Although just a touch overexposed (or said more properly, your lighting is a bit "hot" which has resulted in overexposed areas), that is your best photo, IMO. To make this photo even better, I would try and move the lights "higher". This may not be possible if your camera lens is too short (i.e. you can't get enough working distance to move the lights higher) -- and if so, now you know why coin photographers tend to prefer longer lenses for full shots of lustrous coins.
Thanks for the lighting advice....here is another shot with lights further from the object and other options similar to the one you liked. Thoughts on this one...it is very similar in coloration to the one originally selected as the winner...but I think there is even more detail. Anyone else have opinion.
Your white balance is off, there is a greenish-yellow tint to your pics and if your background is white; it looks gray. However, the detail on the image looks much better; keep up the nice work. -LTB