Hi Paul, thanks for writing in. This fascinating brooch looks like it might be Egyptian Revival jewelry which was made during the 1860-70s which copied the overall appearance of Ancient Egyptian Jewelry. The articles included brooches, necklaces, earrings etc.
In 1869, the Treasure of Priam" was discovered by Heinrich Schliemann in 1869. During this time, jewelry designs were inspired by archaeological and earlier finds.
