This is such a unique and well-done pin. The setting is black and I believe it is bakelite. It does not test with semi-chrome, but it has the look and feel. Black is often very hard to confirm. Also, it could be lucite or jet. The mother of pearl oval is set with two cockatiels sitting on a branch and a bird cage. There are branches and leaves to further enhance this design and add lovely detail.
This pin measures approximately 2 5/8" x 1 7/8" and is in excellent condition.
I could go on and on about the uniqueness and beauty of this pin, but I think the pictures speak for themselves.