cut a groove with a reverse lip into stone (mouth of groove is
wider than bottom)
make a 24k wire with diameter just about 0.0002"’ wider than the
burnish wire into groove
finish with “hammer set” handpiece if needed
with stones that are weak in tension (onyx) you may have to compress
it, with a clamp, before you do the setting, to prevent splitting.
suggest trying a few attempts in a practice piece.
Mark Zirinsky, Denver