A 19th century onyx and diamond mourning pendant

A 19th century onyx and diamond mourning pendant, the oval onyx front set with a raised tréflée cross set throughout with old cushion and mine cut diamonds and one central rose cut, the bale with three more rose cuts, the back of the pendant with glazed panel of curled hairwork bound and decorated with gold wire; at present the pendant is sewn to a black ribbon bow; length with bale 6.0cm, total estimated weight of diamonds approximately 1.50cts