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Do lab diamonds test as real diamonds: Three tests to know

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If you are here for a quick brief, here’s what you must know:

  • Lab-grown diamonds have identical chemical and optical characteristics to natural diamonds.
  • The naked eye cannot tell the difference between natural and lab-grown diamonds.
  • Even a professional gemologist can’t tell the difference by inspecting the diamond with the naked eye or with a diamond loupe.
  • Lab-grown diamonds do pass a diamond tester, however there is a way to tell the difference; only gemological labs have the right equipment.
  • Standard Diamond Tester: It’s a pen-sized device measuring heat and electric conduction to determine if a gemstone is a real diamond. It can’t differentiate between natural and lab-grown diamonds.
  • UV Ray Test: A specific detector that tests the gemstone’s reaction to UV rays can differentiate between natural and lab-grown diamonds.
  • Fake Diamonds: Cubic zirconia and glass are considered fake but can be detected with the right technology. Lab-grown diamonds are not considered fake.
  • Moissanite vs. Lab-Grown Diamond: Moissanite is a synthetic gem with a hardness level of 9, while lab-grown diamonds rank 10 on the Mohs’ scale.
  • You can detect lab-grown diamonds by checking the certificate, inspecting the girdle, or sending it to a gemological lab to determine if a diamond is lab-grown.
  • Doesn’t matter if you go with a natural or a lab-grown diamond, make sure to buy it from a reliable seller such as this one with a GIA certificate or this one that offers both GIA and IGI-certified diamonds.

Test yourself: Is this diamond natural or lab-grown?

Table of Contents

Do lab-grown diamonds pass a diamond tester? Do lab diamonds test as real? Can we distinguish between them? This article will cover three tests that will answer these questions, one set for all.

Let’s start.

Lab diamond test: How a standard diamond tester work?

The most common tool in the market is this simple diamond tester. It’s a portable device in a size of a pen. You might have seen it already on Youtube videos or at your local jewelry store. All it does is measuring how well the gemstone conducts heat and electric conduction. This way, the tester can tell you if the diamond is a real diamond or not.

Does it mean that this diamond tester can differentiate between natural diamonds and lab-grown diamonds?

No, it can’t. Since lab-grown diamonds share the same physical and chemical properties as natural diamonds, they also have the same electrical conductivity and thermal conductivity properties. For that reason, both share the same result: REAL.

Lab diamonds are real diamonds. The only difference is their origin.

But still, is there a way to differentiate between the two? Yes.

lab grown diamond tester

What is a lab-grown diamond?

Lab-grown diamonds, also known as lab-created diamonds, are grown in highly controlled laboratory environments using advanced technological processes that duplicate the conditions under which diamonds naturally develop when they form in the mantle beneath the Earth’s crust. These lab-grown diamonds consist of actual carbon atoms arranged in the characteristic diamond crystal structure. Since they are made of the same material as natural diamonds, they exhibit the same optical and chemical properties.

Are lab-grown diamonds as hard as natural diamonds?

Since lab-grown diamonds share the same chemical and physical characteristics as natural diamonds, they are as hard as real diamonds, also known as earth-created and natural diamonds.

Lab diamonds test with a naked eye: Can a jeweler tell if a diamond is lab-grown?

If a jeweler uses only the naked eye, there is no way to spot the difference. Even most diamond experts can give the wrong answer. However, a professional shouldn’t trust the naked eye. A reliable jeweler should send the diamond to a gemological lab that has the right equipment.

Test: is this diamond natural or lab-grown?

Lab diamonds test under UV rays

The most reliable way to determine whether a diamond is natural or lab-grown is to use a machine called “Sherlock Holmes CVD and HPHT detector” from Yehuda Diamond. To simplify, it tests how the rock reacts to UV rays. By measuring the fluorescence of the gemstone, the lab can determine if it is a natural diamond, lab-created, or any other type of rock.

This is the most reliable test, but since this machine is not cheap and costs around $6,000, most local stores don’t own one. The first tool costs only $20 on Amazon, but it’s not reliable, and even can test moissanite as a diamond. If you want to check your stone, ask the jeweler to send it to a lab with the right equipment.

Are lab diamonds worth it?

Let’s compare lab diamonds and natural diamonds’ resale value. After watching this video, you’ll have your answer whether lab diamonds worth it or not.

Can you tell the difference between a lab diamond and a real diamond?

