How to tell if a diamond is real

Diamonds have captivated and fascinated people for centuries with their beauty, rarity, and value. However, with the increasing sophistication of synthetic diamonds and diamond imitations, it has become essential to know how to differentiate between a real diamond and a fake one. In this article, we will explore the characteristics of real diamonds and various testing methods that can help you determine the authenticity of a diamond.

diamond is real

What are Diamonds?

Before we delve into identifying real diamonds, let’s understand what diamonds are. Diamonds are natural gemstones formed deep within the Earth’s crust over millions of years under extreme pressure and heat. They are composed of carbon atoms arranged in a crystal lattice structure, which gives them their exceptional hardness and brilliance.

Characteristics of Real Diamonds

Real diamonds possess several unique characteristics that set them apart from imitations. By understanding these characteristics, you can become better equipped to distinguish between real and fake diamonds.

Brilliance and Sparkle

One of the most prominent features of diamonds is their brilliance and sparkle. Real diamonds have excellent light-reflecting properties that result in a dazzling display of white light, known as the “diamond fire.” When light enters a diamond, it undergoes internal reflection and refraction, dispersing the light into spectral colors.

Refractivity and Light Dispersion

Diamonds have a high refractive index, which means that light bends as it passes through the stone. This phenomenon, known as light dispersion or the “diamond rainbow effect,” causes the light to split into its component colors, creating a stunning play of colors. The higher the dispersion, the more pronounced the rainbow effect.


Diamonds are the hardest natural substance on Earth, ranking 10 on the Mohs scale of mineral hardness. This exceptional hardness makes diamonds resistant to scratches and gives them the ability to maintain their polish and shine over time. If a material other than another diamond can scratch the stone, it is likely not a real diamond.


Another characteristic of real diamonds is their density. Diamonds have a relatively high density, which means they feel heavier compared to most other gemstones of a similar size. A noticeable difference in weight can indicate the authenticity of a diamond.

Heat Conductivity

Diamonds are exceptional conductors of heat. One way to test a diamond’s authenticity is by conducting a heat test. Hold the stone close to your mouth and breathe on it. If the fog clears up immediately, it may indicate a real diamond, as diamonds disperse heat rapidly.

Testing Methods for Real Diamonds

While understanding the characteristics of real diamonds is helpful, several testing methods can provide more conclusive results. Here are some common methods used to test the authenticity of diamonds:

Visual Inspection

A visual inspection is the first step in identifying a real diamond. Examine the stone under good lighting and observe its brilliance, sparkle, and clarity. Real diamonds often exhibit exceptional light performance and lack any noticeable flaws or blemishes.

Fog Test

The fog test is a simple and quick way to determine if a diamond is real. Breathe on the stone as you would for a heat test. If the fog dissipates immediately, it is likely a real diamond. However, if the fog lingers for a few seconds or appears as a film, it might be a fake diamond.

Water Test

The water test can help identify whether a diamond is real or not. Place the diamond into a glass of water. Due to their high density, real diamonds should sink to the bottom of the glass. If the stone floats or remains suspended in the water, it is likely an imitation.

Heat Test

A heat test involves exposing the diamond to heat briefly. Use a pair of tweezers and hold the stone close to a flame for around 30 seconds. Then, drop the diamond into a glass of cold water. If the stone shatters, it is likely not a real diamond, as diamonds are highly heat-resistant.

Diamond Tester

A diamond tester is a portable electronic device that helps identify real diamonds. It measures the electrical conductivity of the stone, as diamonds are excellent conductors. However, this method may not be foolproof, especially when dealing with synthetic diamonds or certain diamond imitations.

Professional Appraisal

For a more accurate assessment, consider seeking a professional appraisal from a qualified gemologist or jeweler. They have the expertise and equipment to examine the diamond thoroughly and provide a definitive answer regarding its authenticity.

Common Misconceptions about Diamond Testing

It’s important to address some common misconceptions about diamond testing to avoid confusion or misinterpretation of results. One common misconception is that the “scratch test” is a reliable method to test a diamond. However, this method can damage the stone and is not recommended. Additionally, relying solely on a single testing method may not provide conclusive results, as some synthetic diamonds or imitations can exhibit similar properties to real diamonds.


Distinguishing a real diamond from a fake one can be a challenging task, given the availability of sophisticated imitations. However, by understanding the characteristics of real diamonds and employing various testing methods such as visual inspection, fog test, water test, heat test, diamond testers, and professional appraisals, you can increase your chances of accurately identifying a real diamond. Remember to exercise caution when purchasing diamonds and consult with reputable jewelers or gemologists to ensure the authenticity of your precious gemstone.


1. How can I tell if a diamond is real just by looking at it?

Visual inspection is the first step in identifying a real diamond. Look for exceptional brilliance, sparkle, and clarity, and ensure there are no noticeable flaws or blemishes.

2. Can a fake diamond sparkle like a real one?

While some diamond imitations may have some sparkle, they typically lack the unique brilliance and fire of real diamonds.

3. Are lab-created diamonds real diamonds?

Lab-created diamonds are real diamonds. They have the same chemical composition, physical properties, and optical characteristics as natural diamonds.

4. Are there any foolproof tests to determine diamond authenticity?

No single test is foolproof. Employing a combination of testing methods, including visual inspection, fog test, water test, heat test, diamond testers, and professional appraisals, can provide more accurate results.

5. Should I get my diamond tested by a professional before purchasing it?

If you are uncertain about the authenticity of a diamond, it is advisable to seek a professional appraisal from a qualified gemologist or jeweler before making a purchase.

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