You really can not be certain if a diamond is geniune unless you confirm it with a certified gemologist or jeweler, or that you can be certain there is a reputable gemologist or jeweler. There are, however, a few tests that you can take. The following are a few matters you can perform, such as: is newspaper readable through the stone? If so, it is not a genuine diamond as diamonds have so many refractions light cannot pass through in a way that would allow you to read anything. Also if the diamond is glued into the setting, it could likely be a rhinestone, as diamonds are almost never glued into their setting.
If the stone has a closed back it likely is not a true diamond. Although some diamonds may have partially closed backs, usually the bottom of the stone will show through in the case of the real diamond. An experienced jeweler or gemologist would be able to tell in the case of antique jewelery by checking on the underside of the mount. In cases where an antique or family heirloom jewelry is taken in for cleaning or an appraisal to find that only the top cut of the diamond was present, but then amidst the mount, a lesser diamond below.
Silver foil has long been used to be hidden in the middle of a setting under a shallow top, or crown of the diamond. This is an effective technique in creating a fraudulent diamond. The silver foil acts as a mirror to create the impression of a diamond in refracting light. Foiling done today can end up making the back facets into true mirror, and then placing a protective coating of gilt paint and then set in jewelry so that their backs are hidden. Some experts suggest that up to five percent of all jewelry are fraudulent or mis represented.
You should also doubt you have expensive jewelry simply because it has been passed down and long treasured, as it has always been a fact that some unscrupulous jewelers are keen to prey on unsuspecting customers. You want to also look for how many facets are visible on the top of the diamond. In cheaper glass imitations only nine top facets are usually visible, as opposed to thirty three facets inside the top facets of a diamond. Single cut or Swiss cut diamonds will show also only nine facets on top, but they will be set in open back mountings. In contrast cheap glass imitations are usually set in closed back mountings.
You also want to check on whether the middle, or the girdle of the diamond appears to be frosted. The girdle of most diamonds are unpolished, with a ground glass like appearance that suggests frostiness. Some diamond imitations also have a frosted appearance, but of all these, a diamond has the whitest frostiness, like clear, dry ground glass. However, some true diamonds do have a polished girdle and therefore will not have frostiness. You can prepare your eye to look for these differences, and by dealing with reputable jewelers you should be able to avoid such pitfalls.
In fact, you can have a jeweler show you the difference between a polished girdle and an unpolished girdle, and a faceted girdle. You also need to ensure whether the cut is symmetrical or not. An expensive or fine diamond will have been carefully cut, whereas in cheaper stones or imitations there will be less care and caution taken. Are the crown, or top of the diamond and the pavilion in alignement. Are the facet edges scratched, chipped, or worn. Imitation diamonds are either very soft compared to a diamond, or very brittle. One of these imitations is called Fabulite, which is an artificial diamond.
Fabulte is a simulated diamond also known as a Wellington Diamond. Like most other fraudulent diamonds their softness has them wear down at the edges whereas a diamond does not. Only Zircon of the bogus diamonds is hard, yet brittle. So check the edges carefully. And here again make sure you trust your dealer and that it is a guaranteed understanding that the goods can be returned if you check on arrival and want to return the goods.
When you check the flat faces for wear, you also need to check for nicks and scratches on the edges. If you do your homework and take care on who you deal with, and in this way the finer majesty of the real diamond will show itself to you.