How to Determine if a Diamond is Fake?

One of the most important questions that bothers people when they see a diamond is whether its real or fake. In this article, Benjamin Khordipour G.D. will teach you everything you need to know to determine if a diamond is real from the comfort of your home.

Benjamin’s Tips to Determine if a Diamond is Fake

Authenticating a diamond isn’t rocket science, and there are many at-home techniques that you can employ to get a good idea if a stone is a real diamond or not. Even if a stone looks white and sparkles like a diamond, it can be many other things: moissanite, cubic zirconia, lab diamond, and glass.

Here’s my top tricks to use in order to know if you’re looking at a fake diamond.

Please Note: The following techniques are only guides and at-home suggestions for determining if a diamond is real. To authenticate a diamond with absolute certainty, you will need to have it tested professional.

1. Hot Breath Diamond Method

The Hot Breath Diamond Test is the easiest way to determine if a diamond is fake, and for that reason we placed it at the top of the list. That being said, the methods listed below are far more accurate.

Simply take the diamond and breathe on top of it. If the mist stays on the stone and takes over 2-3 seconds to disappear, it is quite likely that you’re looking at a fake diamond. If the mist and fog disappear quickly, it is possible that it’s a diamond.

Diamonds are extremely effective at conducting heat, which, along with their hardness, is why they are very suitable for industrial cutting processes. Fake materials like CZ and glass are actually quite poor conductors of heat, so a simple test will give you some idea as to whether you have a diamond or an imitation.

2. Newspaper Diamond Test

Like the previous diamond authentication test, the newspaper test is very easy to implement.

Lay the diamond on top of a newspaper with its table (the top flat part) facing the text (as shown in the photo) and then try to read the text through the diamond. If the letters show through the diamond as if it were glass, the stone is likely not a diamond.

What’s great about this trick is that it will also work on a diamond that is already set in jewelry. It may be a little hard to position it correctly, but with a little work you’ll usually be able line up the diamond so that you can see through it.

Expert Tip: If you see the text doubled right next to each other, the stone is probably moissanite and not a diamond.

3. Water and Diamond Test

This test is one of the least effective methods because it won’t eliminate most fakes, but the upside of this test is that it will eliminate the fakes with absolute certainty.

Fill a cup with room-temperature water and drop the loose stone into the cup. If the “gemstone” floats and doesn’t sink, it is undoubtedly a fake gemstone.

As you can imagine, many fake diamonds will also sink. It is for that reason that this technique doesn’t establish stones as diamonds, but merely eliminates fraudulent “diamonds” very quickly.

4. Diamond Heating Method

This test is good for eliminating fake diamonds, but should only be undertaken with extreme care. We recommend wearing heat-safe gloves to avoid injury. Please avoid this test altogether if you do not have a safe location to implement it.

Hold the loose diamond with prongs. With fireproof gloves, grip the stone tightly and expose it to a lighter or another flame for about 45 seconds. Drop the heated stone into a glass of cold water, and if the stone fractures or shatters, it is not a diamond. If no reaction is seen, then the diamond could be genuine.

Important Note: Do not try this method if the diamond is set into a mounting of any kind! Additionally, if the diamond is experiencing any form of existing structural compromises, this test may cause critical damage.

5. Find GIA Certification Number

Many diamonds will have been certified sometime in the past, and many of the certification companies will have lasered a certification number onto the side of the diamond. This even applies to antique diamonds that were certified at some later point.

Typically, you will need a jeweler’s loupe (magnifying glass) to see the numbers. The numbers are tiny, and you will need to search hard to find them. We recommend, though, just using your phone camera and putting it to x10 zoom. If you have zoom and lens attachments, that will make it even easier.

Make sure that you place the diamond or diamond ring on a flat and solid surface, and then aim your camera toward the girdle of the diamond.

Once you find the numbers, input those numbers into the certification database (like the GIA, for example), and you will know everything about your gemstone.

6. Look for Inclusions in Diamond

Almost all real diamonds have natural inclusions, and although the inclusions aren’t desirable, per se, in the diamond, they are a fantastic way to determine the authenticity of the diamond.

Before beginning ensure that you clean the outside of the diamond very well. Once clean, take a jeweler’s loupe (or use extreme-zoom with your phone) and search for inclusions. If you notice black dots, white dots, lines, or clouds inside the diamond, you will know that the gemstone might actually be a real diamond.

If you don’t see any inclusions, the “diamond” could either be a high-quality genuine diamond or a lab-grown diamond.

Expert Tip: If you see “bubble-like” inclusions inside the gem, it is without a doubt not a diamond. Additionally, if you see facets appearing doubled under a loupe, it is not a real natural diamond.

7. Use a Commercial Diamond Tester

Although the cheap diamond testers are far from perfect, they will actually work to eliminate many of the fake diamonds. We recommend using them even though the results are far from definitive.

A diamond tester will cost approximately $25 or so, and they are lots of fun. Link on Amazon.

Just be warned that these cheap testers will give false positives and false negatives, and will not be able to determine many different simulants and lab-grown diamonds.

8. Authenticate the Jewelry

A great way to authenticate a diamond is by authenticating the mounting that the diamond is sitting inside. If the mounting has provenance, there is a good chance that the diamond inside shares its story.

To learn how to authenticate vintage jewelry or designer jewelry, click here to read our full guide.

9. Show the Diamond to an Expert Jeweler

If all the above fails or doesn’t give you definitive results, bringing the diamond to an expert jeweler is the best option.

An expert jeweler will have professional equipment and be able to give you a definitive opinion on the status of the stone. He’ll be able to tell you if the stone is a diamond, lab-grown diamond, CZ, or moissanite.

Finding a Reliable Jeweler to Examine Diamond

As you can imagine, not all jewelers will be able to determine with complete accuracy if a diamond is genuine or not.

Here’s our advice on how to find a jeweler who can examine your diamond:

• Get advice from friends and family of jewelers that they trust.
• Check Google Reviews, Yelp, and BBB for reviews on your diamond seller.
• Ask for certifications (that contain diamond inclusion maps) and appraisals.

Different Types of Fake Diamonds

There are many options for fake diamonds. Here are the most common culprits: cubic zirconia (CZ), lab-grown diamonds (read our full opinion on lab-grown diamonds), moissanite, white sapphire, glass, and synthetic rutile.

How to Know if You’re Buying a Real Diamond?

As a buyer, there are a few large warnings that should trigger your suspicion. These warnings won’t tell you that the diamond is fake but rather should spur you to investigate.

• A seller that doesn’t have solid reviews and a solid reputation
• If a diamond is valued at a price that seems too good to be true, it almost certainly will be. Even assuming it isn’t fake and appears to be of good color and clarity, a suspiciously low price will often mean the diamond is stolen, which brings more problems than you’ll ever want to encounter.
• Lack of documentation and certifications
• A seller who is pushing too hard
• No return policy

Either way, diamond values are easily searchable on the internet, so as long as you can establish the 4Cs of the stone, you can quickly assess the approximate value.

If it is significantly lower than the going rate, walk away.

Talk to an Expert

Provenance is a great way to know if your diamond is real, but if it isn’t available, a certificate of appraisal is the next best thing. If all else fails, the tests above may help to eliminate some doubts, but a professional assessment will always be the ultimate way to check if your diamond is natural or imitation.