This is a lovely vintage designer Mikimoto Japanese akoya saltwater cultured pearl circle pendant.

The pearl measures 5.00mm and has fantastic luster with bright rosy overtones.

It is set in a solid sterling silver circle with milgrain edging. Stamped "M" in a clamshell for Mikimoto and "SILVER" for sterling. Total pendant length is 5/8 inch, it is petite. From Japan 1950's-1980's. Chain measures 16.50 inch. 

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