Antique brooch end of the 19th century

Very rare mourning jewellery; end of the 19th century. Large and heavy antique brooch with a beautifully worked leaf setting (no hallmarks, probably silver, not tested), in the silver setting is a finely worked obsidian or french Jet cameo with a woman's head (cameo carved on lava stone or french Jet), on the back the circular chips can be seen very well, indicating the material obsidian or frensh Jet; pin intact but loose; traces of use according to age (see photos); Dimensions: approx. 5 x 4.5 x 2.5 cm / 30.2 g