Silver-Topped Gold, Sapphire, Natural Pearl, Diamond and Enamel Pendant-Necklace, circa 1870. Estimate 8,000 — 12,000 USD. Photo: Sotheby's.

Of openwork design, decorated with scrollwork and floral flourishes, centering an oval-shaped sapphire measuring approximately 8.8 by 6.6 by 7.4 mm, accented by smaller round and oval-shaped sapphires, supporting a natural pearl drop measuring approximately 7.7 mm, further set with old European and single-cut diamonds measuring approximately 1.70 carats, highlighted with green, red and black enamel, chain length 15½ inches; circa 1870. With fitted box and brooch attachment. 

Accompanied by GIA report no. 2175217338 stating that the pearl is natural, saltwater.

Sotheby's. Important Jewels, New York, 24 sept. 2015