How to Tell If a Diamond is Genuine

Observe the diamond closely. Real diamonds have flaws while fake versions contain no imperfections. The tiny "flaws" on real diamonds help create their brilliance that fake diamonds lack. Examples of diamond flaws include tiny crystals and minerals embedded within the diamond, or tiny light or dark crystal clusters that create a hazy area in the piece.

Flip your diamond over and place it on a piece of newspaper or printed magazine page. If you can read the print clearly, it is not a real diamond. Note that you might be able to see print through some low-cut diamonds and other gems such as emeralds.

Hold the diamond up to your mouth and breath on it as though you are trying to fog a window pane. Real diamonds disperse heat immediately, meaning you will not be able to see any fog marks when you observe the diamond.

Observe the diamond for signs of wear and tear. Real diamonds are incredibly hardy and cannot be scratched. Faux diamonds are subject to nicks as well as scratches, whereas real diamonds can scratch glass.

Use a carat or gram scale to test the weight of the diamond. Diamond weights are measured in carats, and one carat equals 1/142nd of an ounce. Therefore, a diamond that is 5.5 milometers in size weighs .5 carats, a diamond that is 6.5 milometers weighs 1 carat, a diamond that is 9.3 milometers in size weighs 3 carats, etc. Faux diamonds such as cubic zirconia will weigh 55 percent more than a diamond of the same size and shape.

Place the diamond under a black light or UV light. Most real diamonds will show a fluorescent blue color under such lighting whereas fake diamonds will not show any color.

Observe your diamond from the top to see how the cuts of the diamond, or facets, are joined. Real diamonds will have sharp, not rolled, cuts.