This is a lovely floral design pin of sterling silver mounting with 4 (5 ~ 5.5 mm size) Japanese Akoya cultured pearls.
My guess is from the 1970's to 1980's when these were very popular jewelry in Japan.
There are 2 marks on the back side.
I can only read the [S] and there is a mark in front of it may look like Mikimoto mark but I cannot be sure.
Please see the last photo.
The pin measures about 1-5/8 inches wide and tall.
Condition is previously owned but excellent as shown.
A dime is placed for size reference and not included.