Just an addendum to firing stones in metal clay…there is an
excellent list of stones that will survive firing, researched by
Kevin Whitmore at RioGrande
There’s also Natural Gemstones in Metal Clay. A Bench Resource
Manual. by Deric Metzger, available on Amazon.com. Metzger is very
thorough, as is Kevin.
I prefer to set stones after firing, because I always fire at 1650
degrees F (900 C) for two hours, for strength and density, no matter
which type of clay I use. I either use fine silver bezel wire or
cups or use the clay itself to form the bezel. There are hardly any
stones that will survive my firing schedule or temperature.
Hope this is helpful,