The stunning 167.97-carat Mackay Emerald was mined in Muzo, Colombia. The largest cut emerald in the National Gem Collection, it is set in an Art Deco diamond and platinum necklace designed by Cartier Inc. In 1931, Clarence H. Mackay presented the necklace as a wedding gift to his wife, Anna Case, a prima donna of the New York Metropolitan Opera from 1909 to 1920. The piece was donated to the Smithsonian Institute by Mrs. Anna Case Mackay in 1984.
Source: The National Gem Collection by Jeffrey E. Post.