One of the season's most glamorous jewels is coming to market. Christie's will offer a Bulgari ring set with a 24-karat Fancy Intense Pink diamond at its Magnificent Jewels sale during Autumn Luxury Week in Geneva on November 10, with an estimate of $12 million to $18 million. The stone has a storied path to the saleroom. It was acquired in India by the current owner's great-grandfather and given to Bulgari to be set in the 1950s, when Rome — the house's home since its founding — was the center of postwar glamour, its Cinecittà studios drawing Hollywood stars in what became known as Hollywood on the Tiber. A distinguished European noble family then held the ring for more than seven decades. The house leans on the ring's cinematic backstory. When the stone was set in the 1950s, Bulgari's boutique on Rome's Via Condotti was a meeting point for stars filming at Cinecittà — Elizabeth Taylor and Richard Burton, Audrey Hepburn and Mel Ferrer among them. The jeweler presents the ring as an artifact of that postwar glamour as much as a gemstone. The diamond is classified Type IIa, a distinction held by fewer than two percent of the world's diamonds, and its hue earned the coveted Fancy Pink color grade. Pink diamonds get their color from a rare distortion of the crystal lattice caused by intense pressure deep in the earth, which alters how light passes through the stone. High jewelry with this kind of provenance rarely surfaces, and the Geneva sale will test whether collectors still chase trophy stones at the very top of the market.