A three-strand natural pearl, cultured pearl and diamond necklace. Photo: Christie's Images Ltd 2013.

The first strand comprising sixty-seven natural pearls; the second strand comprising sixty-one natural pearls and one cultured pearl; and the third strand comprising fifty-nine natural pearls and one cultured pearl, all measuring from approximately 10.90 to 4.70 mm, joined by a circular and baguette-cut diamond clasp, mounted in platinum, 18¼ ins. Estimate:  $200,000 – $300,000

With report 69409 dated 21 August 2013 from the SSEF Swiss Gemmological Institute stating that the analysed properties confirm the authenticity of these 187 saltwater natural pearls and the identity of these two beaded saltwater cultured pearls (Nos. B2 and C1 from the clasp)

With report 1152480853 dated 18 June 2013 from the Gemological Institute of America stating that 187 of the pearls are predominantly natural saltwater pearls and two of the pearls are bead cultured pearls. 

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