How to Tell if a Diamond is Real or Fake?

The world values diamonds as among its most valuable and precious gemstones. It becomes crucial to determine diamond authenticity whether you have a ring with diamond pendants or loose stones.

The most dependable method to verify a diamond relies on professional jewelry expertise; however, several basic tests exist for home verification. This piece presents various strategies together with step-by-step instructions to detect authentic diamonds.

Key Takeaways

You will know what the real physical and chemical characteristics of diamonds are.
Explore the various ways you can test if a diamond is real or fake.
You will also get an idea of what approach you should follow when all the tests fail.

Physical and chemical characteristics

Characteristic	Real Diamond
Hardness	10 on Mohs scale (hardest natural material)
Density	3.5–3.53 g/cm³
Refractive Index	2.42 (very high, causes strong sparkle)
Thermal Conductivity	Extremely high (spreads heat quickly)
Electrical Conductivity	Insulator (except for blue diamonds, which conduct electricity)
Transparency	Transparent but may have natural inclusions
Luster	Adamantine (brilliant and shiny)
Cleavage	Perfect in four directions (can break along these planes)
Fluorescence	Some diamonds glow blue under UV light
Crystal Structure	Cubic (isometric)
Composition	Pure carbon (C)
Reaction to Heat	Does not burn or melt easily; turns to CO₂ at extreme heat (over 850°C in open air)

1. The Fog Test or Breath Test

You can perform the fog test as a simple way to determine if your diamond is genuine. Observing rapid fog clearance after breathing on a stone will reveal its authenticity because diamonds serve as superior heat conductors along with their moisture-resistant properties.

How to perform the fog test:

Wash the diamond to eliminate surface debris along with oil residue.
Set the diamond near your open lips to exhale breath onto it in the same manner as you clear a mirror with breath.
Note down how fast the fog vanishes from the diamond.
The diamond shows signs of authenticity if the fog dissipates right away during the test. A fake stone may be present when fog appears to remain on the stone for several seconds during testing.

2. The Water Test or Floating Test

The Water Test or Floating Test of diamonds

The water density test serves as a simple method for determining whether a diamond is genuine.

How to perform the water test:

Take a glass of water.
Put the loose diamond under the surface of the water.
A diamond that sinks toward the bottom of the glass water shows signs of being authentic since gemstones carry substantial density levels.
A fake diamond usually stays on the water's surface after floating.

NOTE: This method works exclusively for loose stones because diamond mountings affect the measurement results.

3. The Loupe Test

When examining diamonds, jewelers rely on the specialized viewing instrument called a loupe. This equipment enables professionals to detect diamond features within its interior.

How to perform the loupe test:

Acquire a jeweler’s loupe or an alternative magnifying glass.
Use adequate lighting to analyze the diamond.
Real diamonds normally contain small imperfections, which experts refer to as inclusions.
The total perfection of a diamond without any imperfections should raise suspicion about whether it is real or made in a lab.

4. The Fire Test

The diamond heat resistance test determines how diamonds respond to temperature fluctuations. Natural diamonds remain unaffected by extensive temperature fluctuations.

How to perform the fire test:

Use metal tongs to grip the diamond.
Check damage by subjecting the diamond to a lighter or candle flame for thirty seconds.
Place the diamond directly into cold water after the test.
Real diamonds survive exposure to temperature changes, but artificial diamonds often break because of the sudden change in temperature.

Warning: Users must exercise extreme caution with fire during this assessment process since fire handling poses safety risks.

5. The Refractivity Test

$The Refractivity Test of Diamonds$

Light passes through diamonds with powerful refraction, which results in fantastic sparkle. Artificial diamonds fail to show lighting effects comparable to authentic diamonds.

How to perform the refractivity test:

Newspaper Method: For the newspaper test set, place the diamond stone facing down on top of a printed newspaper. A diamond that shows newspaper print during this test may be an artificial stone. Real diamonds disperse light while scattering it along a wide path, which blocks the newspaper print from view.

Dot Method: Draw a dot on a white piece of paper and place the diamond over it. The diamond's fake nature is indicated when you can spot the dot beyond its edges. True diamonds redirect light in various directions until the spot becomes invisible.

