Antique gold diamond and black enamel key brooch

An antique 15k yellow gold black enamel diamond lock and key brooch - a padlock covered in black enamel with an old cut diamond set within the key hole and suspended below a black enamel bar brooch with screw motifs to each end and a gold key bound to the bar by a band of seven rose cut diamonds - finished with a C clasp fitting to the back - weight of diamond 1=0.16cts - total weight 15.82grms - overall dimensions 54 x 36mm - c.1860 Europe