How to Tell if a Diamond is Real or Fake?

How to Tell if a Diamond is Real or Fake?

Diamonds, those mesmerizing gemstones that have captured human fascination for centuries, are revered for their brilliance and allure. However, in a world filled with imitations and look-alikes, it's essential to have the knowledge and tools before you buy diamond necklaces or other fine jewelry in Los Angeles to differentiate a natural diamond from a counterfeit. But how can you tell if a diamond is real or fake? Fortunately, several DIY tests can help you distinguish authenticity from imitation, allowing you to make informed decisions about your precious gemstones.

Water Test

The water test is a quick and easy at-home method to help determine whether a diamond is real or potentially fake. This test capitalizes on the fact that diamonds are highly effective heat conductors, and as a result, they disperse heat rapidly. To perform the water test, follow these simple steps:

Step 1: Fill a glass with cold water. The water should be at room temperature or slightly cooler.

Step 2: Hold the diamond you want to test between your fingers. The idea here is to warm the diamond with the heat from your fingers.

Step 3: Gently drop the loose diamond into the glass of water.

Step 4: Observe the diamond as it sinks to the bottom of the glass.

Now, here's what you should look for:

- If the diamond sinks quickly: This is a positive sign. A natural diamond is denser than water, so that it will sink rapidly.

- If the diamond floats or remains suspended: This could indicate that the diamond is fake. Most synthetic diamond imitations, such as cubic zirconia or moissanite, are less dense than water, causing them to remain afloat or suspended in the water.

Fog Test

The fog test is another simple and quick at-home method of how to see if a diamond is real or fake, and it can help you in your quest to distinguish natural diamonds from fake ones. This test relies on the fact that diamonds disperse heat quickly, just like in the water test. Here's how you can perform the fog test:

Step 1: Clean the diamond's surface to ensure no residue or oils might interfere with the test.

Step 2: Hold the diamond between your fingers or use a pair of tweezers. You want the diamond to be at room temperature for accurate results.

Step 3: Breathe on the diamond, creating a layer of condensation or fog on its surface, similar to how you might fog up a mirror with your breath.

Step 4: Quickly observe how the fog behaves on the diamond.

Now, here's what to look for:

- If a diamond is natural, it will disperse heat so efficiently that it will cause the fog to clear almost immediately, and this happens because the diamond quickly raises its temperature, making it appear as if the fog has evaporated on contact.

- If the light fog remains for a few seconds, it may indicate that it is a synthetic diamond. Diamond imitations disperse heat less efficiently, so the fog will linger longer before dissipating.

Heat Test

The heat test is a bit more advanced and requires caution, so using this method carefully is advisable. This test capitalizes on diamonds' heat conductivity and is unsuitable for all jewelry settings. Here's how to perform the heat test:

Step 1: Ensure that the setting or jewelry piece allows direct contact with a heated object, such as a heated needle or probe. Avoid using this test on fragile or heat-sensitive environments.

Step 2: Heat a needle tip or probe until it becomes red-hot. You can use a lighter or a flame to achieve this.

Step 3: Gently touch the red-hot tip of the needle or probe to a less conspicuous part of the diamond, such as the stone's girdle or edge. Do not touch the diamond's table (top surface), as it may damage the setting or affect its appearance.

Step 4: Observe the diamond's reaction to the heat.

Now, here's what to look for:

- If the diamond remains unharmed: Real diamonds are exceptional heat conductors that disperse the heat quickly without adversely affecting the stone.

- If the diamond gets damaged: Certain diamond imitations, like cubic zirconia or synthetic moissanite, may not withstand the heat and could get damaged or even crack upon contact with the red-hot tip.

Dot Test

The dot test is a straightforward examination that can help you in your quest to distinguish between natural diamonds and fakes. This test relies on the fact that most diamonds have unique optical properties. Here's how to perform the dot test:

Step 1: Place the diamond on a white sheet of paper or a white surface, ensuring adequate lighting.

Step 2: Select a point on the diamond to focus on, which can be any point on the stone's surface, but choosing a spot with visible characteristics, like inclusion or blemish, is typically best.

