Online shopping is the forum through which you can buy anything online. However, you only need to keep a few things in mind when you go to buy jewelry online, a few things only and the rest takes care of itself. Here they are:
Research the kind of jewelry you want:
The internet is information, pure and simple. All you have to do is type in a few words in your favorite search engine and then select a few from the bazillion pages that show up; I recommend you stick to the first 20 or so. Hunt for some information on the particular kind of jewelry and gemstone you want first, and then shop for it. I recommend Juliana Xerez for online shopping of jewelry.
Look for the following:
a) When purchasing jewelry online, be sure to hunt for a return policy on the website. Usually, this a page filled with legal jargon explaining in great length how the customer will be redeemed of an unhappy purchase within a set limit of time; if you can't find any such page, you are better off looking somewhere else. On this page look for how many days they give you to refund the purchase, reputed sellers will offer around 15 to 30 days like Juliana Xerez.
b) You can also troll some jewelry forums and drop questions there and also read through some of the questions already there.
Be sure to do this. Look for their contact info and send them an email asking as many questions as you want. Now keep the questions meaningful, don't spam them. This will not only help you understand the jewelry piece you want better but also know whether the seller is legit or not and how well they know what they do.
When you buy jewelry online, it will be in your best interest to hunt for as much information as you can before you make your first purchase. This is important as you only have information to go by when you attempt to buy jewelry online. One really good way to try out first is Auction sites (eBay for example). On auction sites, you can find jewelry at extremely low prices, and there are more than enough options to choose. Sites such as eBay also have a rating system by which you can learn how reputed and dependable a seller is. Try buying some jewelry online and rest assured that you will not be disappointed.