The first thing on your priority list should be to find a reputable online dealer to shop from and then you can work from there.
You basically have two options when you are browsing websites in search of great deals on designer gemstone rings.
The first option is to buy from the designers websites themselves such as the David Yurman website.
You will find a multitude of choices there but at the same time you are going to be paying top dollar.
The other option is to consider shopping for replica designer gemstone rings and they will come in a broad range of prices that will give you more options.
What you don't want to do, is pay top dollar for the genuine article and end up receiving a cheap imitation and it does happen to online shoppers who aren't careful who they are dealing with.
Make sure that you check the feedback on a website before you consider shopping from it and don't be afraid to ask any questions about the pieces that they have for sale.
Rule number one, is that if the deal sounds too good to be true then chances are that it most likely is.
Also, beware of deals that offer a certificate of authenticity, because they too can be easily counterfeited as too can authentic looking jewelry cases.
In fact, you can find David Yurman designer gemstone rings for sale on the Internet that come with certificates of authenticity and David Yurman doesn't even provide them with the pieces that he sells from his website.