An alexandrite and diamond ring. Photo: Christie's Images Ltd 2013

Set with a cushion-cut alexandrite, weighing approximately 18.23 carats, flanked on either side by a triangular-cut diamond, mounted in platinum. Estimate:  $400,000 – $600,000

With report CS 55020 dated 24 May 2013 from the American Gemological Laboratories stating that it is the opinion of the Laboratory that the origin of the alexandrite would be classified as Classic Ceylon (Sri Lanka). Standard Enhancement: None

Accompanied by a supplemental letter from the American Gemological Laboratories attesting to the rarity and prestige of this alexandrite. 

Christie's. MAGNIFICENT JEWELS. 15 October 2013. New York, Rockefeller Plaza.