We use black femo.
It not only brings out the colors of the opal but also cushions it
as it is being set and worn by the owner.
Good luck,
Laurie
Do you mean you bake the Femo? Or leave it as clay? I would think
it would dry out and crack if it weren’t baked…
Janet
PS - I’ve used a technique similar to Doug’s – I mixed epoxy with
black enamel powder.