How to Tell if a Diamond is Fake or Real

One common issue that people have with diamonds is determining if it’s a fake or real diamond. Whether it’s a gift someone gave you, a diamond you found at a garage sale, or something that you inherited from family members, it’s always beneficial to know whether you have a fake or real diamond in your hands. For example, if it’s a stone that weighs 1 carat, the price could vary greatly. If it’s a fake diamond, it could be $800, if it’s a real diamond, you could be looking at a diamond that has a $10,000 value! Here are some tips and simple tests that you can do to tell a real diamond from a fake diamond. Be sure to always have an appraiser or a jeweler check for you if the diamond is real or fake. Never use these at home tests as your final determinant of the stone type. However, if you want to test a stone at home, you can use one of these simple tests as a starting point.

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The Sandpaper Test

This is an extremely easy test to do, all you need is some sandpaper. Since diamonds are one of the world’s hardest materials, they won’t be scratched at all by the rough surface of sandpaper. It will remain in perfect condition. However, if it’s some type of fake diamond (a popular one is cubic zirconium), then it will scratch up.


The Read-Through Test

The “read-through” test is exactly what it sounds like: a diamond authenticity test in which you attempt to read text through the diamond in question. Any diamond that is unmounted in a setting or piece of jewelry, also known as “loose” diamonds, qualify for this test. Simply turn the diamond upside down on a sheet of paper with plain black text on it, and look through the upturned diamond to read it. Natural diamonds are difficult, or even impossible, through which to read, while synthetic diamonds, like the cubic zirconia, will allow you to make out the letters and/or words printed on the page. The read-through test is an inexpensive, easy and time-efficient way to test your diamond’s authenticity at home and on your schedule.


The Sparkle Test

The way a stone reflects and refracts light is a good indication of its authenticity. Some professionals recommend doing what is referred to as an “at-home sparkle test,” to determine whether your precious gem is a natural diamond or one that was synthetically produced.

Basically, the at-home sparkle test is a visual inspection of the stone’s “behavior” in the light. A stone’s natural light refraction cannot be altered, even by the most skilled jewelry professional with the best equipment. Therefore, the light reflection/refraction, or the lack thereof, of a gem, is typically accurate.

Synthetic, or fake, stones, sparkle less than real, or natural, diamonds. The light refraction ability is lower in manufactured stones than in naturally-formed ones, which means they shine less brilliantly.

With light reflection, look for shades of gray. Synthetic stones, such as cubic zirconias, sparkle with more iridescent colors. Natural diamonds reflect light in more grayish hues. So, if yours is a stone of many colors, it’s probably synthetic.


Water Test

Here is another simple test that costs nothing to do. Get a glass and fill it three-quarters of the way with water. Carefully drop the loose stone into the glass of water. If the stone stinks, then you know it’s a real diamond. If it floats underneath, or at the surface of the water, then it’s a fake diamond. You will know that the diamond is real if it sinks because a real diamond has high density. Therefore, the water test determines if your stone matches this level of density.


How Using Heat Helps Determine a Diamond’s Authenticity

Natural diamonds are the strongest gemstones on the market. They can withstand any abuse we routinely inflict on them in our daily lives, including exposure to extreme heat for an extended period of time. That’s why some people will opt to perform a heating test on their loose diamonds. To properly conduct the test, expose a loose gemstone to an open, but controlled, flame, for about 30-45 seconds. Have a container with a wide opening filled with cool water nearby, and after the 30-45 second period, immediately put the gem into the water.

No manufactured gemstone can withstand such intense heat. Diamonds conduct heat well and diffuse it evenly throughout the stone. A word of caution before you administer this test on your loose diamonds: the extreme heat and sudden switch to the cool water WILL demolish any stone other than naturally-formed diamonds. Therefore, we beseech you to NOT attempt this test at home unless you are ok with the possibility that your diamond is synthetic and that it could be rendered worthless for jewelry after the test if it is a fake.

On the other hand, if it turns out that your loose diamond is real, you can rest assured that it can stand up to any torture through which you will put it with your unique lifestyle. You saw it with your own eyes, so you’ll enjoy and appreciate the gem that much more!


