If you are thinking about drop shipping (or working wholesale) jewelry there is a few things I want to make sure you are aware of. Most people when they think about products they want to sell online, jewelry is one of the first things that comes to mind because it can be such a high ticket item. We often let "greed" cloud good judgements, and that should not be the case with an internet business.
If you are wanting to sell jewelry online then you should conisder narrowing down a niche. You ask a niche with jewelry? Jewelry is Jewelry right? Take a second to think about these different jewelry niches - Pet Jewelry, Christian Jewelry, Celtic Jewelry, or a specific Religion Jewelry etc. These are just a few of the top of my head. You see where I am going with this? You have to narrow it down instead of being so general, or you will never be able to compete.
When looking for a jewelry supplier make sure you find one that will let you narrow down the product to a specifi niche to make it easier to compete. If you are looking for more ideas to narrow down the "jewelry niche" then use a keyword suggestion tool like the one at http://www.digitalpoint.com/tools/suggestion and that should give you a great idea as to what people are looking for (so you can narrow down a niche).