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Is Your Diamond Real or Fake? 10 DIY Tests to Find Out

December 25th, 2023

A woman wearing a diamond tennis bracelet places her hand on her chest.

In a world where counterfeit gems occasionally make their way into the market, it's crucial for diamond owners to have the tools and knowledge to verify the authenticity of their cherished jewels. Whether you're a seasoned collector, a first-time buyer, or simply someone who wants to ensure the value of their diamond investment, these tests will prove invaluable. Our experts here at Rogers Jewelry Co. understand the importance of trust and transparency in the diamond industry, and we're here to empower you with 10 methods to distinguish real diamonds from imitations, ultimately safeguarding your investment and preserving the beauty and allure of your treasured gemstones.

Water Test

A quick and simple method to conduct when assessing the authenticity of loose diamonds is the water test. To perform this test, fill a glass with water and gently drop the diamond into the glass. If the diamond sinks to the bottom, it is more likely to be a genuine diamond, as real diamonds have a higher density than water. Conversely, if the diamond floats, it may be an indication that the gem is not authentic. While this test can offer a preliminary clue, it's important to note that it is not foolproof and should be used in conjunction with other methods for a more accurate assessment of a diamond's authenticity.

Fog Test

To test a diamond set within a piece of jewelry, the fog test is ideal for a straightforward result. To perform this test, simply use your breath to fog up the surface of the gem, much like fogging a mirror. If the fog on the diamond's surface persists for three seconds or more, it may suggest that the diamond is likely fake. Real diamonds have exceptional heat-conducting properties, making it highly unlikely for them to fog up for an extended period. However, it's crucial to ensure the diamond is free from any oils or residues prior to conducting this test, as these substances can affect the accuracy.

a woman in a blue formal dress and wearing dramatic diamond earrings looks in the mirror.

Magnifying Glass Test

Essential to any evaluation, using a magnifying glass, or preferably a jeweler's loupe, is a crucial step in evaluating the authenticity of your diamond and assessing its quality. When inspecting a diamond, look for any imperfections, known as inclusions or blemishes, within the stone. These imperfections are natural occurrences in most genuine diamonds and are formed during the diamond's crystallization process. Therefore, if your magnified examination reveals a complete absence of any inclusions or blemishes, it might be an indicator that the diamond is not genuine. However, it's important to note that the absence of imperfections alone should not be the sole basis for determining a diamond's authenticity, as high-quality, flawless diamonds do exist.

Black Light Test

As a highly effective method for testing the authenticity of diamonds, the black light test reveals a distinctive and characteristic reaction. When a genuine diamond is exposed to ultraviolet light from a black light source, it typically emits a strong blue fluorescence. A striking blue glow is a unique property of many diamonds and serves as a strong indicator of their authenticity. This phenomenon occurs due to the presence of trace elements like boron within the diamond's crystal structure. However, it's important to note that not all diamonds exhibit this fluorescence, and the intensity of the blue glow can vary from one diamond to another.

Fire Test

Using drastic temperature fluctuations to test the authenticity of a diamond involves subjecting the gem to extreme thermal stress. This method can be risky, as it may permanently damage the diamond, especially if it is fake. To perform this test, one would use a lighter to heat the diamond for approximately 30 to 45 seconds and then immediately drop it into a glass of ice water. The rapid change in temperature can cause a fake diamond to shatter. However, it's essential to exercise extreme caution when attempting this test, as it poses a significant risk to both the diamond and the person conducting the test.

A pear-shaped diamond pendant against a white background.

Newspaper Test

For a non-invasive method that can offer some insights into the gem's authenticity, the newspaper test is useful. To perform this test, you can lay the diamond top-down on a piece of newspaper and examine it closely. If you find that you can easily read the text through the diamond, it may be an indication that the gem is a clear quartz or glass imitation. Genuine diamonds, on the other hand, possess a high refractive index, which causes them to bend light significantly. As a result, it becomes very challenging to see through a real diamond, making the newspaper text blurry or nearly impossible to read.

Mirror Test

Although it carries a high risk of damage, the mirror test is another test that can be valuable in determining if your diamond is real. To perform this test, attempt to scratch the diamond in question against a mirror. If the diamond successfully scratches the mirror, it might indicate the gem's authenticity, as diamonds are one of the hardest substances known and can scratch most materials. If the gem ends up with a scratch, it is likely that the diamond is fake. However, it's important to note that this test can cause severe damage to both the mirror and the diamond. 

Sparkle Test

Assessing the sparkle of a diamond is a practical and non-invasive way to evaluate its authenticity. Simply place the diamond under a lamp or a direct light source and observe its sparkle. Genuine diamonds are renowned for their exceptional brilliance and fire. Real diamonds will typically emit a dazzling white light when exposed to light. In contrast, imitation gems may appear dull and lack the remarkable sparkle that is synonymous with authentic diamonds. Cubic zirconia, for example, often produces a noticeable rainbow effect, whereas genuine diamonds exhibit a captivating and colorless brilliance.

A pair of diamond stud earrings with a matching pendant in a gift box.

Weight Test

Comparing the weight of your diamond to known true diamonds of similar cuts and carats can be a valuable tool in evaluating its authenticity. Genuine diamonds have a consistent density and weight that is characteristic of their mineral composition. Therefore, if your diamond significantly deviates from the expected weight range for its size and cut, it may raise suspicions about its authenticity. Fake diamonds, which are often made from materials like cubic zirconia or moissanite, tend to have a higher density and can weigh significantly more than real diamonds of the same size.

Trust a Professional to Evaluate Your Diamonds

Taking your diamond to a professional jeweler is unquestionably the most reliable and secure method to verify its authenticity. Jewelers undergo extensive training and have years of experience in working with precious gemstones, including diamonds. They have access to a wide array of specialized tools and equipment specifically designed for diamond testing, ensuring accurate and non-destructive assessments. They can also detect any potential treatments or enhancements that might affect the diamond's value. When it comes to such valuable investments, the expertise of a professional jeweler is invaluable in providing peace of mind and ensuring the authenticity of your cherished diamond.

a woman wearing a diamond floral bracelet touches her long, wavy hair.

Find Natural Diamond Jewelry at Rogers Jewelry Co.

At Rogers Jewelry Co., we take pride in offering an exquisite selection of natural diamond jewelry that reflects timeless elegance and enduring beauty. Our commitment to providing you with the finest quality diamonds is unwavering, and our expert jewelers are dedicated to helping you find the perfect piece to celebrate life's special moments. With locations in Fresno, Modesto, Elk Grove, Folsom, Reno, San Luis Obispo, and Bakersfield, Rogers Jewelry Co. is conveniently located across California and Nevada to serve you. Additionally, our custom design service allows you to bring your unique vision to life, creating a one-of-a-kind piece that speaks to your personal style and sentiments. Contact us today for more information on our products and services.