Antique Vermeil Sterling Filigree Hand Carved Shell Cameo Brooch of Saint Peter c1900

Exquisite carving - assume cameo is Italian - unidentified signature as seen in photograph - the setting is a fine filigree bezel mount - small ding but no loss and solid - retains traces of original gold vermeil plating - marked only: STERLING - The brooch is slightly oversize measuring 2 1/8 x 1 3/4 inches with an added bale loop and original pin, hinge and clasp for brooch - all in good wearable condition - weighs approximately 16 grams - The image depicted is a profile portrait of a man in early Roman dress with Giottoesque eyes, curly beard and hair - however this man has a halo and a set of keys in his hand - assume Saint Peter with the Keys to the gates of Heaven - rare and wonderful.  Cameo may be earlier than the setting.