Buying A Created Diamond On eBay
Many buyers will turn to eBay when searching for a lab created diamond. It is certainly possible to find some bargains, usually second hand. You do have to be careful online though, because there are a lot of unscrupulous sellers who will pass off much cheaper substitutes as real lab created diamonds.
As a rule of thumb if the price is just ten or twenty dollars, chances are you are looking at a cubic zirconia or another synthetic diamond. The costs involved in making a lab created diamonds can be quite substantial – to end up with one carat of finished cut diamond you need a few carats of rough diamond. Gemstone cutters charge by the carat, and this might cost $1-200. Even if the diamond didn’t cost a cent the seller would still have to charge at least $400 per carat just to break even, and obviously the raw diamond itself is not free. So if you see someone selling man made diamonds at less than $100 a carat you can be pretty confident it is not real lab created diamond, regardless of what they claim.
Read the description carefully! If it says simulated lab diamond it is probably not a genuine lab diamond. If it says it is a Russian lab diamond, it is most likely cubic zirconia (cubic zirconia is often called a Russian diamond).
The absolute best way to make sure you are getting a good quality created diamond is to buy from a reputable source either online or in a real shop, and make sure it comes with some kind of certification from an independent lab. Most created diamonds these days should come with a grading report.