This is gold vermeil. I have fallen in love with gold vermeil. It has such a dainty look. This is only one of several pieces of this I have bought recently, All of them are even prettier than they look on line.
The photo captures much of the beauty, yet when the light shines from the stones, and they are seen in three dimensions, this brooch is even more elegant. Heirloom for sure. Quite sturdy and substantial.