Jewelry is quite the PITA to shoot. My fiancee makes lampwork beads and jewelry pieces with them and it's been a several year learning curve to get decent shots of them. I first tried shooting in auto and playing with flash exposure compensation. Not so good. Tried in sunlight under various iterations of light tent - shower curtains draped over chairs, printer paper formed into a tunnel on a bent up coathanger, a cheap little nylon light tent about 1 x 1 x 1'. Still not so hot. Then multiple flashes indoors, including one from below through frosted glass, again using the cheapie light tent. Getting there, but still the beads had giant hot spots with no detail.
My latest attempts have been the best so far - indoors, multiple flashes. The MT24EX on an off camera cord with both heads high and to the right, about 30" away and 18" above the subject (about 5 o'clock if looking directly down on the subject, with the camera at 6:00), and my 550EX as a slave ~18" away at about 8:00 on the stand with a lumiquest reflector on it; both in manual at 1/32 power, camera at 1/60 and bracketed around about f/11 to find the best exposure. I'm using a 24-70 f/2.8L or the 100mm f/2.8 macro depending on the subject size.
Keeping the flash heads relatively far away from the rounded bead seems to result in much smaller hotspots than trying to light it close up with the big tent did. It was simply reflecting the whole tent in a big white blob.
Keep experimenting and playing with lighting and you'll start to figure it out.
Good luck with it!