I have found Omni Jewelers and Cardow Jewelers in St. Thomas to be of high quality with nice, non-pushy sales people. Both are in downtown St. Thomas. Make sure to check out the treasure trove at Cardow. They have deeply discounted pieces they have decided to not carry in their store anymore. I got a wonderful deal there last time we were in St. Thomas. My necklace was about 1/4 of the price I was seeing in the states and of equal quality.
Check out www.vinow.com
they might have website links to some of the stores in St. Thomas.