Step 3: While looking directly down onto the chosen point, attempt to read a straight line of text or numbers through the diamond. You can use a book, magazine, or any printed material.

Step 4: Pay close attention to what you see. Observe how the text appears when viewed through the diamond.

Now, here's what to look for:

- If you can easily read the text or numbers, this may indicate that the diamond is a fake. Natural diamonds have unique optical properties that typically bend and refract light in such a way that it can distort the text or make it difficult to read.

- If the text appears distorted or is challenging to read, this suggests that the diamond is real. Diamonds have a high refractive index, which causes light to bend as it passes through the stone. This bending of light can make the text appear distorted or blurred when viewed through a natural diamond.

Magnifying Glass or Loupe Test

The magnifying glass or loupe test is a valuable tool for closely examining the characteristics of a diamond, as well as any potential imperfections that may reveal its authenticity. Here's how to perform the magnifying glass or loupe test:

Step 1: Obtain a jeweler's loupe or a high-powered magnifying glass. These tools typically have magnification levels of 10x or higher, ideal for inspecting diamonds.

Step 2: Place the diamond on a clean, well-lit surface. Ensure that no obstructions or reflections might interfere with your examination.

Step 3: Hold the magnifying glass or loupe approximately 1 inch (2.5 cm) away from your eye. If you wear glasses, keep them on for better focus.

Step 4: Gently pick up the diamond using tweezers or a soft cloth. Position the diamond to view it through the loupe or magnifying glass.

Step 5: Examine the loose stone by focusing on the loose diamond’s overall appearance and any unique identifying characteristics, such as inclusions, blemishes, or specific growth patterns.

Step 6: Carefully inspect the diamond's facets or flat surfaces. Look for irregularities, such as scratches, chips, or inconsistencies in facet shape or alignment.

Step 7: Pay attention to how light interacts with the diamond. You should see a play of light and colors as the diamond refracts and reflects light, known as the diamond's "fire," a distinctive feature of genuine diamonds.

Step 8: Continue your examination by observing the diamond's girdle, the edge that encircles the stone. Check for any engravings or inscriptions that may provide information about the diamond's authenticity or origin.

Investigate the Mount and Settings

When determining the authenticity of a diamond ring, remember to closely examine the mount and settings that hold the stone in place. This test is an excellent way of - “how to tell if a diamond ring is real or fake.” The setting's design shape, material, and craftsmanship can provide valuable clues about whether the diamond is real or fake.

Metal Quality: Start by assessing the metal used in the setting, as authentic diamonds are likely set in high-quality precious metals like platinum, gold (yellow and white gold), or sterling silver. Examine the metal for hallmarks or stamps indicating its purity or quality. A genuine diamond is more likely to be set in fine materials.

Craftsmanship: Inspect the setting's craftsmanship and attention to detail. Genuine diamonds, placed in well-crafted settings, secure the stone firmly and showcase it elegantly. Look for signs of quality artistry, such as smooth edges, secure prongs, and precise alignment.

Prongs: Pay special attention to the mounted diamond prongs. In most cases, authentic diamonds feature secured prongs that cover a significant portion of the stone's surface. These prongs are usually well-made and precisely positioned to hold the diamond securely. If the prongs appear flimsy, uneven, or poorly placed, it may raise suspicions about the diamond's brilliance and authenticity.

Gaps and Movement: Inspect the setting for noticeable gaps or spaces between the diamond and the metal. Natural diamonds are typically set snugly, with minimal gaps. If you can quickly move or rotate the diamond within its setting, it may suggest it's not genuine.

Gemstone Support: Some settings feature small gemstones surrounding the central stone, such as accent diamonds or gemstone accents. Examine these supporting gemstones for authenticity as well. A mix of high density of real and fake jewels within a single piece of jewelry can indicate a counterfeit.

The UV Light Test

How do you tell if a diamond is real or fake? The UV (ultraviolet) light test is a valuable tool for distinguishing between genuine and counterfeit diamonds by assessing their fluorescence. Here's how the test works:

Step 1: Obtain a handheld UV light source, a black light. These devices emit ultraviolet light, which is not visible to the naked eye.

Step 2: Ensure that you are in a dark or dimly lit room to enhance the visibility of fluorescence.

