Updated date:

Fake Diamonds - How to Tell if a Diamond is Real

Author:

Robert writes articles that offer useful, practical advice on a variety of topics.

Is it a real diamond?

How to Tell if a Diamond is real

How to Tell if a Diamond is real

This article explains how to tell if a diamond is real or fake.

You may have come across some jewelry in your late grandmother's attic or at an estate sale that you want to know if it is diamond or not. Some costume jewelry is very difficult to distinguish from a real diamond. The best way to tell if it is a diamond, is to have it looked at by a gemologist. He or she will have access to special tools that can help identify whether the stone is a diamond or just a shiny bauble. But if you want to try to figure it out on your own, there are a number of tests that you can do at home.

There are a number of ways that you can tell if a diamond is real. These methods of testing the authenticity of diamonds are based on the unique properties of real diamonds which are not found in other substances. The characteristics are not shared by imitation diamonds such as cubic zirconiums or other fakes.

An Important Note About Testing Diamonds

Identifying and grading diamonds is a complex process which involves a great deal of knowledge and expertise. Only a competent jeweler or gemologist can tell for sure if a diamond is real.

You should not use the information in this article to make decisions on the value or authenticity of any particular stone. Always consult with a reputable diamond professional. Even if the diamond in question seems to fail any of the tests outlined on this website, you should not conclude that it is fake.

Conversely, even if the alleged diamond passes the tests outlined on this website, it does not mean that it is a real diamond. It may simply be a very good artificial or imitation diamond. The only way that you can tell for sure if a diamond is real is by seeking the advice of a reputable jeweler or certified gemologist.

Not everything that looks like a diamond is actually a diamond. This is a picture of  the Chalmers Topaz which is 5,899 carats and weights over 21/2 pounds. Topazes are valuable but not as much as diamonds.

Not everything that looks like a diamond is actually a diamond. This is a picture of the Chalmers Topaz which is 5,899 carats and weights over 21/2 pounds. Topazes are valuable but not as much as diamonds.

How to Test if a Diamond is Real or Not

There are a number of tests that can help you tell if a diamond is real. These tests focus on the unique characteristics of diamonds, which are not found in other gems or in glass imitations.

The chief characteristics of diamonds tested by these methods are: 1) hardness 2) color and 3) refraction of light.

  • The Hardness Test - one of the easiest ways to determine if a stone is a diamond or simply looks like one is to test how hard it is. Real diamonds are one of the most hardest substances and cannot be cut or scratched by less hard substances. In fact, real diamonds will scratch most other surfaces while remaining intact.

    One way of testing the rock's hardness is to try to scratch a piece of glass such as the surface of a bottle or an old window. If the rock easily scratches the glass, it is probably a diamond, though it could also be a cubic zirconium. In some cases, a fake diamond made of glass can also scratch other glass if the "diamond" has particularly sharp edges, so this is not a fool proof method.

  • Black Light - This is one of the best tests but it will require you to buy a special light bulb that emits black light. Black lights emit long ultraviolet waves and alter the way we see things. For example, you may have seen the actors on CSI use black light to spot stains that would not otherwise be visible to the naked eye.

    You can also use black light to see what kinds of deposits the previous occupants of your hotel room have left on your bedspread. On second thought, it is best that you do not know.In the case of diamonds, you can use black light to determine if the stone is real or not. If it is made of glass, the fake diamond will not emit any color when you shine the black light on it. If it is a cubic zirconium, the rock will glow yellow. If it is a real diamond, the stone will give off a blue glow under a black light.

  • The Refraction Test - real diamonds have unique properties that tend to bend light in much the same way as when you put a stick in the water. The part of the stick below the waterline will seem detached from the upper portion above the water. In the case of diamonds, you can use the same principle to determine whether the stone is actually a diamond by drawing a straight line on a piece of paper and then placing the rock on top of the line. If you can see the line through the stone then it means that the stone is probably not a diamond but actually a piece of glass costume jewelry.
  • The Paper Test - This is a variation of the refraction test described above. It involves placing the diamond on top of a white piece of paper with small lettering on it, and then looking through the stone at the text below. If you can see the text through the diamond clearly and without distortion what you have is not a real diamond but most likely just a piece of glass. However if the text under the crystal is distorted, then it may be a diamond because diamonds bend the light in a particular way.
A diamond necklace on display at the Field Museum in Chicago

A diamond necklace on display at the Field Museum in Chicago

Real or Fake - Only a Jeweler Can Tell For Sure

It is important to remember that these tests are not precise and some fake diamonds are such good imitations that you may not be able to tell them apart. Similarly, don't be too quick to get rid of that diamond ring or necklace. Even if these tests suggest that it is not a diamond, only an expert can tell for sure. Jewellers and gemologists have a number of techniques that they use to determine if a diamond is real or not. They rely mainly on visual observations using a special magnifying glass which allows them to see the internal structure of the stone more clearly.

Comments

PETER LUMETTA from KENAI, ALAKSA on September 30, 2011:

There are two types of diamonds, natural and synthetic. Both are diamond one is made by nature and one is made by man. There are diamond simulants, which are anything that looks like a diamond but are not diamond. Simulants are what are reffered to as "fakes".

Peter Lumetta, G.G.