Some success today 1919 6d 1890 3d some kinda brooch front but not many good targets.have to put the thinking cap
Is that a black material surrounding the centre? You might have yourself some memorial or funeral jewelry.
Here is a link about mourning jewelry: https://www.thesprucecrafts.com/is-it-victorian-mourning-jewelry-149528
Theres definatly the shape of a cross on there.
At least you didn’t find the hair of a hair bracelet, creepy jewelry!
It doesn’t look like it is set in a black stone in that picture. Was it just discoloration? Because then we are back to square one, maybe identifying the flower will help point a direction?