This gorgeous pin stumps me! It has the number 100 on the top, so I assume this is a centennial piece. The quality and design leads me to believe it is an unsigned Boucher, possibly phrygian cap hallmark, circa 1940's. The shape is a modified heart or crest. It has pave set clear rhinestones and square cut aqua stones. It is rhodium plated with a gold wash finish.
The condition is excellent. It is a really beautiful brooch measuring 2.25 x 1.75 inches.