An Art Nouveau Alexandrite, Diamond and Enamel Brooch, by Marcus & Co. Photo Christie's Image Ltd 2014

Designed as a green enamel plaque with sculpted gold detail, centering upon a cushion-cut alexandrite, weighing approximately 8.41 carats, enhanced with bezel-set old European-cut diamonds, suspending a green enamel bead, mounted in rose gold, circa 1900. Signed M & Co. for Marcus & Co. Estimate $70,000 – $100,000

With report CS 54809 dated 1 May 2013 from the American Gemological Laboratories stating that it is the opinion of the Laboratory that the origin of this material would be classified as Classic Ceylon (Sri Lanka). Heat enhancement, none

Christie's. MAGNIFICENT JEWELS, 16 April 2014, New York, Rockefeller Plaza - www.christies.com