The 18.4-carat “Rockefeller Emerald” set a new world auction record for the highest per-carat price ever achieved for an emerald when it fetched $5.5 million yesterday at Christie's New York, which is headquartered, quite fittingly, in Rockefeller Center. Described by Christie's as possessing mesmerizing color and impeccable clarity, the Colombian emerald was originally purchased in […]