How to Tell if a Diamond is Real (11 easy ways)

For countless individuals worldwide, buying a diamond isn’t just a purchase, it’s an emotional journey.

It often symbolizes monumental moments, from engagements to anniversaries, or even an heirloom passed down through generations.

how to tell if a diamond is real
how to tell if a diamond is real

Hence, the significance of knowing the authenticity of the stone you own or plan to buy cannot be overstated.

These days, the market is flooded with gemstones that bear an uncanny resemblance to diamonds. Stones like white topaz, white sapphire, and white zircon can easily deceive an untrained eye.

It’s no wonder that the question, “How to tell if a diamond is real?” is one of the most frequently asked by potential buyers and inheritors alike.

While the gold standard for determining a diamond’s authenticity is always a certified gemologist’s expertise, there are several home tests that can provide quick insights.

In this comprehensive guide, we’ll delve into these methods, ensuring you’re well-equipped to tell a genuine diamond from a dud.

How to Know if Your Diamond is Real with Home Testing Methods

Diamonds have unique physical properties that set them apart from other gemstones. By understanding these properties and leveraging simple home tests, you can quickly gauge the authenticity of your diamond.

Keep in mind, however, that while these methods can offer insights, they aren’t foolproof. Let’s explore some of these home testing methods:

  • Visual Inspection: Often, the simplest way to start. Using a magnifying glass, look for imperfections inside the diamond. Genuine diamonds often have tiny flaws called inclusions. If it’s spotlessly clear, it might be a sign of a synthetic or fake stone.
  • Touch Test: Real diamonds are effective heat conductors. If you breathe on a diamond, the fog created by your breath should dissipate almost immediately.
  • Transparency Test: When placed upside down on a newspaper, a real diamond shouldn’t magnify the text. If you can read the newspaper through the diamond, it might not be genuine.
  • Water Test: A real diamond has high density. If you drop it in a glass of water, it should sink to the bottom.

Under ultraviolet light, some diamonds will exhibit blue fluorescence. While not all real diamonds show this, a lack of fluorescence doesn’t necessarily mean it’s fake.

Quick Home Tests for Diamond Authenticity

Test MethodReal Diamond BehaviorFake Diamond Behavior
Visual InspectionShows inclusionsOften flawless
Touch TestFog dissipates quicklyFog lingers
Transparency TestCan’t read text through itText is readable
Water TestSinks to the bottomMight float
UV Light TestMight show blue fluorescenceVaries; might not fluoresce

It’s essential to approach these tests with a degree of skepticism. Many of them rely on properties that, while common in diamonds, can also be found in other stones or high-quality fakes. For absolute certainty, always seek a professional opinion.

In 2018, a woman in New York purchased what she believed was a diamond engagement ring worth over $5,000. Upon a friend’s suggestion, she conducted a few home tests.

The stone failed the fog and transparency tests. An eventual appraisal by a gemologist revealed it to be a high-quality cubic zirconia.

While she was initially devastated, her proactive approach saved her from further heartbreak down the line.

While home tests are valuable tools, the expertise of a certified gemologist remains unmatched in determining a diamond’s authenticity.

The Fog Test To Determining If Your Diamond Is Real

The Fog Test To Determining If Your Diamond Is Real
The Fog Test To Determining If Your Diamond Is Real

One of the most straightforward tests to determine if a diamond is genuine is the Fog Test. This test leverages the diamond’s unique thermal conductivity properties.

Here’s how you can perform it:

Steps to Conduct the Fog Test:

  1. Clean the Stone: Ensure the stone is clean. Any oil or dirt on its surface can interfere with the results.
  2. Hold the Diamond: Take the diamond between your fingers and bring it close to your mouth.
  3. Breathe Onto the Diamond: Exhale onto the diamond, similar to how you’d fog up a mirror or a windowpane.
  4. Observe the Results: A real diamond will disperse the heat from your breath instantly, causing the fog to disappear in a split second. In contrast, a fake diamond will retain the fog for a longer duration.

Why Does This Work?

Diamonds are excellent conductors of heat. This means they have the ability to disperse heat rapidly. When you breathe on a genuine diamond, the warmth from your breath doesn’t stay on its surface for long, making the fog evaporate almost immediately.

