An antique sapphire and diamond necklace, by Biedermann. Photo Christie's Image Ltd 2013. 

Designed as a graduated series of ten cushion-cut sapphire plaques, each with a pendant hook for suspension, set with rose-cut diamonds, within an old mine-cut diamond surround, spaced by detachable old-mine cut diamond links, mounted in silver-topped gold, circa 1850, 8½ ins. (plaques detach and may be worn as a bracelet). Signed Biedermann. Estimate: $400,000 – $600,000

With report CS 57304 dated 8 October 2013 from the American Gemological Laboratories stating that it is the opinion of the Laboratory that the origin of these sapphires would be classified as Ceylon (Sri Lanka). No gemological evidence of heat. 

Christie's. MAGNIFICENT JEWELS. 10 December 2013. New York, Rockefeller Plaza -www.christies.com