Commissioned by Queen Mary, the tiara channels Art Deco stylings and may be worth $5 million. Princess Margaret, left, wearing Queen Mary’s Diamond Lozenge Bandeau, right, ...

The 10-year-old princess appeared to be wearing a diamond horseshoe brooch—one she first wore to Queen Elizabeth's funeral that has been in the royal family for generations.

Princess Charlotte attends Queen Elizabeth's funeral on Sept. 19, 2022. Karwai Tang/WireImage. Queen Camilla isn't the only member of the royal family to memorably wear a horseshoe-shaped brooch.