On the other hand, most fake diamonds do not have the same heat dispersion properties, causing them to stay foggy.

Quote: “The diamond’s allure lies not just in its sparkle, but in its resilience. Just like its properties, its authenticity endures.” – Renowned Jeweler, Marc Bennet

However, there’s a caveat. Some other gemstones, or high-quality imitation diamonds, might exhibit similar heat dispersion properties.

Hence, while the fog test is a quick and easy method, it shouldn’t be the sole determinant of a diamond’s authenticity.

The Fog Test is a quick method to gauge a diamond’s authenticity, but it’s crucial to couple it with other tests for a more conclusive result.

Water Testing Your Diamond

The water test is another simple yet effective method to check a diamond’s authenticity, capitalizing on the gem’s density.

Diamonds, being one of the densest gemstones, will sink in water, whereas many of their imitations tend to float or sink slowly.

Steps to Conduct the Water Test:

  1. Get a Glass: Use a transparent glass or bowl and fill it three-quarters of the way with water.
  2. Gently Drop the Diamond: Carefully drop the diamond or the diamond-set jewelry piece into the glass.
  3. Observe the Results: A genuine diamond, due to its high density, will sink to the bottom almost instantly. If the stone floats or takes time to sink, it might not be a real diamond.

Why Does This Work?

The concept behind this test is the principle of density. Diamonds have a density of around 3.5 grams per cubic centimeter.

This high density ensures that they sink rapidly in water. Most fake diamonds, like cubic zirconia or glass, have a lower density, causing them to behave differently when submerged.

Quote: “Just as a diamond sinks in water, its value and authenticity remain unshaken in the jewelry market.” – Gemologist, Linda Torres

While the water test is a handy tool, it’s essential to remember that other dense gemstones might also sink quickly.

So, like all home tests, the water test should be used in conjunction with other methods for a more comprehensive analysis.

The Water Test can offer quick insights into your diamond’s genuineness, but always couple it with other methods for an all-encompassing evaluation.

How to Tell if Your Diamond is Real Using a Magnifying Glass

How to Tell if Your Diamond is Real Using a Magnifying Glass
How to Tell if Your Diamond is Real Using a Magnifying Glass

A magnifying glass, an essential tool for any gem enthusiast, offers a closer look at the intricate details of a gemstone. For diamonds, this tool can reveal clues about their authenticity.

Steps to Use a Magnifying Glass:

  1. Clean the Diamond: Begin by ensuring your diamond is free from any dirt or smudges to get a clear view.
  2. Prepare Your Magnifying Glass: A 10x magnification is usually sufficient to view a diamond’s details.
  3. Inspect the Diamond: Carefully observe the diamond through the magnifying glass. Focus on the interior and surface of the stone.

What to Look For:

  • Inclusions: Genuine diamonds often have tiny imperfections or inclusions within them. If your diamond appears perfect inside without any blemishes or inclusions, it might be a cause for suspicion. However, high-quality diamonds can also have minimal inclusions.
  • Facet Edges: Real diamonds have sharp and crisp facet edges, while many imitations, like cubic zirconia, have rounded and smoother edges.
  • Engravings: Sometimes, genuine diamonds might have tiny inscriptions on the girdle from the gem lab or the jeweler.

Robert, an antique collector, once came across a vintage ring at an estate sale. The seller claimed it housed a genuine diamond.

Armed with a magnifying glass, Robert inspected the stone and noticed multiple inclusions and sharp facet edges, confirming the diamond’s authenticity.

He later got it appraised and found out it was a diamond from the early 1900s, making his purchase a valuable find.

A magnifying glass can reveal a diamond’s hidden world, offering insights into its authenticity. However, always consult with a gemologist for a conclusive evaluation.

Using a Black Light to See If Your Diamond Is Real

The black light test, often overlooked, can provide fascinating insights into the authenticity of a diamond. Under ultraviolet (UV) light, diamonds might exhibit a phenomenon called fluorescence.

While not all genuine diamonds fluoresce, the presence or pattern of fluorescence can sometimes offer clues about the stone’s genuineness.

