So, from anyone who has faced and conquered this problem, how
to reduce the metal "splash and flash" while showing the best light
on the opal fire?
As you say, this is digital. So cheat digitally. Set up your
diffusers and shoot for the best look of the metal. Then, without
changing the position of the piece or camera, remove the diffusers.
Shoot again. Use various spotlights on the opal to shoot several
versons of this shot with various lighting, trying to optimize the
opal appearance. Then export all shots into photoshop or another
similar photo editor. choose the shot in which the opal most
closely resembles it's real self in normal viewing to the eye. Cut
and paste the image of that opal into the shot where you optimized the
metalwork. Edit the result as needed to clean up any visual clues
that this is cut and paste.
These days, virtually any image can be trusted only insofar as the
assumption that it's been edited. So join the crowd. Remember the
aim is to get the piece not to just look it's best, but also to get
the image to look most like the piece does. You don't want to make
the opal look better than it really is. that would, of course, be