Vintage Carved Shell Cameo Filigree 1920? Brooch

Vintage DEEP carved shell cameo brooch....probably from the 1920's. Wonderful detailing in hair, face and flowers. Pretty, sweet face! Shell is domed, nice color contrast. Translucent. I see no cracks, chips or stress lines. Filigree mounting...questionable what the metal is? Looks brass or almost looks spray painted gold? Measures 1 3/4" x 1 1/2". Very pretty piece!