Thought #1 – If you cut out
Thought #1 –
If you cut out a piece of irid and glue it to a piece of opalescent and fire it.
Then paint glue over the irid and let it dry completly, maybe even 2 coats.
Then sandblast the opalescent. Then soak off the glue. The irid looks great in contrast to the sandblasted opal. Then you can slump it.
Thought #2 – Also you can glue white shelf paper (self adhesive) over a piece of irid.
Draw a design and cut it out removing hte pieces where you do not want the irid to show. Then sandblast off the irid that is not covered up with the contact paper
Strip off the contact paper that is cover ing up the irid to expose the design. Then slump.