Step 3: Hold the diamond under the UV light source and observe its reaction. Genuine diamonds often exhibit a blue fluorescence when exposed to UV light. This blue fluorescence is usually faint, but it's a common characteristic of many natural diamonds.

Step 4: Pay close attention to the intensity and color of the fluorescence. While blue-colored glow is typical for natural diamonds, some flawless diamonds may fluoresce in different colors or may not fluoresce at all. The absence of fluorescence does not necessarily indicate a fake diamond, as not all genuine diamonds fluoresce.

Step 5: If the diamond exhibits a strong and unnatural fluorescence, such as a bright yellow or green glow, it may suggest that it is fake. Some diamond substitutes, particularly cubic zirconia, may emit strong and unusual fluorescence under UV light.

Sparkle Test

The sparkle test is a simple yet effective way to evaluate the optical properties of a diamond and assess its authenticity. Genuine diamonds are renowned for their brilliant sparkle and play of light. Here's how to perform the sparkle test:

Step 1: Find a well-lit area with natural or artificial light to examine the diamond.

Step 2: Hold the diamond by its girdle, which is the edge that encircles the stone, using tweezers or a clean, soft cloth.

Step 3: Position the diamond so that you can view it from various angles, particularly under direct light sources.

Step 4: Observe how the diamond interacts with light. Pay attention to the following characteristics:

- Brilliance: Real diamonds typically display exceptional brilliance, characterized by a bright white light reflection.

- Fire: Fire refers to the dispersion of light into the diamond scale of various spectrum colors. Look for flashes of color, or "fire," within the diamond when it moves or when you change your viewing angle. Authentic diamonds often exhibit intense fire.

Step 5: Compare the observed characteristics with what you expect from a natural diamond—genuine diamonds known for their exceptional brilliance, intense fire, and lively scintillation. If the diamond exhibits these qualities, it may indicate its authenticity.

The Read Through Test

The read-through test is a straightforward technique that can help you differentiate between natural diamonds and their imitations, which may include cubic zirconia or glass. This test exploits the fact that diamonds have a high refractive index, which affects how text appears when viewed through the stone.

Step 1: Find a small piece of paper with text, such as a page from a book, a newspaper, or a printed document.

Step 2: Place the diamond on a flat surface with the table (the flat top surface of the diamond) facing down.

Step 3: Position the paper with text beneath the diamond so you can see the text through the stone.

Step 4: Observe the text as you look through the diamond.

Step 5: If you're viewing a natural diamond, the text should appear significantly distorted or unreadable. The high refractive index of the diamond causes a phenomenon known as "diamond's birefringence," which bends light differently than air or other materials. As a result, the text will break up and become difficult to read.

Step 6: In contrast, if you can easily read the text through the stone without significant distortion, it may indicate that the diamond is not genuine. Specific imitations, like cubic zirconia or glass, have a lower refractive index than natural diamonds and do not produce the same level of distortion.

By Using a Diamond Tester

Consider using a diamond tester for the most reliable and conclusive results in determining whether a diamond is real or fake. 

Step 1: Obtain a handheld or diamond tester pen readily available at jewelry stores or online retailers.

Step 2: Ensure that the diamond you want to test is clean and free of any oils, residues, or other substances that may interfere with the test.

Step 3: Follow the manufacturer's instructions for operating the diamond tester. Generally, this involves turning on the device and allowing it to calibrate.

Step 4: Place the diamond tester's probe or tip against the surface of the diamond.

Step 5: Wait for the device to provide a reading. Diamond testers typically display a result indicating whether the stone is a natural diamond.

Step 6: Interpret the results. If a scratch test by the tester indicates that the stone is a diamond, it's likely to be genuine. However, if it suggests that the stone is not a diamond, further examination and testing may be needed to confirm the result.


In the world of diamonds, determining whether a diamond is real or fake can be a challenging but essential task. While no single test is foolproof, combining methods can significantly increase your confidence in identifying authentic diamonds. Consider the water test, fog test, heat test, dot test, magnifying glass or loupe test, investigation of the mount and settings, UV light test, sparkle test, read-through test, and using a diamond tester.

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