How Can You Tell If A Diamond Is Real?

Have you ever asked yourself: would I be able to tell whether or not a diamond was real? Or maybe you received jewels from a relative and you want to be able to discern for yourself without having to see an expert. It might be important for you to do the first round of testing to see if it's even worth going to a jeweler to find out the value of the piece.  

There are a number of home tests that can be completed to figure out whether a diamond may be real or fake. 

One of the most important aspects is knowing a diamond’s structure, so we know what components to look for. Sometimes, other stones can be mistaken for diamonds, which are highlighted in this article. Keep reading to activate your inner gemologist and learn how to test a diamond at home to find out whether or not it's genuine.

How to Test a Diamond at Home

1. Diamond Water Test

The first test we want to talk about involves water. This may be the easiest test, but it requires that we have a loose gemstone. Since diamonds have a high density, they will naturally sink when placed into a cup of water. If the stone happens to float, that means it is indeed fake. 

2. Diamond Fog Test

Here is another at-home test that is simple and all we need is the stone, or ring, and our breath. Take the stone either in between your fingers or you could even pick it up with tweezers. Take a big breath, as if you are trying to fog up a mirror. As you breathe onto the stone, you are looking to see if the stone clears up or remains cloudy. 

The moisture and heat in our breath create a fog, and if the stone is in fact a diamond, the diamond will disperse the heat very quickly. If the stone is not a diamond, it will hold the heat in and remain cloudy for a longer period of time. 

3. Diamond Newspaper Test

Yes, you read that right! 

We can use newspapers to tell if a diamond is real, but we will need it as a loose gem. This is to test the stone’s refractivity (the way it bends light). If we can read or see any words from the newspaper through the stone, it is not a diamond. When the diamond is real, the light will bend in many directions; therefore, we would not be able to read anything through the stone. 

If a newspaper is not available, we can take a plain white piece of paper and draw a small dot with a pen. If we can see the dot at all, the stone is not a diamond. 

4. Diamond Light Test

This is another easy, and effective test we can do by ourselves at home. When we take a diamond and look at it under any kind of light, we will see it shine and sparkle in white and sometimes gray-ish light. If we look at a stone under a lamp and notice a colorful rainbow, that means the stone is not a diamond. 

5. Diamond Under Magnifying Glass Test

If we have a magnifying glass, we can use it to get a closer look at the stone to determine its integrity as a diamond. As we look at the stone through the magnifying glass, we should be able to see inclusions, or tiny fractures, throughout the stone. If there are none, and the stone looks perfect, it is not a diamond. 

Although there are flawless diamonds, they are usually created in labs or are highly valuable. But to note, not all lab-created diamonds will be flawless. 

6. Black Light Diamond Test

After the lights are turned off, hold the diamond in front of the black light. Diamonds usually reveal a blue fluorescence, whereas other stones will give off a green, yellow, or gray hue. 

We must mention that not all real diamonds will give off a blue hue—so use this home test option at discretion!

What Other Stones Closely Resemble Diamonds?

There are four other stones that can be mistaken as diamonds and we want to review them now. That way, we will have this information in our back pocket in case it’s ever needed. 

White Topaz

Although diamonds are much stronger than topaz, this stone has been falsely labeled as a diamond before. When looking at a topaz, it may reveal scratches that are uncharacteristic of a diamond's hardiness. This stone can be either a tinted yellow, red, brown, or pale grey and even colorless, or white. 


This stone can be the most challenging to tell apart from a diamond. Oftentimes, an expert may be required. This stone does have a sparkle to it but when it reflects light, we would be able to see a rainbow of colors. 

Experts will use an electrical conductivity test to determine its true type. A thermal conductivity test cannot be used because moissanite has a similar thermal conductivity as diamonds. 

White Sapphires

When we envision sapphires, it's usually in their blue hue, yet this stone also comes in white and a wide range of other colors. A white sapphire will look clear to the naked eye, but as we get closer, we may see more scratches as this stone is not as strong as a diamond. A white sapphire will not have the same sparkle and brilliance as a diamond. 

