What is the best way to distinguish a cubic zarconia from a real diamond???

Question

How should I check to see???What different methods should I use???Thank you....

Answer 1

Cubic zirconia is so optically close to diamond that only a trained eye can easily differentiate the two. There are a few key features of CZ which distinguish it from diamond, some observable only under the microscope or loupe. For example:

Dispersion. With a dispersive power greater than diamond (0.060 vs. 0.044) the more prismatic fire of CZ can be seen by even an untrained eye.
Hardness. CZ has an 8.5 to 9.0 on the Mohs' hardness scale vs. a rating of 10 for diamonds.
Specific gravity. CZs are heavyweights in comparison to diamonds; a CZ will weigh about 1.7 times more than a diamond of equivalent size. Obviously, this difference is only useful when examining loose stones.
Flaws. Contemporary production of cubic zirconia is virtually flawless, whereas most diamonds have some sort of defect, be it a feather, included crystal, or perhaps a remnant of an original crystal face (e.g. trigons).
Refractive index. CZ has a refractive index of 2.176, compared to a diamond's 2.417.
Cut. Under close inspection with a loupe, the facet shapes of some CZs appear different from diamonds.
In theory, many gems (such as CZs and diamonds) look best when the star facet, crown main facets, and upper girdle facets do not quite meet. (Per Step 11 of editor's note 36 to Marcel Tolkowsky's Diamond Design.) Diamond has such a high refractive index that having these facets meet at a single point does not cause much loss of fire or reflection. Diamonds normally have these facets meet at a point, because that is more symmetrical and reflects well on the cutter's precision. On the other hand, CZ has a considerably lower refractive index than diamond. CZs are often cut with 6-sided crown main facets, so that the star facets do not touch the upper girdle facets. This optimizes the brilliance and fire of the CZs.
The optimum angle of the main crown facets is steeper for diamond than for CZ. (According to Tolkowsky's model of the crown, for a given pavilion angle and girdle thickness). CZs are often cut so that the crown main facets do not touch the girdle. This allows the CZs to have a shallower crown angle, while still having the same crown height as a diamond with a similar cut.
Color. More precisely, the lack of color: Only the rarest of diamonds are truly colorless, most having a tinge of yellow or brown to some extent. By comparison, CZ can be made in most cases entirely colorless: equivalent to a perfect "D" on diamond's color grading scale.
Thermal conductivity. CZs are thermal insulators whilst diamonds are among the most efficient thermal conductors, exceeding copper. This makes telling the difference between diamond and CZ quite easy for those with the right tools.

Answer 2

The glass cutting test is useless as nearly every stone will scratch glass. A good, quick test which I often use is based on the thermal conductivity of diamond. If you have an unknown stone first allow it to come to room temperature (if it is in a ring someone has been wearing leave it on the desk for 4 or 5 minutes) pick it up with tweezers and then breathe on the stone which will mist over. The speed with which the mist clears will tell between diamond and most substitutes. Diamond clears almost instantly whereas most substitutes take longer. This is not an easy test and you need to try it out many times with known diamonds and other stones to learn the difference but with experience it is very effective.

Answer 3

The only way I've heard is to look at it under a jeweler's glass. If it's perfect, its CZ. If it has flaws, it's a real diamond.

Answer 4

cubic zircon will not cut glass and a diamond will. diamonds are the hardiest substances known to humans