How to Tell if Diamonds Are Real: Guide to Authenticity

A diamond's sparkle is appealing because of its beauty and timelessness, and its value is priceless. But with so many convincing alternatives on the market, how to tell if diamonds are real? is more crucial than ever. If a treasured family heirloom or a newly-purchased item caught your fancy or you have a favorite gemstone you'd like to verify, it's good to know how to tell the real deal from an impostor. At Shiree Odiz we have been manufacturing and selecting fine jewellery for over 20 years and we feel that anyone can learn to confidently spot a real diamond.

This massive guide will guide you through both easy, at-home tests and professional evaluations to help you be sure whether or not what you have on your hands is actually a diamond.

How to Tell if Diamonds Are Real: At-Home Tests

No at-home test is perfect, but these might give you a good idea if you have a real vs a fake diamond. They take advantage of the distinct physical and optical characteristics of natural diamonds.

1. The Fog Test:
   

• How to do it: Hold the diamond up between two fingers and breathe on it the way you would to fog up a mirror.
  

• What to look for: A real diamond will disperse heat almost immediately because it’s a very good thermal conductor. If the fog clears the fog abruptly in 1-2 seconds), you’re probably watching the action live. If the fog takes more than a few seconds to dissipate, it’s likely a simulant, like glass or cubic zirconia, that doesn’t conduct heat as well.

• Why it works: Diamonds are among the most efficient heat conductors on the planet. The warmth and wetness of your breath evaporates from the surface of the diamond.
  
  

2. The Water Test (Density Test):
   

• How to do it: Fill a regular drinking glass three-quarters full with water. Carefully put the diamond on the glass.
  

• What to look for: A real diamond has a very high density (specific gravity of approximately 3.52 g/cm³). It will sink rapidly to the bottom of the glass. Most fake diamonds, being less dense, will float or hover just below the surface.
  

• Why it works: The trick is based on the physics of density. It is much denser than most common diamond simulants. Note: This is the perfect test for loose diamonds. And if you have a piece of junky jewelry, the metal setting won’t allow it to float, and even if it does, it will sink whether there is a diamond involved in the test or not, which could lead to inaccurate results.
  
  

3. The Dot Test (Read-Through Test):
   

• How to do it: Lay down a piece of white paper on a flat surface and draw a small dot on it with pen. Place the loose diamond down flat right over that dot with the flat table facet against the paper. Just look down through the point of the diamond.
  

• What to look for: If you’re looking through a real diamond, you shouldn’t be able to see the dot, or at the very least, it will be extremely distorted a blurred circle. The specific way in which a diamond refracts and bends light distracts you from being able to clearly see through to the other side. If you can see the spot (or a sharp reflection in the spot) the hologram is probably fake.
  

• Why it works: Diamonds have a very high refractive index (2.42), so light bends sharply within the stone, spreading in all directions instead of propagating in a straight line all the way though.
  
  

4. The Sparkle Test (Light Performance):
   

• How to do it: Hold the gem under a standard lamp (not direct sunlight or harsh spotlights — too bright for the eye). Watch as light reflects off the stone.
  

• What to Look For (and What to Avoid): A natural diamond will have a variety of types of sparkle:
  

• Brilliance: Bright flashes of white light from within the diamond.
  

• Fire: Rainbow colored flashes (like a prism effect) of light visible on the surface of the diamond, particularly when the diamond is tilted.
  

• Scintillation: The flashes of light and dark areas that are visible when the diamond is moved. An actual diamond's interior fire will be mostly white and gray, and exterior reflections will display rainbow colors. In contrast, fake diamonds tend to take on an "over-sparkle" look, in which rainbow light filtering through the stone shifts and moves with wear, called the "disco ball" effect.
  

• Why it works: A diamond’s excellent cut is intended to optimize the amount of light reflected and scintillation — the flashes of color — the diamond produces. Simulants often have other refractive indices and dispersion qualities, causing them to be duller or more brilliant.
  
