This is a lovely quality Japanese saltwater akoya cultured pearl and yellow gold bar pin or brooch. 

The the pearls are lustrous with rosy overtones. They measure 5.00-6.00mm. 

Measures 1 5/8 inch long. Not stamped but tested as solid 14K yellow gold. From mid-century. It can be worn as a brooch or possibly a pendant or shortener for a large strand.

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