The Attallah Cross which Diana, Princess of Wales, famously paired with an Elizabethan-style Catherine Walker gown for a London charity gala in 1987 is expected to fetch up to £120,000 at auction.
The Garrard crucifix pendant – embossed with gold, silver, amethyst and diamonds – will lead Sotheby’s annual Royal and Noble sale which begins on January 6 and ends on January 18.
Diana wore the pendant to a charity ball in London on October 27, 1987, in aid of Birthrights, a charity working to protect human rights during pregnancy and childbirth, of which she became patron in 1984.
The piece reflected her lifelong relationship with Garrard, which adapted The Spencer Tiara for her wedding day and from whom she selected her sapphire engagement ring in 1981.
In her last public appearance, Diana wore a diamond and South Sea pearl piece by Garrard which became known as the Swan Lake necklace.
The Attallah Cross pendant was owned by the former group chief executive of Asprey and Garrard, the late Naim Attallah, who would often lend it to Diana to wear at events.
It was later passed on to his son Ramsay Attallah, who said: “Princess Diana and my father were friends and I remember that she often came to see him at the historic Garrard store on Regent Street, where his office was, and she would ask to borrow the pendant on several occasions. She really loved the piece.”
The necklace is understood to only have been worn by Diana and, after her death, it was never seen in public again, the auction house said.
Kristian Spofforth, Head of Jewellery at Sotheby’s London, said: “Jewellery owned or worn by the late Princess Diana very rarely comes on to the market, especially a piece such as the Attallah cross, which is so colourful, bold and distinctive.
“To some extent, this unusual pendant is symbolic of the princess’s growing self-assurance in her sartorial and jewellery choices at that particular moment in her life.
“We are confident that this unique 1920s piece of jewellery by Garrard, with such an exceptional provenance and only ever worn by the princess herself, will attract the attention of a wide variety of bidders, including royal and noble jewellery collectors, as well as fans of the princess keen to share part of her history.”