  

5. The Metal Setting Markings:
   

• How to do it: If the diamond is mounted in a ring or in real diamond earrings, examine the metal to see if there are any marks or stamps.
  

• What to look for: Genuine diamonds are nearly always mounted in precious metals such as gold or platinum. Look for markings such as:
  

• Gold: 10K, 14K, 18K, 24K (or numbers like 417, 585, 750, 999 indicating gold purity).
  

• Platinum: PT, Plat, 950 Plat.
  

• Silver: S925 or .925 (though diamonds are less commonly set in silver due to its softness).
  

• Why it works: A real diamond wouldn’t be set in a cheap metal that is un-stamped. While this is not proof that the diamond is real, it is a good indication that the setting is valuable as well, and is likely a real diamond.

Real vs Fake Diamond: Understanding Common Simulants

To really address how can you tell if it’s real diamonds?, you will need to understand what you may be matching the diamonds to? There are lots of things that look like diamonds but have very different backbones.

• Moissanite: Features (hardness 9.25, RI and dispersion that is higher than diamond). It also shows double refraction, a view of a point through a diamond reveals two wavelengths of light slightly separated.
  

• White Sapphire/Topaz: These are genuine gemstones much softer than diamond(Sapphire 9, Topaz 8), in terms of comparison with "fire". They feel not as hard as a real diamond.
  

• Glass: It has a hardness of 5.5 on Mohs scale so it is very easy to scratch and does not shine or does not has fire like diamond. In many cases, it will have bubbles or swirls throughout.
  
  

How to Test a Diamond Professionally

For complete authentication, especially with pricier pieces, or if you’re unsure after trying home tests, professional examination is essential.

1. Diamond Tester (Thermal/Electrical Conductivity):

• How it works: Jewelers wield hand-held testers that measure a diamond’s thermal or electrical conductivity. A true diamond will conduct heat very well and will register on the tester. Virtually all simulates are non- conductive for heat and electricity.
  
  
• Limitations: On an extreme occassion, diamond (with high level of impurities in it) could have the color-purple and hence will show a positive reaction to basic nextel (since it conducts heat as well) so you need a better electrical condutor to dif it from Diamond.
  
  

2. Loupe Examination:

• How to do it: A jeweler’s loupe (a 10x magnification small magnifying glass) is your best friend.
  
  
• What to look for:
  
  
  • Inclusions: Real diamonds are made from a natural process, under intense pressure and heat, and therefore almost always contain internal characteristics that gemologists refer to as “inclusions,” (unless it is Flawless, which virtually you’ll never see). These could be little crystals, feathers, or clouds. If a stone is perfect under 10x magnification, it should also serve as a warning that it could be a simulant.
    
    
  • Facet Junctions: Genuine diamonds have sharp and exact facet junctions. Junctions of simulants possibly could be more rounded or worn.
    
    
  • Girdle: A genuine diamond's girdle (the rim between the top and bottom) can be faceted, bruted (rough), or polished. Three different types of girdle representations are found in simulates.
    
    
  • Double Refraction (for Moissanite): For moissanite, when you look through the pavilion with a loupe you will see the facet edges “double”, as it does not have single-refractive diamonds.
    
    

3. UV Light Test:

• How to do it: Expose the diamond to a UV (black) light in a dark room.
  

• What to look for: Fluorescence occurs in about 25-35% of natural diamonds, but it’s usually a blue glow. If your diamond shines a blue light, it is a good sign the diamond is real. On the other hand, some natural diamonds do not fluoresce, and others may fluoresce in colors other than blue (e.g., yellow, green). “Fluorescence is one of the most misunderstood traits in diamonds. In most cases, it does absolutely no harm—and can even enhance the look of warmer stones. For savvy buyers, that’s an opportunity.” – Daniel Setton, Co-Founder. So while the blue glow is a good sign, the lack of a glow, or a different color, doesn’t necessarily make the stone fake.
  
