There’s a reason they call it emerald cut—the classic shape most ably showcases the shine of the iconic green gemstone. That’s part of what makes these perfectly circular Harry Winston clip earrings—which sold for $218,500, nearly double their high estimate at Sotheby’s Sept. 20 Important Jewels sale in New York City—so rarified. “You almost never see emeralds cut in a round shape,” says Robin Wright, vice president and specialist in Sotheby’s New York jewelry department. “You have to have a really good stone, and these are very good Colombian emeralds. They are so bright and so richly colored.” The emeralds were faintly treated with Canadian balsam oil, suggesting that their vivid green hue is almost 100 percent natural. The provenance of the Harry Winston–designed circa-1979 earrings also played into their elevated sale price. So when it came time to sell these