Real Diamonds vs Imposters: A Complete Guide To Figuring Out If You Have A Real Diamond Or A Good Imposter

There are a lot of different gems that a person may have in their jewelry box, but not all of them may be what you think they are. They may be a real diamond, but they may also be a moissanite or a cubic zirconia. Whether you have loose stones or stones already set in jewelry, you definitely need to know if the stones are real diamonds or something else.
There are a number of different tests (professional and at-home) that can be conducted to figure out if you have a real one on your hands. If it is not real, we also have some information in this article to help you to figure out what type of stone it may be.

Tests The Experts Will Conduct

It is not your only option but going to a professional may be the best idea in order to figure out what type of stone you have. Make sure that the professional that you go to see has a Graduate Gemologist degree so that you know they have the knowledge and skills necessary to give you an answer.
There are a few different tests that a professional will use in order to give you the answers you are looking for.

Employing The Use of A Loupe

A loupe is a special magnifying glass that these professionals utilize in order to examine diamonds, jewelry, and other gemstones. There are particular imperfections, known as inclusions, that a real diamond will have. A fake (or synthetic) diamond is going to be made with a certain level of perfection.

Determining Authenticity Through Weight

A true diamond is going to be lighter in weight than something like a cubic zirconia. The reason you will want to have it weighed by a professional is that they are going to have the proper scale needed in order to weigh in carats. These are special scales that are going to be properly calibrated and the professional will know what is to be expected from a real diamond. They will also have other stones (like cubic zirconia) in order to compare to. Though the diamond will be lighter, it will be my small increments that an average scale is not going to be able to detect.

Testing The Electricity Conductivity Of The Stone

A jeweler or gemologist will have the tools and skills necessary to conduct this test. Genuine diamonds conduct electricity much better than other gems, including the synthetic moissanite. The moissanite stone has some characteristics that can closely mimic a diamond (i.e. thermal conductivity). This test will give the gemologist or jeweler a clear answer as to whether the stone is a real diamond or a fake.

Using A Diamond Tester (Thermal Conductivity)

A diamond tester is a thermal conductivity probe and it measures the thermal conductivity of a gemstone. Diamonds, when heated, conduct heat well and they disperse that heat at a rapid rate. An imposter gem is going to disperse that heat at a much slower rate.
The problem arises if the imposter gem is a moissanite because these stones disperse the heat at a rate that is close to, if not equal to, that of a genuine diamond. Though this is a tool used by professionals, you can buy one yourself on sites like Amazon if you wanted to test the stone yourself.

Is It A Diamond Or A Synthetic Moissanite?

Moissanites are becoming increasingly present within the market and these stones can very closely resemble diamonds. There are certain tests that professionals can perform that will give you the definitive answer as to whether it is a moissanite or a real diamond.

An Examination Via X-Ray

A high-tech diamond lab will be able to perform an x-ray exam on the stone. This test will reveal the molecular structure to determine whether the particular stone is radiolucent or radiopaque in structure. Fake stones (like moissanite) are going to be radiopaque, while genuine diamonds are radiolucent.

Under A Microscope

A microscope is going to show the inclusions and difference that distinguish diamonds from moissanite stones. These microscopes magnify at a power of around 1200x and a gemologist or jeweler is going to be able to identify the minute difference under the microscope.

The Scratch Test

Before improvement in the technology that was available to professionals, the scratch test was a common test that people would utilize. The stone would be used to scratch a mirror to see if the mirror was damaged by the stone or if the stone obtained damaged.
This may have been a reliable test in the past, synthetic stones are made in labs so that they are much stronger and more durable. Because of the improved quality of these man-made stones, the scratch test is no longer a reliable means to test whether a stone is a real diamond or not.

Tests That You Can Do At Home

Though a professional may be your best bet in determining the type of stone that you have, there are tests that can be done in your home. These tests are going to give you a simple answer as to whether the stone is a genuine diamond or if it is something else. If these tests are conducted and the stone is determined to be a fake, you will need to employ the expertise of a professional to determine what type of stone it is.

Examine The Mount And The Setting Itself

For a stone that is already set into a piece of jewelry, there are certain things that you can look for. First of all, a real diamond is an expensive truly precious stone, and it is only going to be set into jewelry of a certain quality and made of certain materials. These materials include things like white gold, platinum, and yellow gold. It will be set into a setting such as a side-stone setting or a halo setting.
You can further investigate the piece of jewelry by checking for certain engravings on the piece. For example, 10K, 14K, or 18K will be engraved on a piece of true gold. You will find a PT or Plat engraved into a piece of jewelry that is made of platinum. Also, 585, 750, 900, and 950 are engravings that are used on pieces that are made of platinum and gold.
C.Z. means exactly what you think it means and the gem is not real at all, it’s a cubic zirconia.

A Simple Glass Of Water

There is a quite simple water test that you can do that will help you to figure out if the stone is a diamond or an imposter. A true diamond is going to sink to the bottom of a regular glass of drinking water because of the density of a diamond. If the stone floats just under the surface, it’s an imposter.

The Heat Test

For this test, you will need a drinking glass with cold water in it, a lighter, and heat resistant gloves (or something that will allow you to hold the stone and not burn yourself). Due to the strength of diamonds, they are not fazed by high temperatures.
While wearing your heat resistant gloves (or whatever you have to hold the stone, so you can heat it up without injury), heat the stone up with the lighter for approximately 40 seconds. Once heated, immediately drop the stone into the cold water.
If the stone is real, this temperature shock will not affect the stone at all. It is not going to crack it or shatter it in any way. A fake is going to take on some sort of damage due to the extreme temperature shock.
This is just like if you took a glass pan out of the oven and immediately tried to wash it, it would crack or shatter because of the temperature change. Heat causes things to expand, while cold will cause contraction. These extreme reactions are what will cause a stone of lesser strength and quality to crack or shatter.

