What a looker! And Grace Kelly ain’t so bad either… This 12 ct. t.w. diamond ring had its close-up in 1956’s High Society and even prompted a line of dialogue. Glimpsing the stunner, Bing Crosby teasingly asks co-star Kelly, “Some stone. Did you mine it yourself?” The jewel was, in fact, Kelly’s own—her second engagement ring from Monaco’s Prince Rainier III. Initially, the royal proposed with a band of rubies and diamonds. Soon after, this more substantial Cartier rock—a 10.47 ct. emerald-cut diamond flanked by two baguettes set in platinum—took its place. The couple wed in April 1956, and the star and her stone left show business for good. After the princess’ death in 1982, the ring was bequeathed to the Princely House of Monaco. Last winter, it was shown to American museumgoers for the first time in the “Cartier and America” exhibition at the Legion of Honor in San Francisco. Of all the pieces on display, says Martin Chapman, curator of European Decorative Arts, “the engagement ring was the most beloved by our visitors.”