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Diamond Tester: Top Reasons For You To Own One!

A diamond tester is what you will long to pay for after going through this article.

You can easily discover various types of diamonds in the market like Pink diamonds, Black diamonds, Yellow diamonds, Red diamonds, etc. All these variants are extremely rare and not available everywhere on the Earth. And even if they’re, there are minimal chances of them being genuine. 

Thus, there are chances that you might end up owning a “fake” diamond that might appear 100% real to the naked eye, but it won’t be in real sense. And the best way of determining whether yours is a real stone or not, you can make the use of a diamond tester. And this is what the article is based on. In this post, you will learn:

What is a diamond tester?

A diamond tester is a portable device that tests whether the diamond is natural and real or not, by measuring the amount and speed with which heat and/or electricity travels through the stone. This is based on the fact that how heat or electricity travels through a real diamond differs from that through its imitates like moissanite, ruby, sapphire, etc.

How does a diamond tester work?

The working principle of a diamond tester is based on the evidence that different gemstones exhibit different conduction properties, be it heat or electricity. It has a small, needle-like tip that is to be placed on the stone to be tested. It then causes heat or electrical transference and measures the rate at which conduction takes place. If the tester uses heat for this purpose, it’s called a Thermal diamond tester, and if it utilizes electricity, it’s termed as an Electrical diamond tester. These are extremely accurate and display the results in no time.

Which is better: Thermal testers, Or Electrical testers?

If you’re going to buy a diamond tester, you should know which one is better than the rest. According to the gemologists, an electrical diamond tester is better than a thermal one. It’s because although the electrical tester will cost you more, it’s highly accurate than the more economical thermal tester. 

Furthermore, there’s a special type of synthetic diamond, Moissanite which can “only” be detected using electrical conductivity as it conducts heat in a similar manner as a real diamond. Hence, it’s better to pay for an electrical diamond tester.

What are the other ways to test for a real diamond?

If in case, you don’t have the luxury of a diamond tester, you can try the following home tests for the same purpose.

Fog test

Hold the stone in front of your mouth and breathe out on it. If it’s real, the fogginess would disappear immediately as it’ll disperse the heat more quickly. In case the diamond is fake, the stone would still appear foggy. 

Dot test

Draw a dot on a white paper and place your diamond on it. If the dot is visible through the stone, it’s a fake diamond.

Water test

Drop your diamond in a glass of water. A real diamond, due to its high density, will sink straight down to the bottom of the vessel, else it’ll stay afloat in case it’s fake.

How to properly use a diamond tester?

Although there’s no rocket science behind using a tester, you should go through its instructions manual before using it. Or, you can take note of the following instructions.

  • Ensure the diamond to be tested has a clean surface.
  • Place the needle tip at no less than 90 degrees on the surface.
  • Don’t press the tip too hard on the stone. It may damage the diamond tester and your diamond too.
  • In case you’re testing jewelry, make sure to hold the tip on the stone and not on the surrounding metal.
  • The stone should rest on a stable surface else the reading may vary. 

Taking these precautions while testing will generate the most accurate results.

What are the helpful features of a diamond tester?

With technological advancements, diamond testers are getting upgraded with more useful features. For instance, most of the modern testers are equipped with a metal detector that will alert you in case the tip is touching the surrounding metal. You will find testers with a high-tech digital display that’ll display every minute information regarding the piece. Additionally, some high-end expensive models come with a magnifier that allows you to magnify the stone for a closer look at the possible blemishes or irregularities if any.

Since a tester is a portable device, you will love carrying it outside in your pocket. Right? So, you can go for battery-based models that don’t require electricity to function. 


How reliable is a diamond tester?

You would be surprised to know that a tester is a highly reliable device to determine the authenticity of a diamond. However, there might be a situation in which the device may display inaccurate results. This generally happens with a poor brand tester that lacks the basic features. Hence, always go for a branded tester for high reliability.

Can a diamond tester test other gemstones too?

Yes, a diamond tester can also be used for other stones like ruby, moissanite, sapphire, jadeite, crystals, etc.

Do real diamonds shine in the dark?

No, a real diamond won’t sparkle in the dark as it requires a source of light for this. It then absorbs the light and reflects it through the cuts for brilliance.

How much does a diamond tester cost?

Depending upon the brand, making, design, feature set, and other factors, you can expect a diamond tester in the range between $99-$699.

Under what circumstances does a diamond tester display fake results?

There could be many reasons behind it. For example, the battery of the device may not be full, the tip is not properly placed on the diamond, a thermal tester is being used with a moissanite, etc. 

Diamond Education

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