From the looks of several pieces...they are too shiny and modern to be older or "Victorian" mourning jewelry. I don't know how else to explain it.
Most "mourning jewelry" is made out of hair or the semiprecious stone, jet (where the saying "jet black" came from). There were other stones used...however they incorporated the human hair into the jewelry to go along with it whether it be a braid, locket of hair, hair weaved into intricate flowers, watch bands, rings, bracelets, etc....
If you could get better closeups of clasps...you can tell the older ones by style.
As for the last piece, it could have been worn in the hair. They also made them in this fashion and they were sewn onto sweaters/capes/shawls. This simply could have been removed from one. This one does look typical of the time period.
Does the one in the top left picture (first pic) have dark human hair in the middle? like this one? Can't tell from your picture.