Once you have pressed your clay into your mold for an impression, take a blank pendant tray and
press it gently down onto your clay to create an outline. Cut out using an x-acto knife/razor blade.
Gently place the clay into your pendant, making sure it fits well. This is a good time to apply a finish
such as perfect pearls, a metallic pigment powder that sticks to the raw clay.
Then bake the clay while it sits in your metal pendant. Once it has
cooled down, remove the clay from the pendant tray.
Seal with your choice of sealer (Polycrylic clear gloss is my favorite,
found in a spray can at most hardware stores near the wood
sealers and stains.)
Glue it back in place with a strong adhesive rated for plastic to
metal adhesion (I use E-6000.)