Your Trusted Diamond Jewelry Buyers
Benadato diamond buyers logo

How to Tell if a Diamond is Real

What’s on page?

Whether you’re buying, selling, or simply curious about the authenticity of a stone, knowing how to identify a genuine diamond is crucial.

With the proliferation of synthetic and imitation diamonds in the market, it’s essential to have the tools and knowledge to distinguish between real and fake diamonds. In this ultimate guide, we’ll explore various methods to help you determine if a diamond is genuine, including the water test, fog test, loupe test, UV light test, and professional appraisal.

1. The Loupe Test

Using a loupe (a small magnification device) is an effective way to determine if a diamond is real.

  • Begin by cleaning the diamond to ensure it is free of dirt and oil, then hold the loupe close to your eye and bring the diamond into focus. Genuine diamonds often have tiny natural imperfections called inclusions and blemishes, which appear as small spots or cracks.
  • Check the edges and facets; real diamonds have sharp, well-defined facets, unlike fake ones, which may have rounded edges. Some real diamonds also feature laser inscriptions on the girdle, including certification numbers.
  • If the diamond is set in jewelry, look for metal stamps indicating high-quality metals like gold or platinum, as these often accompany authentic diamonds.
  • Examining the diamond’s symmetry and cut quality can also be revealing, as real diamonds are precisely cut for maximum brilliance.

It’s important to note that the loupe test requires some knowledge and experience to accurately interpret the findings, and while it can provide valuable insights, it should be used in combination with other testing methods for the most reliable results.

how to tell if a diamond is real with a loupe

2. The Fog Test

The fog test is a simple and quick way to check if a diamond is real.

  • To perform this test, hold the diamond between two fingers and breathe on it, creating a light fog from your breath.
  • Observe how quickly the fog dissipates. Real diamonds disperse heat rapidly due to their high thermal conductivity, so the fog should clear up almost immediately, within a second or two. In contrast, fake diamonds, such as cubic zirconia, retain heat longer, causing the fog to linger for a few seconds.
  • For the most accurate results, ensure the diamond is clean before performing the test, as oils and dirt can affect the outcome. Additionally, conduct the test in a room with moderate humidity to avoid environmental factors influencing the results.

While the fog test is a useful preliminary method, it is not foolproof. For conclusive verification, combine it with other tests or consult a professional gemologist and consider performing a professional appraisal.

3. The UV Light Test

Another method for determining the authenticity of a diamond is the UV light test. When exposed to ultraviolet light, most genuine diamonds will emit a blue fluorescence. On the other hand, many fake diamonds will glow in different colors or not at all under UV light.

  • Ensure the diamond is clean before testing to avoid any interference from dirt or oils.
  • Place the diamond under a UV or black light in a dark room. Genuine diamonds often emit a blue glow under UV light, although the intensity and color can vary. Some diamonds may show little to no fluorescence, which is also normal for real diamonds. In contrast, many fake diamonds will not fluoresce under UV light or might emit a different color glow, like yellow, green, or white.

While the UV light test can be a helpful indicator, it should not be relied upon as the sole method for verifying a diamond’s authenticity.

4. Professional Appraisal

While at-home tests can offer preliminary insights, they lack the precision and certainty of a professional appraisal.

A professional appraisal is the most reliable method to determine if a diamond is real, as a certified gemologist or appraiser can provide a comprehensive evaluation using specialized equipment and expertise.

The process begins with a thorough inspection of the diamond, assessing its physical and optical properties. Professionals use tools such as loupes, microscopes, and spectrometers to examine the diamond’s inclusions, clarity, cut, color, and carat weight. They also perform advanced tests like thermal conductivity measurements to distinguish real diamonds from imitations.

A key advantage of a professional appraisal is the gemologist’s ability to detect synthetic diamonds and high-quality simulants that might pass basic at-home tests. Additionally, appraisers can verify the presence of laser inscriptions on the diamond’s girdle, which often include certification details from reputable gemological laboratories like GIA or AGS. This certification provides further assurance of the diamond’s authenticity and quality.


If you’re looking to buy or sell a diamond, it is crucial to verify its authenticity to ensure you receive the best possible value.

At Benadato we offer professional appraisal services, where our certified gemologists utilize advanced equipment to meticulously examine your diamond. This detailed evaluation not only confirms the diamond’s authenticity but also provides an accurate valuation, giving you confidence and peace of mind when selling your precious gemstone.

For a professional appraisal, contact us now:
1 888 625 0232

[email protected]

100 Fillmore St, 5th Floor Denver, CO 80206

<u><a style="color:#D2AA5C" href="">Yossi Benadato</a></u>

Yossi Benadato is the Co-Founder and one of the many diamond experts at Benadato. He is a second-generation diamond dealer who grew up in the industry in Israel

<u><a style="color:#D2AA5C" href="">Yossi Benadato</a></u>

Yossi Benadato is the Co-Founder and one of the many diamond experts at Benadato. He is a second-generation diamond dealer who grew up in the industry in Israel

What’s on page?
More Services for you
Sell Your Diamonds

Either its designer Engagement rings, Loose diamonds , or flashy diamond bracelets & necklaces sell your
jewelry to the most trusted buyer of Denver , Colorado.

We Pay Cash for Diamonds
Get in touch with us to sell any of your diamond pieces for the best value
We Pay Cash for Diamonds​