How to Differentiate Between a Diamond and a Moissanite

One of the most easily identified differences between moissanite stones and authentic diamonds is the color. Although both produce stones that are yellow, clear or green, those with naturally red, blue, brown, black or purple tinted stones (among other, rarer colors) are likely in the diamond category. The colors of natural diamonds are also more saturated, purer, than that of moissanite stones, which tend to appear to change colors as it disperses light throughout the gem.

Gemstone weight will also tell you whether you’re dealing with a diamond or moissanite. This is a harder quality to assess yourself, unless you happen to have professional jewel equipment at home, unless you’re especially sensitive to the weight differences of two similar objects. Moissanite stones weigh much less than their diamond counter parts, no matter how similar or exact their physical shape is.


How to Differentiate Between Diamonds and White Sapphires

Comparing white sapphire gemstones to natural diamonds is more difficult to do on your own. They are often very similar in size and color purity and saturation. They’re also similar in strength and solidity. In fact, the only stone harder than white sapphires are natural diamonds, and it’s a very tight race.

The differences lie deeper than the surface. For example, white sapphires form as corundum-based, hexagon-shaped crystal chunks, while carbon forms diamonds, in crystal pieces that are square, or cubed. The different shapes and minerals affect both gemstones’ facet shape and arrangement during development, creating different light reflection and refraction patterns.

Another difference between white sapphires and diamonds is purity. White sapphires are considered completely pure, period. Sapphires form in a variety of colors, but white ones have zero traces of other colors or murkiness, and tend to either be 100% white or a colored sapphire, which is rated according to its own class, separate from the white sapphire. Clear, colorless diamonds are rarely truly pure and perfect, and some flawless diamonds have traces of other colors.


Check The Setting and the Mount

If you have a diamond that is already placed in a ring, this is a good indicator of whether it’s fake or real. Carefully examine the type of setting and mount that is used. Since real diamonds have a large price tag, you won’t find them set in cheap metals. For instance, a real diamond will typically only be set in metals such as white gold, yellow gold, or platinum. In order to tell what type of setting it is, look inside the ring’s center for markings. For example, if you see the notes 10K, 14K, or 18K, those refer to the type of gold that is used. If you see the letters PT or Plat, those refer to the metal platinum. Also, if you see any numbers such as 585, 770, 900, or 950, those could indicate gold or platinum too. If you don’t see any of the above markings, but you see the letters “C.Z.,” that means that the gemstone is a cubic zirconia (a fake diamond).


Take it to a Gemologist

If you don’t have time to do any of the tests mentioned above, or if you don’t trust yourself and want a second opinion, the best thing to do would be to take your stone to a qualified gemologist. It’s important to understand that not all jewelers are gemologists! Most of the time, they are just salespeople, and don’t have any of the education that true gemologists do. If you do go to a jewelry store, simply ask if they have any qualified gemologists who can help you, or if they can refer you to a reputable gemologist in town who knows about diamonds.

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Expert Techniques

If you take your diamond to a qualified gemologist, they won’t just do the simple tests that you can do yourself at home. They have a few expert methods and tests that they will perform in order to determine whether the diamond is real or fake. These tests include:

Inspecting a diamond with a loupe - A loupe is a magnifying glass used for diamonds and gemstones. Professionals will look through the loupe for any blemishes and/or imperfections within the diamond. A fake diamond will typically not have inclusions, but a real diamond usually has small imperfections that are called inclusions.

Using “the Diamond Tester”, also known as the Thermal Conductivity Probe - This tool is used to determine the thermal conductivity of a gemstone. Real diamonds will disperse heat rapidly after being warmed, whereas fake diamonds will disperse heat at a slower rate.

High profile weighing - This is the use of a fine tuned scale for measuring small differences in weight.

Examining under a microscope - gemologists can use 1200x magnification on a power microscope to examine the stone in detail or conducting X-ray examinations

Assessing A Diamond

Hopefully, all of these tips mentioned above can guide you in determining whether a diamond is real or fake. Always be sure to have a certified gemologist or jeweler check if the diamond is real or fake. You can conduct tests at home, however; never rely on them to make any decisions about the diamond. The best way to prevent any doubt about your diamond or stone is to verify the authenticity of the stone before purchasing and only purchase from a place that you trust.