Steps to Conduct the Black Light Test:

  1. Prepare a UV Light: Obtain a UV or black light, commonly available at hardware stores or online.
  2. Darken the Room: The effects are best observed in a dark setting.
  3. Shine the Light on the Diamond: Hold the UV light close to the diamond and observe any colors or patterns that emerge.

What to Look For:

  • Blue Fluorescence: A common fluorescence color in genuine diamonds is blue. If your diamond exhibits a medium to strong blue fluorescence, it’s a good sign. However, some genuine diamonds might not fluoresce at all.
  • Other Colors: While blue is the most common, diamonds can sometimes fluoresce in other colors like yellow or green. These are less common in genuine diamonds and might warrant further investigation.

It’s essential to remember that fluorescence alone isn’t a definitive indicator of authenticity.

Some synthetic diamonds or other gemstones might also fluoresce under UV light. Therefore, this test should be used as a supplementary method.

The Black Light Test can unveil the hidden fluorescence in diamonds, offering another layer of insight into their authenticity. Always combine this with other methods for a comprehensive evaluation.

How to Tell if Your Diamonds Are Real Using a Loupe

A jeweler’s loupe is a specialized magnifying tool commonly used in the gemology world.

Offering higher magnification than a regular magnifying glass, a loupe can reveal intricate details and inclusions within a diamond, providing valuable clues about its authenticity.

Steps to Inspect a Diamond Using a Loupe:

  1. Prepare Your Loupe: Ideally, use a loupe with 10x to 20x magnification.
  2. Position the Diamond: Place the diamond under a light source. Natural sunlight or a bright, color-neutral lamp works best.
  3. Inspect the Diamond: Look through the loupe and carefully examine the diamond, focusing on its interior and surface.

What to Look For:

  • Natural Inclusions: Real diamonds often have unique internal characteristics or inclusions. These can range from tiny crystals to feather-like patterns. While some high-quality diamonds may have very few inclusions, the presence of natural-looking inclusions can be a good sign.
  • Sharp Facet Edges: Genuine diamonds typically have sharp and well-defined facet junctions, while many imitations tend to have rounded edges.
  • Surface Blemishes: While not desirable from a quality perspective, surface blemishes, scratches, or nicks can sometimes indicate natural wear, suggesting the stone’s authenticity.

In 2015, a couple in San Francisco bought a vintage diamond necklace from an estate sale. While it lacked certification, they were intrigued by its design.

Using a jeweler’s loupe, they identified multiple natural inclusions and some wear patterns on the diamond’s surface, hinting at its age and authenticity.

A subsequent professional appraisal confirmed their suspicions, valuing the necklace much higher than their purchase price.

A jeweler’s loupe provides a closer look into a diamond’s world, revealing details that can confirm or question its authenticity.

Check Your Diamond’s Mount

Often, the setting or mount in which a diamond is placed can offer clues about its authenticity.

Jewelers typically use specific types of mounts for genuine diamonds to ensure their security and highlight their brilliance.

Here’s how the mount can help you in your quest to determine a diamond’s genuineness:

Steps to Inspect the Diamond’s Mount:

  1. Observe the Metal: Genuine diamonds are usually set in high-quality metals like platinum, white gold, yellow gold, or sometimes silver. Check for any hallmarks or stamps on the inside of the ring or jewelry piece.
  2. Examine the Setting: Real diamonds are often placed in sturdy settings like prong or bezel to protect them from potential damage. If the setting appears flimsy or poorly crafted, it may be cause for suspicion.

What to Look For:

  • Hallmarks: Genuine jewelry pieces usually have hallmarks indicating the metal’s purity, such as “14K” for 14 karat gold or “925” for sterling silver.
  • Craftsmanship: High-quality craftsmanship is typically a sign of genuine diamond jewelry. Look for even and secure settings, smooth finishes, and well-crafted details.

Vintage or heirloom pieces might not always adhere to modern setting standards. If you’re dealing with an antique piece, it’s even more crucial to consult an expert.

The mount and setting of a diamond can tell stories of its past and hint at its authenticity. However, especially with antique pieces, always combine this method with other tests and expert opinions.

Perform the Scratch Test to Determine If Your Diamond Is Real

The scratch test is one of the older methods used to check a diamond’s authenticity. Diamonds are renowned for their hardness, ranking a solid 10 on the Mohs scale.

