Cartier-crafted Aga Khan emerald and diamond brooch sets a $9 million record as the world’s most expensive green stone

Cartier crafted it, Van Cleef & Arpels acquired it, and Harry Winston transformed it. This object of fascination is none other than the world’s most expensive green stone, a stunning 37-carat emerald set in a Cartier diamond and emerald brooch that was auctioned at Christie’s Geneva on November 12. This rare square-cut emerald, once owned by Prince Sadruddin Aga Khan, achieved unparalleled beauty when Cartier encased it in a brooch adorned with 20 marquise-cut diamonds for his wife, Nina Dyer, a former model who adopted the title Princess Nina Aga Khan. With her new name came an array of extravagant gifts, including luxury sports cars and exquisite jewels, among which this breathtaking Cartier brooch stood out.