The Fog Test

For this test, you will just need to puff your breath right on the stone. Your breath will produce a fog, just like when you puff your breath on a window. An authentic diamond is going to cause the fog to dissipate almost immediately. If the dissipation takes a few seconds, it is an imposter.
The heat conductivity of diamonds causes this immediate dissipation of the fog.

Using An Ultra-Violet Light

This is one of those tests that is not going to provide a definitive answer for you. Most real diamonds (not all of them) give off a bluish glow under a UV-light. There are some real ones that are not going to give off this glow. This is why this test is not highly recommended for clear results.

Measuring The Refractivity At-Home

One of the things that diamonds are known for is their sparkling quality, also known as brilliance. They have an innate quality that allows them to be able to bend and refract light in such a way that makes them sparkle in a way that other gems will not be able to. Light hits the angled lower surfaces (also known as pavilions) and that light is bent up through the top, flat surface (also known as the table).
Imposter diamonds and other stones (like cubic zirconia and moissanite) are not able to sparkle like a genuine diamond. They do not have the brilliance (sparkle) that diamonds are able to produce.
You can test this refractivity at home via a couple of simple tests.

The Read-Through Test

All you will need for this test is a piece of newspaper with a lot of writing on it. Make sure that the area in which you are doing the test is well lit and that there are no shadows being cast over the stone. This test can only be conducted on loose stones. Those set in a piece of jewelry will need to go through different testing.
Place the stone on the piece of newspaper with the table (flat, top surface) side down. A fake stone will refract the light in straight lines which will allow you to read the letters on the page. A real diamond bends light so well that you will not be able to read the letters.

An Alternative To The Read-Through Test

If you do not have a piece of newspaper handy, you can utilize the dot test. All you need is a plain, white sheet of paper. Draw, with a pen, a small dot on the piece of paper. Conduct the test just as you would with the newspaper test, and if you can see the dot the stone is not a real diamond.
Because of the refractive qualities of diamonds, you will not be able to see the dot as you look down through the pointed end of the stone. Diamonds do not allow light to travel through in a straight line, like other gems and synthetic stones.

Testing Reflectivity At Home

As refractivity refers to the way in which light is bent and bounces, reflectivity refers to the quality and amount of light that reflects through the gem. As brilliance (refractivity) deals with sparkle, reflectivity deals with, both, brilliance (white light) and fire (colored light) that the diamond produces.
This is measured through the sparkle test.

The Sparkle Test

All you need to do for this test is to hold the stone underneath an everyday lamp. You are going to be looking at the way in which the stone being tested is reflecting the light from the lamp. A real diamond is going to reflect, both, white and colored light in a wonderful way.
The difference between a real diamond and an imposter is going to be drastic when it comes to this test. Diamonds generate beautiful reflections of light that are going to far “outshine” other types of stones. So much so that the difference is clear.

What The Stone May Be (If It Isn’t A Real Diamond)?

If you find that you have a stone that looks like a diamond but has been found to be a fake, there are some ways that you can figure out what it actually is. Different stones have different characteristics and qualities that can be identified through many of these tests.

Cubic Zirconia

These stones are some of the easiest ones to differentiate from a diamond. Many have found that the sparkle test is the best way to identify a cubic zirconia because they will reflect an orange colored light.
Other qualities that will set them apart from diamonds is that they weigh more, and they do not have the natural imperfections that a diamond has. These imperfections on a diamond may be visible to the naked eye, but you may need a professional to examine them.

White Topaz

These look similar to diamonds, but their qualities and characteristics are not. They are nowhere near as strong as diamonds as the material is easily scratched or damaged. White topaz stones will have scratches on the surface, where diamonds won’t because of how strong and durable they are.

White Sapphire

Many are familiar with blue sapphires, but there are also white as well. They are often used in place of diamonds, but they do not sparkle like a diamond (not even close). Another characteristic of white sapphires is that their color seems to be blurry in comparison to a diamond. What this means is that a white sapphire is not going to have light and dark parts like a diamond will.


Many believe that this particular stone is one of the best imposters. Moissanite is a synthetic gemstone that is going to require the owner to employ the services of a professional jeweler or gemologist to determine the composition.
It is likely that the professional is going to use an electricity conductivity test in order to determine whether it is a diamond or a moissanite. This is the best test to conduct in order to obtain a definitive answer because moissanite resembles genuine diamonds in a lot of different ways.

Synthetic Diamonds

Synthetic diamonds are those that are created in a lab. These are incredibly similar to natural diamonds, down to the molecular composition. Due to their similarities, if you believe that you have a synthetic diamond, you should take it into a professional.
They are going to employ the conductivity test and examine the gem under a microscope. It is important to know if the diamond is synthetic or natural because it can make a big difference if you decide to sell the stone or if you plan on insuring it.

In Conclusion

There are a lot of ways to tell if a diamond is real or fake, but none of the at-home tests are 100%. It is always best to go into a professional because they are going to be able to recognize the minute differences and you can leave their office knowing, for sure, what type of stone you have.
If you are looking into buying a stone, you are going to want to investigate the buyer in which you are doing business with. You will also want to check and make sure that any diamond that you are looking to buy comes with an HRD or GIA certificate. Also, double check to make sure that the certificate matches the stone.
Ask all the questions that you may have and don’t pay for anything that you are unsure of.