This is a lovely modernist Japanese akoya saltwater cultured pearl star pendant necklace. 

If features a single, lustrous, pearl measuring 6.75mm. It is good quality and has rosy pink overtones. It is surrounded by a modernist star design.

It is set in solid sterling silver but is not stamped. Comes with a solid sterling silver chain, stamped "STERLING". It measures 16 inch. Vintage, mid-century make. 

All pearls are truly vintage and have only been lightly cleaned.