How to Identify if a Diamond is Real or Fake

Diamonds are likely the world's most valuable and sought-after gemstones. However, with the introduction of synthetic gemstones and diamond look-alikes like cubic zirconia and moissanite, it is at times difficult to distinguish a real diamond from an imitation.

Suppose you are purchasing a diamond for an engagement ring or need to know whether a piece you already own is real. In that case, there are several options to verify a diamond's authenticity.

In this blog, we will deep dive into the techniques by which you can find out if the diamond in your hand is real or fake.

Techniques for Differentiating Between a Real and Fake Diamond

There are many home tests and professional methods used to ascertain if a diamond is real.

1. Water Test

This is one of the simplest ways to check for authenticity.

How to do it:

• Fill a glass of water.

• Drop the diamond into the glass.

• A real diamond will sink due to its high density, while a fake diamond (such as glass or cubic zirconia) will float or sink slowly.

2. Fog Test

A quick test that checks how a diamond reacts to condensation.

How to do it:

• Hold the diamond near your lips and blow on it softly, as if you were trying to fog a mirror.

• A genuine diamond will dispel the mist immediately, as it possesses superior heat conduction.

• A diamond simulant will remain clouded for a few moments. You will see a distinguishable difference between the two.

3. Heat Test

Diamonds are highly resistant to heat, unlike fake gemstones.

How to do it:

Place a lighter to heat the diamond for about 30–40 seconds. Just drop it in cold water immediately.

A real diamond will retain its form, while an imitation one, say glass, will shatter or break.

4. UV Light Test

Some diamonds exhibit fluorescence under ultraviolet (UV) light.

How to do it:

Put the diamond under a black light (UV light). Most natural diamonds fluoresce blue under UV light, while imitation diamonds do not fluoresce.

However, not all natural diamonds are non-fluorescent, and therefore this test is not conclusive.

5. Direct Sunlight Test

A diamond’s brilliance is a key indicator of its authenticity.

How to do it:

Put the diamond in the sun. A genuine diamond will reflect rainbow light (fire) and white light (brilliance). Imitation diamonds are typically flat or have too much rainbow reflection.

6. Flashlight Test

A quick test to check how light interacts with the diamond.

How to do it:

Pass a light through the diamond. A real diamond will glint with clear, white light reflections. Imitation diamonds, e.g., glass, tend not to yield as much glint.

7. Black Light Test

An alternative way to check fluorescence.

How to do it:

In a darkened room otherwise, use a black light. Natural diamonds will fluoresce blue, while imitation diamonds will fluoresce green, yellow, or not at all.

8. Thermal Conductivity Test

Diamonds disperse heat quickly, unlike fake gemstones.

How to do it: 

Employ a diamond tester, a device designed to measure thermal conductivity. A real diamond loses heat quickly, but fakes like cubic zirconia retain heat.

9. Magnetism Test

Some synthetic diamonds contain metals that can react to magnets.

How to do it:

• Place a strong magnet close to the diamond.

• If the stone shifts or exhibits a reaction, it is probably a synthetic diamond imbued with metallic traces.

10. Scratch Test

Diamonds are the hardest known material, making them scratch-resistant.

How to do it:

• Utilize a shard of glass and attempt to engrave it with the diamond.

• A genuine diamond will easily scratch the glass.

• This test should however be avoided since the diamond and the glass can get damaged.

11. Dot Test

A simple test to check light refraction.

How to do it:

• Place a dot on a white piece of paper.

• Place the diamond gently over the dot and look through it.

• A genuine diamond bends the light so intensely that the dot will not be observable by the naked eye, whereas imitation diamonds will make it visible.

12. Refractive Index Test

Diamonds bend light differently than fakes.

How to do it:

• Put the diamond in front of your eye and look through it.

• A genuine diamond will diffuse light, and it will be hard to see through.

• Imitation diamonds, such as glass, allow you to see through the stone.

Buy GIA or IGI Certified Diamonds Only

The best way to ensure a diamond is real is to purchase a certified stone.

Why Certification Matters

Certified diamonds come with a grading report from recognized global institutions such as:

• GIA (Gemological Institute of America)

• IGI (International Gemological Institute)

These reports verify the diamond’s authenticity, quality, and characteristics, ensuring you are getting a real and ethically sourced diamond. You receive a report number that is engraved in your diamond, for you to cross check and match with the certificate. 

Differentiating Real and Fake Diamonds

What is the difference between Real and Fake Diamonds?

Real diamonds, whether natural or lab-grown, are made of pure carbon arranged in a crystal structure, giving them exceptional hardness, brilliance, and durability.

Natural diamonds form over billions of years under high pressure and temperature deep within the Earth, while lab-grown diamonds are created in controlled environments using advanced technology but have the same physical, chemical, and optical properties.

Fake diamonds, also known as diamond simulants, like cubic zirconia and moissanite, may look similar but lack the hardness, sparkle, and refractive qualities of real diamonds.

They are often less durable and can scratch or lose their brilliance over time.

The Four C’s of Diamonds

Every diamond, real or lab-grown, is graded based on the 4Cs:

1. Cut – Determines the diamond’s brilliance.

2. Color – Ranges from colourless (D) to yellow/brown (Z).

3. Clarity – Measures internal flaws (inclusions) and external blemishes.

4. Carat Weight – The size of the diamond.

Lab-grown diamonds at Ananta by Devi Diamonds are IGI-certified and graded using the same 4C standards as natural diamonds.

Conclusion

Verifying a real diamond is a combination of in-home tests and professional validation. While quick tests like the water, fog, and scratch tests provide preliminary indications, the optimal way of verifying a diamond as authentic is to buy one that is GIA or IGI-certified through a good jeweller. 

FAQs

Q1: What is the most reliable way to check if a diamond is real?

Diamond testers are perceived to be an accurate testing tool; however, they only grade the stone based on its hardness and can confuse a simulant with a real diamond. The best way is to get a diamond tested is by a professional jeweller, cross verifying the certificate number engraved in the diamond with the GIA/IGI certificate.

Q2: Can I trust Lab Grown Diamonds Online?

Due to heavy demand in the Indian market, many new brands are entering with attractive half-baked offers. While browsing online, make sure you’re getting international certification (IGI being the best grading lab). In addition, check what kind of Lab Diamond is being sold to you, and from where it is being sourced. 

Q3: Are lab-grown diamonds real diamonds?

Yes! Lab-grown diamonds have the same composition, brilliance, and durability as natural diamonds. There is no difference between the two, both visibly and chemically. 

Find Your Perfect Diamond Today!

Looking for an authentic, high-quality lab-grown diamond? Explore our certified collection at Ananta by Devi Diamonds and make a sustainable, ethical choice.

📞 Contact us today!