10. Diamond Pendant
Donn by: Margaret Elphinstone, Hon.
Belonging to: Unknown
Value Estimate: $25,000–$50,000*
The Hon. Margaret Elphinstone is one of Queen Elizabeth II’s thirty-one first cousins. Being Princess Margaret’s and the Queen’s childhood friend, Elphinstone is frequently referred to as Queen Elizabeth II’s best friend. The Queen Mother even referred to Margaret as her “third daughter” during their shared summers in Balmoral.

©Max Mumby/Indigo/Getty Images Diamond Brooch
Margaret resided in Windsor Castle and Buckingham Palace during World War II while preparing to work as an M16 secretary. Elphinstone was a bridesmaid for Princess Elizabeth and Prince Philip’s 1947 wedding. She is clearly a jewelry enthusiast, as evidenced by the enormous diamond brooch she is wearing with her button-up coat.
