The fitted case for this necklace is stamped "Ch. Fontana & Cie, Palais Royal 96 98 Paris". This is very helpful in the dating of the piece as we know from Volume III of Henri Vever's "La Bijouterie Franaise au XIX Sicle" that the firm with the above mentioned name only existed from 1871-1881. Prior to that, the company, which had been founded and run by Charles' father Thomas, was called T. Fontana et Cie. Afterwards, in 1882, Charles' cousin founded Fontana Frres. The consecutive firms of Fontana were amongst the most celebrated French jewellers of the late 19th Century. This necklace, with its rather complicated knife-edge work, is typical of the period.