I used a Cernit and Fimo mixed green for the background of these and it works well.
These next beads are made using only Cernit for the background. The canes are mostly Fimo and the two clays do not work together in this way. The canes do not merge into the background at all and the white translucent background of the cane turns mostly white during curing. I won't be using a cernit only background again.