This means that genuine diamonds can scratch almost any material, including glass and other gemstones.

Steps to Conduct the Scratch Test:

  1. Find a Mirror or Glass Surface: A clean, unobtrusive part of a mirror or a piece of glass is ideal for this test.
  2. Scratch the Surface: Gently, but with a bit of pressure, scratch the diamond against the glass or mirror.

What to Look For:

  • Scratch Mark: A real diamond should leave a scratch mark on the glass. If it doesn’t, the diamond might not be genuine.

This test comes with significant risks. If the stone is not a genuine diamond, the scratch test can damage or even shatter it.

Furthermore, even if it is a genuine diamond, the test might damage the setting or other parts of a jewelry piece.

While the scratch test can provide quick insights, it’s a risky method that can cause irreversible damage. It’s always safer to opt for non-destructive methods or seek professional advice.

Check Your Diamond’s Transparency

The transparency test, also known as the “read-through” test, is a simple method to gauge a diamond’s refractive properties.

Diamonds refract light so intensely that it’s usually impossible to see through them clearly, unlike many of their imitations.

Steps to Conduct the Transparency Test:

  1. Get a Newspaper or Printed Text: A page with clear, bold letters works best for this test.
  2. Place the Diamond on the Text: Lay the diamond flat-side down on the newspaper or printed text.
  3. Attempt to Read Through the Diamond: From a top view, try to read the text through the diamond.

What to Look For:

  • Blurred or Distorted Text: A genuine diamond will scatter light, making it nearly impossible to read text through it clearly. If you can read the text as if you were looking through a clear piece of glass, it’s likely not a real diamond.

Some diamonds, especially those with shallow cuts or certain inclusions, might allow more light to pass through, potentially skewing the test results. As always, it’s essential to combine this test with others for a more accurate assessment.

The Transparency Test offers a quick way to gauge a diamond’s refractive properties, but always ensure you’re considering the diamond’s cut and potential inclusions during the test.

Using Fire to Test Your Diamond

The fire test is a dramatic method based on the theory that diamonds, being composed of carbon, will resist fire, while most fakes will not. However, this test carries a risk and is not commonly recommended due to potential damage.

Steps to Conduct the Fire Test:

  1. Safety First: Ensure you’re in a safe environment away from flammable items. Use protective gloves and eyewear.
  2. Place the Diamond: Hold the diamond with a pair of tweezers.
  3. Expose to Fire: Using a lighter, expose the diamond to the flame for approximately 30 seconds.
  4. Drop into Cold Water: Immediately after heating, drop the diamond into a glass of cold water.

What to Look For:

  • Integrity of the Stone: A real diamond will remain unscathed due to its strong carbon bonds. Fake diamonds, like cubic zirconia, might shatter due to the rapid expansion and contraction from the temperature change.

This test is risky for several reasons:

  • It can damage genuine diamonds, especially those with inclusions that trap heat.
  • It can ruin the setting or other parts of jewelry.
  • Other stones or high-quality fakes might also withstand the fire test.

The Fire Test can be a dramatic demonstration, but its risks often outweigh the benefits. Always opt for safer, non-destructive methods when in doubt.

Using a Diamond Scale

Weight can be a revealing factor when determining a diamond’s authenticity, especially when compared to its size.

Diamonds have a specific density, and while it’s close to that of some imitations, subtle differences can sometimes be detected using a precise scale.

Steps to Use a Diamond Scale:

  1. Get a Precision Scale: These scales offer accuracy to the milligram and are commonly available at jewelry supply stores or online.
  2. Calibrate the Scale: Ensure it’s calibrated correctly for accurate readings.
  3. Weigh the Diamond: Place the diamond on the scale and record its weight.

What to Compare:

  • Weight vs. Size: Compare the weight of the diamond to its size (diameter if it’s round). Real diamonds and cubic zirconia, for instance, are close in density, but cubic zirconia is slightly denser. This means a CZ stone will weigh more than a diamond of the same size.

Table: Approximate Weights for a 6.5mm Round Stone

MaterialApproximate Weight (carats)
Cubic Zirconia1.65

While the weight can offer clues, many factors can affect a diamond’s weight, including its cut, shape, and even the presence of inclusions. Always use weight as a supplementary method and not as the sole determinant.

