I believe I used air dry clay for the design inside the Patera.
Black air dry clay rolled onto a Clay Squisher and then I used a heart shaped cookie cutter to get the right shape but you could cut with a knife and then leave to dry.
Once dry I coloured with blue Mica Gloss.
I used a liquid glue inside the Patera like Diamond Glaze or Glossy Accents and then filled in the gap around with micro glass beads.
You could then cover with a glaze or resin to protect it but I have left mine open for texture.
We have patera currently on sale @ 70% off in different shapes, sizes and colours.