6. The Scratch Test

A diamond stands as the most durable natural substance that shows resistance to any scratching attempts.

How to perform the scratch test:

Put a glass piece before attempting to scratch it with a diamond.
The glass will show signs of scratches without causing any damage to the diamond, which points toward authenticity.
The identifying test for diamonds is inconclusive because fake materials such as moissanite can possess similar high levels of hardness.

7. The Thermal Conductivity Test

This examination of diamonds proves efficient because they rapidly transfer heat.

How to perform the thermal conductivity test:

A thermal conductivity tester available in stores helps with this evaluation process.
Set the probe directly on top of the diamond surface.
A diamond shows signs of being real if it dissipates heat immediately. A fake diamond tends to hold heat for an extended period of time.

8. The Black Light or UV Test

When subjected to ultraviolet (UV) light, certain diamonds produce visible glows.

Put the diamond underneath a black or ultraviolet light source.
Most real diamonds emit a blue fluorescence.
If it glows green or yellow, or does not glow at all, it could be fake. However, not all real diamonds glow, so this test is not conclusive.

9. The Magnet Test

Diamonds do not stick to magnets. So, if you have any magnet in front of you, give a try to this particular test. This test helps find fake ones.

How to perform the magnet test:

Take a strong magnet.
Hold it near the diamond.
If the stone moves towards the magnet, it is fake.
If it does not move, it could be real or another fake stone that is not magnetic.

10. The Flashlight Test

Real diamonds shine in a special way. The edges and refractive index of real diamonds cause light to be scattered in a particular special way.

How to perform the flashlight test:

Shine a flashlight on the diamond.
A real diamond will shine bright white and show rainbow colors.
A fake one may not shine much or look dull.

11. Check the Jewelry Setting

The way the diamond is set in jewelry can give a clue.

How to check:

Real diamonds are placed in strong metals like gold or platinum.
Look inside the ring band for marks like "14K," "18K," or "PLATINUM."
If the metal looks cheap, the diamond is probably fake.

What If Your Diamond Fails a Test?

If your diamond does not pass a test, try other tests. If it fails many tests, it may be fake.
The best way to know is to ask a professional jeweler. If you want some authentic confirmation, you should spend some time on the internet and find out the dealers near you who perform a diamond quality check.

We, at Earth Shine Jewels, know exactly the professional techniques of checking the quality of a diamond. Besides, we also provide certification based on which you can sell the diamond at a better price in the future.

How to Buy a Real Diamond?

To make sure your diamond is real:

Buy from a trusted jewelry store.
Ask for a certificate from GIA or another expert group.
Check its shine, cut, and quality.

It is important to know if a diamond is real or fake. Professional testing is the best way. But these simple tests can help at home. If you are not sure, always ask a jeweler.

You should always get your diamonds checked and verified by credible jewelers. This will help you to get the best resale value in the future.

FAQs

1. How can you tell if a diamond is real at home?
Drop the diamond in water. A real one sinks, but a fake one may float. Breathe on it, and if it clears quickly, it is real. Hold a strong magnet near it. If it sticks, it is fake. Shine a flashlight on it. A real diamond will sparkle brightly. Check the metal setting. Real diamonds are usually set in gold or platinum. If you are not sure, ask a jeweler.

2. Can I test a diamond with my phone?
Yes, you can. Shine your phone’s flashlight on the diamond. A real one will shine brightly. Use your phone’s camera zoom to look closely. A real diamond usually has tiny flaws. You can also heat the diamond with your flashlight. A real one won’t heat up fast. These tests help, but they are not always accurate. A jeweler can confirm if it is real.

3. How to tell a real diamond by flashlight?
Shine a flashlight on the diamond. A real diamond will sparkle with bright white and rainbow colors. A fake one will look dull and not shine as much.

4. How to identify a raw diamond at home?
Try scratching glass with the stone. A real diamond will leave a scratch. Shine a UV light on it. Some real diamonds will glow blue. Drop it in water. A real diamond will sink quickly. Heat the stone with a lighter, then put it in cold water. A real diamond will not break. If you are still not sure, take it to a professional.