In our last post, we talked about getting to know the ways in which your diamonds are unique. But if you’re a lover of this stone, you also should know how to tell whether a diamond is real. Of course, no homespun test is guaranteed–coming in to our store and having our skilled appraiser evaluate your stone is the best way to know if it is real, and what it is worth! But here are some tips that can help you get an idea of whether the sparkler you have your eye on is genuine or not.
1. Diamonds conduct heat really fast–much faster than a synthetic stone does. This means they heat up and cool down quickly. You can use this factoid in a few different ways. The first is just to hold the stone in your hand for a few seconds, until it feels warm. Then, using tweezers, pick it up and touch it to your lip; it should feel skin-temperature. Then set it down, wait 10 seconds or so, and try again (still using tweezers). You have a synthetic if it still feels warm, neutral, or anything other than distinctly COLD; a natural diamond would already have lost any heat.
You can also do a similar test by breathing on the stone. Hold it up in front of your mouth and exhale on it as if you were cleaning a pair of glasses. If the surface of the stone fogs up and stays fogged for a few seconds (2-4) then it is a synthetic. The surface of a natural diamond will have cleared up by the time you look at it! If you can, repeat this test on the bottom of the stone since sometimes a synthetic will be made with a real diamond surface.
Center stone is lannite (synthetic diamond)
2. If your stone isn’t in a setting, you can just try to read through it. Set it flat-side-down on a piece of newspaper; if you can clearly see the print through it, then you have a synthetic. Note that this only works with deep-cut stones, since a natural diamond that is shallow will also be transparent enough to read through.
3. In a similar test to the one above, place a loose stone over a thin line on a piece of paper. If the line appears to be immediately beneath the stone (i.e, where it really should be) then you have a synthetic. But if the line can’t be seen at all, or if it appears to bend, then you have a real diamond.
4. Take a close look at the structure of the stone using a magnifying lens. The edges of the facets on a natural diamond will come together in a very thin line; in a synthetic, they will look rounded or glassy. Also, a real diamond is likely to have small, natural flaws called inclusions; these are almost impossible to include in a synthetic. If the surface of the stone is scratched, odds are that you have a fake (though there is a slim chance it is an old and battered real diamond). And of course, if your stone is set, check for stamps in the metal–a C.Z. stamp indicates it is a cubic zirconia.
5. If you have an ultraviolet bulb handy, look at the stone under that light. A synthetic will almost never glow blue under the UV light, whereas many diamonds will. The catch is that the best quality diamonds also won’t glow blue. So if your stone doesn’t fluoresce then you know you either have a fake, or a natural diamond of excellent quality–one or the other!
6. Cubic zirconia, a common synthetic, will nearly disappear if you submerge it in water, whereas a natural diamond remains clearly visible (this test doesn’t work with other kinds of synthetic diamonds though).
7. Moissonite, another common synthetic diamond, is extremely sparkly in sunlight, but fairly dull when indoors under incandescent light.
8. DO NOT test your stone by scratching glass with it! A real diamond will indeed scratch a window pane–but so will some synthetics, so it’s not conclusive. But more importantly, glass can abrade the surface of the stone, dimming the sparkle of even a real diamond–and it’s even more likely to damage a synthetic, which is valuable in its own right.