An untrained diamond consumer cannot tell the difference between lab-grown and natural diamonds. High-quality lab-created diamonds are identical in look to natural ones, which leads us to the last lab diamonds test: the certificate. By inspecting the diamond report, you can immediately know if it’s natural or lab-grown. Moreover, it would be best if you examined the diamond’s girdle with a loupe. If the diamond were graded by a trusted lab such as the GIA or the IGI, they would carry an engraved serial number over the girdle. If it’s a lab-grown diamond, they must mention it.

Don’t see any serial number? Don’t risk your money. This diamond is uncertified, meaning you cannot know if it’s even real or fake.

What fake diamonds pass diamond tester?

First, it’s important to mention that lab-grown diamonds are not considered as fake. On the contrary, they are as real as natural diamonds since they share the exact chemical, optical and physical properties. The only difference is the origin.

When referring to a stone as a fake diamond, most customers talk about cubic zirconia (CZ) and glass.

Cubic zirconia is a cubic, crystalline form of zirconium oxide and is often used as a diamond simulant. It belongs to the family of synthetic gems that are also called fashion or costume jewelry.

Glass, on the other hand, is not gem quality: it’s an artificial material with no perfect cubic crystal structure. As a result, it has inferior optical properties when compared to diamonds (like double refraction).

So what fake diamonds pass diamond tester? None. As long as the jeweler uses the right technology, it’s possible to spot diamond simulants right away.

CZs of high quality can look like natural diamonds without flaws, while lab-grown ones might show inclusions if magnified.

Can you tell the difference between moissanite and lab-grown diamond?

Moissanite is made of silicon carbide and belongs to synthetic gems called fashion or costume jewelry. While lab-grown diamonds have the highest grade in the Mohs’ scale of hardness, 10-grade moissanite has a hardness of only level nine.

If we test how moissanite conducts heat, we might get a wrong result: it will test as a diamond. But by checking the electric conduction, we will find out its moissanite and not a diamond. Then, same as with natural and lab-grown diamonds, we can send the moissanite to a lab and test how it reacts to UV rays. In that case, we won’t have any doubt; it will immediately show its moissanite and lab created diamond.

Are lab-grown diamonds GIA certified?

The GIA is the most famous institute in the diamond industry known for its grading and creating certifications of natural diamonds. Lately, It has started doing the same with lab-grown diamonds. However, GIA-certified lab diamonds are not very common. Their price is much higher than other grading labs. Therefore, most sellers will prefer to pay the IGI, AGS, or GCAL certificate and keep costs low, which is not bad because it means that you’ll get a more affordable diamond.

>> Read more about lab diamonds certifications here << 

How can you tell if a diamond is lab-grown?

To summarise, there are three ways to tell if a diamond is lab-grown:

  • Check the certificate: The grading lab must mention the origin of the diamond if it’s natural or lab-grown.
  • Inspect the girdle of the diamond: All certified diamonds carry an engraved serial number over the girdle. In case it’s a lab-grown diamond, the lab engraves it as well right next to the serial number.
  • Send it to a gemological lab: Using the right technologies, such as testing how the diamond reacts to UV rays, the lab ables to tell if it’s lab-grown or natural.

Should you buy a diamond without a certificate?

You should never buy a diamond without a certificate. Even if the seller offers you the best deal in the world, it should only raise a red flag.

What you see is not what you get:

  • You can’t know the diamond’s origin: Is it real or fake? Is it stolen?
  • You can’t know the real color
  • You can’t know the real clarity
  • You can’t know the real carat weight
  • You can’t inspect the cut level, which affects the brilliance and sparkle of the diamond

Conclusion - Do lab-grown diamonds pass a diamond tester?

Yes, lab-grown diamonds do pass a standard diamond tester. Since lab-grown diamonds share the same physical, chemical, and optical properties as natural diamonds, they also have the same electrical and thermal conductivity properties. As a result, both lab-grown and natural diamonds will register as real on a standard diamond tester. The only reliable way to differentiate between the two is through specialized equipment and methods such as UV ray testing or sending the diamond to a gemological lab with the right technology. Therefore, a conventional diamond tester is not sufficient to distinguish between lab-grown and natural diamonds.

There are ways to know if a diamond is lab-grown or natural. But, in the end, what matters the most is what gives more value to your money and what will make your significant other happy. So pick the right diamond for you; the origin doesn’t matter.


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Author: Yaniv Hadar

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