An opulent piece of jewellery featuring the substantial Queen of Holland diamond as its centrepiece, the Toussaint necklace was commissioned in 1931 by Ranjitsinhji Jadeja (r. 1907–33), the ruler of the former princely state of Nawanagar (present-day Jamnagar, Gujarat in India). The necklace was designed by the luxury jewellery house Cartier and named after its influential director Jeanne Touissant, who absorbed influences from Mughal and other royal Indian jewellery in her work, and is also known for her involvement in the Art Deco movement. Following its dismantling in 1960, the necklace no longer exists in its original form.

The two chains of the Touissant necklace consisted of large clear white diamonds, with square pink ones acting as links. At its centre, there were three pink diamonds, along with a 26-carat blue and a 12-carat green diamond. Its central pendant stone was the bluish Queen of Holland, then weighing 136.25 carats and considered one of the largest diamonds in the world. 

Information on the diamond’s origins is entirely speculative. Its appearance in Amsterdam, Netherlands, recorded in 1904, would indicate South African origin given the large number of diamonds making their way into the country from South Africa at the time. Yet its bluish tint, characteristic of Golconda diamonds, has led experts to suggest that it originated in the Deccan region of India. Named after the then ruler of the Netherlands, Queen Wilhemina (r. 1890–1948), the diamond was cushion-cut in the early twentieth century by Dutch firm F. Friedman & Co., who owned it at the time. Ranjitsinhji, a jewel connoisseur as well as renowned cricketer, bought it from the firm in 1930, and took it to Cartier in 1931 to have it set as the centrepiece of what would become the Touissant necklace. 

The necklace was completed in 1933, the year of Ranjitsinhji’s death. It went on to make several public appearances around the neck of his nephew and successor Digvijaysinhji Jadeja (r. 1933–66). The Touissant necklace remained with the family until it was dismantled in 1960, when Cartier bought the Queen of Holland as a standalone. After it was sold to William Goldberg in 1978, the diamond was further cut down to 135.92 carats. At the time of the writing, the diamond is owned by Robert Mouawad, former president of the Mouawad house.

The Toussaint necklace entered popular consciousness again following the release of the American film Ocean’s 8 in 2018. The comedy heist film featured a smaller imitation that was recreated by Cartier using zirconium oxide crystals in place of the original diamonds.