This is a vintage mid-century Japanese saltwater akoya cultured pearl and sterling silver brooch or obidome

The pearls are highly lustrous and measure 5.75-6.00mm. They have rosy pink overtones and are white in color. 

It is made of solid sterling silver and has cross hatch texturing on the arrows. It is stamped "STERLING" for solid sterling silver. It measures 2 1/2 inches long. From Japan, 1940's-1980's. It has two loops on the back and can be worn as an obidome (or kimono belt ornament). 

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