Fine silver bezel wire
Can be imbedded in silver-clay and fired, it will not shrink as the clay does.
Or fire the piece, wrap the bezel wire around your irregular stone. Carefully, preserving the shape, glue the bezel wire to the fired sliver-clay with slip and re-fire.
WARNING: This product can expose you to chemicals including Silica, crystalline (airborne particles of respirable size), which are known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.