Antique Victorian Monogram C.G.G.B. Initials Cutout Brooch

Antique Victorian or Edwardian gold filled or plated cutout monogram cipher brooch with initials C.G.G.B.

Good condition. The pin stem was coming loose so I repaired it with a laser.

Back has an unknown grayish silver metal. I initially thought it may be lead however after testing with multiple acids I believe it is a different metal.

Measures approx 1.9” x 0.9”