A jeweler in Antwerp once received a stone that looked identical to a diamond in size and shape. However, upon weighing, the stone was noticeably heavier than expected for its size. Further tests revealed it to be moissanite, a diamond simulant.

A diamond scale can provide insights into a diamond’s genuineness, but always cross-check with other tests for a more holistic assessment.

Observing Your Diamond’s Sparkle to Determine If It’s Real

The sparkle of a diamond, often referred to as its “fire” and “brilliance,” is one of its most captivating features.

Real diamonds reflect light in a unique way that sets them apart from most other gemstones.

Steps to Observe a Diamond’s Sparkle:

  1. Clean the Diamond: Ensure the diamond is free from smudges or dirt to get an accurate observation.
  2. Find a Light Source: Natural sunlight is ideal, but a well-lit room can also work.
  3. Examine the Reflections: Move the diamond back and forth, observing the colors and patterns of light it reflects.

What to Look For:

  • White Light Reflections (Brilliance): Genuine diamonds reflect a significant amount of white light, giving them a bright sparkle.
  • Colorful Light Reflections (Fire): Real diamonds also refract light into a spectrum of colors, producing flashes of red, blue, and green.
  • Pattern and Consistency: Genuine diamonds produce a consistent and balanced play of brilliance and fire throughout the stone. Many imitations might have uneven or overly colorful reflections.

While observing sparkle can offer insights, it’s also influenced by the diamond’s cut and quality. A poorly cut genuine diamond might not sparkle as brilliantly as a well-cut one.

The mesmerizing sparkle of a diamond can hint at its authenticity, but it’s crucial to recognize the balance of brilliance and fire that genuine diamonds exhibit.

Tips for How to Know If Your Diamond Is Real

After exploring various methods to determine a diamond’s authenticity, it’s essential to remember a few overarching tips and considerations:

  • Professional Opinion is Gold Standard: No matter how many home tests you conduct, always seek a certified gemologist’s opinion for a conclusive answer.
  • Certifications Matter: When purchasing a diamond, inquire about its certification. Reputable labs like the Gemological Institute of America (GIA) or the American Gem Society (AGS) provide certifications that detail a diamond’s properties and confirm its authenticity.
  • Beware of Terminology: Be cautious of terms like “lab-created,” “synthetic,” or “cultured” diamonds. While they are real diamonds in terms of composition, they are grown in labs and usually cost less than natural diamonds.
  • Trust but Verify: Even if you’re buying from a reputable dealer, it doesn’t hurt to verify the diamond’s authenticity. It ensures peace of mind and confirms the value of your purchase.

Quick Tips for Diamond Authenticity

TipWhy It’s Important
Always get a professional opinionProvides a conclusive answer based on expertise
Look for certificationsOffers assurance of the diamond’s properties and genuineness
Understand the terminologyHelps in making an informed purchase
Even with trusted dealers, verify authenticityEnsures peace of mind and value for money

While home tests and observations can offer valuable insights, always rely on expert opinions and certifications for a diamond’s definitive assessment.

Read Also: Why Round Diamonds are Pricier than Princess Diamonds


Diamonds, with their unparalleled sparkle and allure, have captivated humanity for centuries. They symbolize love, commitment, and life’s significant milestones.

Given their immense value, both monetary and sentimental, ensuring their authenticity is of paramount importance.

Throughout this guide, we’ve explored various methods, from the simple fog test to the more intricate examination under a loupe, to determine a diamond’s genuineness.

Each method offers a unique perspective, but the overarching lesson remains: always seek professional validation.

The world of diamonds is vast and intricate. Each stone, with its inclusions and unique light play, tells a story.

As you embark on your journey, whether it’s purchasing a new piece or inheriting a family heirloom, let knowledge be your guiding light. Arm yourself with information, ask the right questions, and always prioritize verification.

In the words of the renowned gemologist, Dr. Fiona Atwood:

“A diamond’s true beauty lies not just in its sparkle but in the confidence of its authenticity.”

Knowledge is power. Equip yourself with the tools and insights to confidently assess a diamond’s genuineness, ensuring that its brilliance is matched only by its authenticity.