
Actress-turned-princess Grace Kelly was given a Cartier engagement ring by Prince Rainier III of Monaco in 1956, a jewel that went on to become one of the most iconic in history.
Cartier described the 10.47‑carat emerald‑cut diamond set in platinum with tapered baguette sides as "truly … an exceptional diamond," and Jewelrybox reported it is now valued at $39 million.