Old Shell Cameo Pin Brooch

Lovely 1 3/4 x 1 3/8 shell cameo pin. Be sure to click on the picture several more photos and larger images! Pin fastens with early type of safety catch. Frame has a small loop attached, probably for a safety chain - but possibly to use with a neck chain as a pendant. Open back frame of unknown metal content. Metal is not stamped or marked in any way, and we have not tested it for any precious metal. I think this is most likely from the 1930's, but it could be a bit earlier or later. A miniature work of art!