Abalone/Mother of Pearl Sterling Silver Necklace

Vintage Sterling Silver mother of pearl/abalone necklace. Signed NF (nickel free?) Thailand on pendant. This is an Italian made NF (nickel free?) sterling silver chain. Purchased used but never used. Still looks great!!! The chain measures 17" to 17 1/2". The pendant is 1 1/8" tall from hook. The pendant is 3/4" tall and 5/8"wide. Has a Yin Yang look/style