Vintage 925 sterling silver necklace w two tone pink and white oyster pendant

Vintage sterling silver necklace with natural oyster shell. The pendant is two tone, one side is light pink, the other - white mother of pearl. In excellent condition. The chain is 16" long and stamped 925 on the clasp. The pendant is 2 cm long (with bail) and not stamped (or the stamp is no longer visible). It was professionally tested as 925 sterling silver.