1920s Vintage Louis Rousselet French Art Deco Vauxhall Glass Flower Brooch

Incredible and extremely rare late 1920s brooch by French parurier Louis Rousselet. Three dimensional dome constructed primarily of extremely fine wire, with amber vauxhall glass rhinestones covering the surface in floral pattern - a round central stone and half-moon montees as flower petals - and finished with a trombone clasp closure. Absolutely stunning piece, in beautiful condition for its age, with some signs of wear consistent with age and use. For example, the stones are all secure to the brooch, but some are looser than others. I’m not certain, but I believe this may be one of the pieces Rousselet created for Chanel. In 1929, they created a series of pieces for Chanel using the same montee rhinestones, e.g., necklaces where the stones were arranged in a slightly different pattern to create rosettes. But I have not been able to pin down with certainty which couture house this particular design was created for.