The single most important factor above the piece being genuine, natural, lab created, or anything else is simply that you really like the piece and feel good about your purchase.  Yes other factors are important, but this is the one that will play on your mind long after you have placed a receipt or an appraisal certification in a drawer or vault.

There is much debate and even snobbery in jewelry buying that it borders on ridiculous.  If you prefer to have a certified genuine piece on your finger then by all means that is what you should buy.  This does not make you a snob it makes you someone that prefers the real thing.  On the other hand if price is more important to you there are lab created gemstones that look even better than genuine ones and this does not make you cheap to own one, it makes you thrifty.

Do your homework and know the terms and types of stones. Buying jewelry online makes one apprehensive at best, especially rings. Will it fit? What if I don't like it? These are but a few of the questions. BUT buying rings on eBay also allows one to purchase them at significant savings.  Rings simply do not sell for what they are worth in a Jewelry Store on eBay and they shouldn't, because you can't touch the ring before you buy it. That means savings to you, so read the description carefully, look at the pictures, check the sellers feedback, refund policy, and ask questions.

You may have trouble finding a ring that is your size as many rings today are made in a size 7 only. Don't despair, the savings you obtain from your purchase on eBay can easily cover the cost of having a ring sized by a local reputable jeweler. The production of rings in limited sizes allows them to be made and sold at lower cost. Some rings can not be sized due to their setting or stones, so check the item description. The best place to have a ring sized is indeed your local jeweler so they can measure you for an exact fit. Retail jewelry stores that size rings are quite familiar with sizing rings that were purchased elsewhere, and they charge a reasonable small fee for doing so.

It is all a matter of personal taste and preference. The deciding factor in purchasing any piece is up to you as it well should be.  We can not control those that for the sake of interest or snobbery are going to ask details about the ring on your finger and how you respond to them is a personal decision.  Jewelry often becomes a topic in conversation and if you are going to feel bad about telling someone a stone is lab created then by all means avoid them, if you do not then by all means say so, or don't, or come up with a clever answer or do anything you need to do.  Preference is the spice of life, feel good about your choices in jewelry no matter what they are, as each piece of jewelry is as unique as you are!