In the Spartan days of World War II, American women went without diamonds. Even after the armistice, ladies wore jewels only when going out on the town. But Harry Winston had a different vision. In 1946, he fashioned 219 diamonds (26.18 cts. t.w.) into this giant Maltese cross brooch. The next year, Carol Channing was singing “Diamonds Are a Girl’s Best Friend” on Broadway, and in Paris, Christian Dior debuted his New Look of ladylike, cinched-waist suits—all of which cried out for sparkly jewelry. “We were coming out of a dry spell,” says Joyce Jonas, president emeritus of the American Society of Jewelry Historians, “and Harry Winston was ahead of everybody. By 1947, women were finally back in wonderful feminine suits. By the early 1950s, they were wearing diamonds in the daytime.” When the brooch—then 10 years old—made the cover of Vogue’s Feb. 1, 1956, edition, i