There are no guarantees with these tests. But, they just might get you closer to the truth. Of course, the most reliable source would be an independent appraisal, which would probably cost some money. Whatever you do, don't let your jewel be taken out of your site. You could take it to a local jewelry store and get one of their 30 second oppinions for free. Just know that mistakes can be made with these quick judgements. With all that said, let's get to what you really came here for, the do-it yourself tests.
- It is true that diamonds do scratch glass but so do a lot of the other fakes on the market. To boot, it is quite possible to injure your rock even if it's real during such a hardness test.
- If you flip the diamond upside down and place it over some newsprint and can clearly read through the stone, it's not a diamond. Some diamonds are cut shallow and can be read through, so this really only works for larger diamonds.
- The fog test is a good one. Put the stone in front of your mouth and fog it like you would try to fog a mirror. If it stays fogged for 2-4 seconds, it's a fake. A real diamond disperses the heat instantaneously so by the time you look at it, it has already cleared up. Oil and dirt on the stone will effect its reliability. The test is not accurate at all on doublets where the top of the stone is diamond and the bottom is cubic zirconia epoxied together. Did you know that happens?
- The most popular "fake" diamond is a cubic zirconia. C.Z.'s weigh approximately 55% more than diamonds for the same shape and dimension. So if you have a carat or gram scale at your disposal you can see if the imposter tips the scales too much.
- A high percentage of diamonds fluorescence blue when put under an ultra violet light (black light). Since 99% of all fakes don't, a positive identification of medium to strong blue would indicate a diamond. This method proves you have a diamond. It also proves your diamond is worth less. Diamonds with blue fluorescence are as much as 20% less valuable. Remember, lack of blue fluorescence doesn't mean it's a fake; it could just be a better quality diamond.
- If you own some sort of magnifying lens, there are some things you can look for on the stone that might give away its identity.
- Look at the rock from the top and see how well the facets are joined. They should be sharp.
- Look at the girdle and see if it is faceted or frosty (clear sign it's a diamond) waxy and slick (indicates it's a fake).
- While you're looking at your stone under magnification, look into your stone to see if you detect any flaws (carbon, pinpoints, small cracks). These are typically clear indications it's the real thing since it's very hard to put inclusions in a fake.
- After examining the stone, focus in on the stamps inside the setting. A stamp of 10k, 14k, 18k, 585, 750, 900, 950, PT, Plat indicates the setting is real gold or platinum which gives a better chance that the stone in it is real as well. While your're looking at the interior of the ring, also look for any C.Z. stamps.That would indicate the center stone is not a diamond but a cubic zirconia.
I hope this helps a little bit and I wish you luck on your sluething.
