An Art Deco 'Ying-Yang pendant, by Cartier Paris, circa 1919. Platinum, gold: round old-, single- and rose-cut diamonds: two drilled emerald beads: calibré-cut rubies and collet-set cabochon rubies; one emerald, four rubies and four buff-top onyxes on the loop; onyx; black enamel on the clasp. Image source: Cartier, by Hans Nadelhoffer
Mackay emerald, 168 karats, 1931. - 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
Emerald and diamond necklace - Designed by Ostertag; set with carved emeralds and diamonds in platinum; circa 1930. The longest dangle on the necklace and the earrings are each about 3 1/2 inches long. Photograph by Tino Hammid.