Art Deco Platinum, Diamond and Natural Pearl Necklace. Photo courtesy Doyle New York.

The delicate chain continuously set with 79 collet-set old European and single-cut and 3 baguette diamonds approximately 2.10 cts., accented by 2 old European-cut diamonds approximately .80 ct., suspending 2 pearls approximately 8.8 x 6.0 mm. and 8.2 x 7.0 mm., with single-cut diamond-set caps, circa 1920. Lengths 16 1/2 and 18 7/8 inches. With original fitted box. Estimate $18,000-22,000 

With GIA report no. 5151549376 stating that the pearls are natural, saltwater, no indications of treatment. 

Doyle New York. Important Jewelry. Wednesday, September 25, 2013 at 10am - http://www.doylenewyork.com