’s December 9, 2025 High Jewelry sale in New York brought in $30.1 million and sold 94% of the lots. Quig Bruning said the response showed demand remained "deep and robust," and that momentum helps explain why this June sale is built around colored diamonds, historic signatures and pieces whose shapes can travel far beyond the auction floor.