Olivia Wilde's vintage diamond and emerald engagement ring is still one of my all time favorite celebrity engagement rings. "All they know is that it went through Paris around 1921," Olivia told Brides. "I love imagining the story of this ring. Who had it? It's a bit of an aqua emerald, not a deep dark green. Jason (Sudeikis)said it reminded him of my eyes, which is very sweet."