Extremely well made, this pin has several unique features. The 8mm pearls actually are set to hang loosely so they actually dangle. There are round and marquise faceted foil-backed rhinestones that are each prong-set. The prongs and darkened metal framework were clearly designed to become part of the overall beauty of the piece.
The pin measures 2 1/8" x 2". The clasp is a pull-barrel style. Definitely very early 20th century or possibly late 19th century.