The second ring surfaced while Grace filmed High Society: Rainier reportedly bought a real jewel for the movie and for her to keep. Cartier’s records show a 10.48-carat emerald-cut diamond set in platinum, flanked by tapered baguettes. That ring has been called one of the most expensive celebrity engagement jewels, once listed at $4.06 million in 1956 and today valued at about $38.8 million.
Both rings passed to the House of Grimaldi after Grace’s death in 1982. The family loaned pieces, including both engagement rings, to Cartier’s Fifth Avenue mansion for a 2016 display; Cartier even dedicates a room to her. Today the jewels remain in the care of Monaco’s royal household.