An emerald and diamond convertible brooch

An emerald and diamond convertible brooch, the central rectangular detachable panel set with an emerald cut emerald, approximately 9.97mm x 8.60mm x 4.94mm, approximately 3cts, within a border of twelve round brilliant cut diamonds, flanked by twelve further diamonds, estimated total diamond weight approximately 3.6cts, approximately 5cm long, unmarked white metal, approximately 16.7g