A natural pearl and multi-gem necklace, by Bvlgari. Photo Christie's Image Ltd 2013

Designed as a graduated series of fifty-three natural pearls, measuring from approximately 5.35 to 11.90 mm, spaced by an alternating series of ruby and emerald beads, to the rectangular-cut diamond bar clasp, mounted in platinum, 22 ins. Signed BVLGARI. Estimate $50,000 – $70,000

With report 66728 dated 19 February 2013 from the SSEF Swiss Gemmological Institute stating that the analysed properties confirm the authenticity of these saltwater natural pearls 

Christie's. NEW YORK MAGNIFICENT JEWELS AND THE PRINCIE DIAMOND. 16 April 2013. New York, Rockefeller Plaza.