Cubic Zirconia

Since 1976, cubic zirconia has been mass-produced and is one of the easier stones to conduct a home test on. This stone scratches easily and does not have the same sparkle and shine as a diamond does. We could use the sparkle test to see this stone reflecting an orange-tinted light. With a closer look, cubic zirconia will not have any inclusions. While at the same time, this stone weighs more than a diamond and would pass the at-home water test. 

Are Diamond Tests at Home Trustworthy?

Even though these at-home tests are a great place to start, there are a few caveats on their reliability. 

Let’s take moissanite for instance. This is the most challenging stone to determine if it's a diamond or not. The only true way to tell is through an electrical conductivity test through a jeweler or gemologist. 

It is also easier to do the home test with a loose gem and oftentimes, what we are testing is already in a setting of some kind. If the diamond has already been mounted, it may be hiding flaws or clues as to its authenticity. The mounting also makes it easier for that stone to reflect light, regardless if it's a diamond or not. 

Home tests are the perfect first step at doing our own due diligence. It can also be an emotional experience determining whether a stone is a diamond or not. For example, say a relative’s heirloom was received and one of the rings may be sentimental and used as an engagement ring. 

We want to make sure the integrity is intact with such a meaningful and emotional decision. In instances like this, it is best to have an expert provide final confirmation. 

How Do Experts Test Diamonds?

We feel it’s essential to briefly touch on what the experience may be like if we go to a jeweler or gemologist to test the authenticity of a stone. Jewelers and gemologists have access to a microscope, or what they call a loupe. It’s used to look for inclusions and imperfections in the stone. Most fake diamonds will appear to be perfect when looking under a microscope. 

Diamond Tester or Thermal Conductivity

This is a meter that is used to determine how a stone disperses heat. The tip of the meter is placed on the stone and it will show how heat passes through the stone. A diamond is able to disperse heat through it rapidly; whereas, cubic zirconia, for instance, would hold the heat for a period of time. As we mentioned earlier, moissanite disperses heat similar to diamonds, so that is the only cautionary aspect of this test. This type of diamond tester can be purchased on the market by anyone. 

Electrical Conductivity

Just like thermal conductivity, electrical conductivity is a similar process with electricity being used instead. This test is reliable when it comes to how difficult it can be to test for moissanite. Diamonds will emit signs of conductivity being present, where stones such as cubic zirconia and moissanite will not. Similar to the thermal conductivity test, this unit can also be purchased on the market by anyone. 

X-Ray Machine

In order for the internal part of a gem to be viewed, it will need to be looked at in an x-ray machine. This will determine whether the stone has a radiolucent molecular structure, meaning the stone will be transparent in the x-ray machine, or a radiopaque molecular structure, where the stone will not be transparent in the machine. Some stones like cubic zirconia are radiopaque; whereas, diamonds are radiolucent. 

Eterneva Cremation Diamonds

If you are searching for jewelry that can help commemorate the life of your loved ones, Eterneva is here for you. Our cremation diamonds are real diamonds that are made through an intricate seven-step process. We are here every step of the way to ensure you receive a diamond as brilliant as the life of your loved one.

In Conclusion

With the number of at-home test options, this can be a perfect place to start to see if your gem is a diamond or perhaps another stone. In this article, we shared six of the most popular ways to test for diamonds at home. 

We have highlighted some key pieces of information you will need, such as what to look for if your stone is a white topaz, cubic zirconia, white sapphire, or moissanite. 

At the end of the day, an expert or gemologist will be the one to give a final confirmation as to your stone’s full value. They simply have more advanced technology plus experience that will determine any stone’s authenticity. If anything, testing your gem will become a fun science experiment and bring you back to your childhood days of exploration! 


How to Tell if a Diamond is Real or Fake | Diamonds 

5 Ways To Spot A Fake Diamond | Business Insider 

How Do Diamond Testers Work and Are They Reliable? | Jewelry Notes