Natural pearl, seed pearl and diamond necklace, late 19th century. Estimate 5,000 — 7,000 GBP. Photo Sotheby's

Designed as two plaques of scroll design, set with circular-cut diamonds and natural pearls, connected by chains set with seed pearls and similarly-cut diamonds, to a later fine link chain, length approximately 400mm, detachable brooch fitting, fitted case. 

Accompanied by SSEF report no. 77662, stating that the six pearls tested were found to be natural, saltwater.

Sotheby's. Fine Jewels London, 18 Mar 2015, 10:30 AM