  

4. Weighing and Measuring:

• How to do it: A gemologist can then weigh the diamond precisely and take its dimensions.
  

• What to look for: The specific gravity is found by dividing the weight by the volume (which is obtained using volume measurements). That is because each has its own unique density thereby allowing it to be a very good density filtration for separating diamonds from simulants.
  
  

5. Professional Gemological Certification:

• The final Authentication: The most reliable way to authenticate a diamond is through a diamond grading report, from a reputable and independent gemological laboratory. For example, the GIA, IGI, and AGS are the most commonly known and accepted institutions that issue impartial and precise grading reports with detail descriptions of the diamonds’ 4 Cs, dimensions and fluorescence that are also accompanied by a plot of the diamonds’ inclusions. This is what people within the trade would expect as it acknowledges what the stone is and it’s “worth”.

How Do I Know if the Diamonds Are Real in Settings? (Focus on Real Diamond Earrings)

If you want to test diamonds already set in jewelry, a few tests will differentiate a real diamond from a simulant, but not all at-home tests are reliable (once a diamond is inserted into a setting, you won’t be able to perform a water test for density, as one example, because the density of the metal will skew the results).

• Visual Inspection of the Setting: Genuine diamonds are set in good quality metals (gold, platinum or occasionally sterling silver for smaller stones). Look at the work in the setting. Genuine diamonds are almost always set with attention to detail and fine metal work. Prong prong should be even, secure, and polished. Substandard workmanship, glue that you can see or flimsy settings can be warning signs.
  

• Sparkle Test in Setting: The sparkle test is just as effective with set diamonds. Observe the brilliance and fire. Real diamond earrings, even tiny ones, should sparkle white with shines of rainbow color.
  

• Fog Test: This can still be performed on set diamonds.
  

• Professional Assessment: If you think you have diamond earrings, especially good ones or if you have any doubt at all, a professional jeweler or gemologist can do what’s called a thermal test to determine temperature fluctuations in the stones, take a look through a loupe, and give you a professional appraisal (without taking the stones out of their setting). They can also test for secure settings, very important when it comes to earrings.

How Can You Tell if It's Real Diamonds: The Shiree Odiz Advantage

The road to an assured response to “how can you tell if its real diamonds” is considerably stronger when you have worked with a reliable jeweler. Here at Shiree Odiz we believe in one above all - honesty, transparency, ethics.

We pride ourselves on:

• Expert Advice: With 20 years’ direct industry experience, our founders Shiree and Daniel. They are true diamond experts, understanding every facet from design to sourcing.
  

• Transparent Sourcing: We divulge all of the details of our diamonds, both natural and lab-grown, including origin and attributes.
  

• Quality Craftsmanship: We use a model of “slow jewelry" that crafts each piece to order with care and precision that matches the security and value of each stone. “Our designs are made to protect a diamond’s weak spots—culets, corners, and edges are never left exposed. Prongs are shaped and positioned to buffer accidents, and we only work with the finest setters for this exact reason. We don’t want to break our diamonds either.” – Shiree Odiz, Head Designer. This commitment to artisan workmanship also ensures the integrity and value of your diamond jewelry.
  

• Education: We are true believers in the old adage that knowledge is power and that is precisely what this guide is empowering.

Conclusion

Knowing how to tell if diamonds are real, though, is very helpful for jewelry owners or anyone looking to purchase a diamond. While at-home diamond tests could offer you some early clues, the most important is about learning the properties of diamonds and their typical simulants. For real clarity, and a piece of mind, especially when purchasing big ticket items like an engagement ring or for true real diamond earrings, when in doubt, have this confirmed by a trained gemologist or respected jeweler.

At the end of the day, nothing will ever come close to the incomparable sparkle, fire, and a one-of-a-kind nature of a real diamond! With this info (and a little guidance from an entertaining psychic), you’ll never again question all the sparkle and intrinsic value of your precious stones.