Cubic zirconia or moissanite usually cunningly resembles the real diamond and might be even sold as one by crooks.it is laboratory manufactured unlike the real diamond that naturally exists.

The jewelry market has been flooded with synthetic stones over the last several years; not just lab-grown gems but flat-out fakes. Here's how to tell if your rock is the real and not just a shiny bauble.

1)If the stone is not mounted on a ring or setting one can place it on its head on a written or printed paper. If you can read the papers print at all, the stone's probably fake. In fact, if you look through the top of a real diamond, its high refractive index will prevent you from even seeing the bottom point of the stone. Similarly, if you place the gem atop a dot drawn on a piece of plain white paper and you can see a circular reflection in the stone, that rock is not diamond.

2)Being products of natural processes, mined diamonds often have a mild yellow or brown tinge and will include flecks of other minerals, within their lattice structure. Fake diamonds, on the other hand, are generated in sterile environments and are therefore flawless. Also one can take a look at the girdle of the stone. If the girdle is smooth or rounded, the stone's fake since diamonds always have flat facets; they're never rounded.

3)Fake diamonds weighs roughly 1.7 times as much a diamond of the same volume. It is actually a much denser than the real diamond. If you have a non-mounted stone place both stone and a real diamond in your hand and bounce them gently, you should be able to immediately tell whether your stone is the heavier, lighter or of the same weight as the diamond.

4)If you breathe on a real diamond, trying to fog it as you would a pair of dirty spectacle lenses, it will not fog up. Since diamond is such a potent heat conductor, the fog will dissipate instantly. If you notice fog as you pull the stone away, it's likely a fake.

5)Jewelers will most likely have an electrical Diamond/Moissanite Tester on hand since it is nearly impossible, even for trained appraisers, to tell the difference between moissanite and diamond by looking at them. These handheld devices run a small amount of electrical current through the stone to measure its conductivity. Since diamond and moissanite conduct electricity at differing efficiencies, they can quickly be differentiated using this method.

6)To test whether a diamond is real or not, a jeweler's Thermal Conductivity Diamond Tester (typically a heat probe) is used. These employ a pair of thermistors to measure the amount of heat that is conducted from the device's hot copper tip to the stone. And since diamond conducts heat more efficiently than synthetics, if your stone is cool to the touch after applying the heat, it's very likely real.