Your first priority should be the mechanical aspects of it. Is the
stone suited as is to being held in some manner? Can you saw it in
half perhaps and get two sorta like pseudo cabochons? having a flat
back will go a long way in suggesting how to hold it. Get a good
bearing and the rest isn’t so hard. Prongs or bezel, depends on the
shape of things. Or a combination of the two.
How well formed is the crystal? Can you use that to your advantage?
Sawing isn’t as big a job as it sounds. A diamond wheel in the
flexshaft could do it if you’re careful to avoid heat buildup and
maybe you could drill thru it and use a wire to hold the thingie in
place. Ballup the ends or make it a screw. I once used a 4 ct diamond
in a bezel mounted on a screw to hold an onyx saddle ring together.
Grind a groove around the largest circumference and use that as your
bearing surface, like the old scarab bracelets kinda, but double
Ok my head hurts now from thinking.