4 Easy Steps to Use a Diamond Selector II

Do you have diamonds and you can’t tell if they are real or fake? A diamond selector or tester is your go-to tool.

Due to the popularity of and desire for diamonds, it is possible you have heard many ways to check how real or fake a diamond is. But there is no way to test it that is better than using a diamond selector or tester.

Therefore, let me guide you on how to use a diamond selector correctly.

Using a Diamond Selector

There are different types of diamond selectors if you are going to find out if a diamond is real or fake. Bear in mind that many fake ones abound.

But here, I will show you how to use a Diamond Selector II.

Testing a Diamond with a Diamond Selector II

On this diamond selector, you will see a light segment and a knob marked Volume. The knob has Off and On marked on either side of it.

The light segment has numbers under it, from 1 to 8. After number 8, you see DIA, which stands for diamond. These numbers determine the sensitivity you set for each type of stone size. The bigger the stone, the lower the number you start from.

And if a stone is real diamond, the light on the segment will move pretty quickly up to DIA.

A chart at the back of the selector shows you how to set the sensitivity. And there is a metal bar at the back. Keep your fingers on it while testing the stone.

The tip has a rubber cap over it. Remove the cap and you will see the test tip that looks like a needle.

The following are guiding steps on using a diamond selector:

Step 1: Set the Volume or Sensitivity

Set the Volume or Sensitivity

To begin, find the knob on the selector marked volume. Turn it to activate the selector. The Battery OK light will come on.

Wait about 20 seconds for the Ready OK light to come on. Then, turn the knob again until the light on the segment reaches the right spot.

Remember to set the number according to the size of the stone you want to test. The bigger the stone, the lower the number you set. And the smaller the stone, the higher the number you set.

Step 2: Uncap the Selector

Uncap the Selector

As soon as the light comes on, take the rubber cap off the tip of the selector. The cap protects the tip so do this gently.

Place the cap in a safe place so you don’t lose it. There is no other way to protect the fragile tip of the selector.

Step 3: Test the Diamond

Test the Diamond

When the segments light up, press the test tip of the selector on the diamond you want to test. Do this firmly and at a right angle to get the right result. You will need a steady hand.

Just pressing the test tip is enough. Don’t move it on the diamond or you risk breaking it due to the hardness of the gemstone.

While pressing it, keep your hand on the metal bar on the selector’s back. This way, even if you miss pressing the stone and you touch its setting accidentally, it will trigger an alarm to alert you.

Step 4: Interpret the Result

  • If the lights don’t change or move, it means the stone you have is not diamond.
  • And if the lights illuminate slowly and doesn’t read diamond, it means the stone is likely another gemstone like sapphire.
  • However, if the lights exceed 9 on the selector, up to Diamond, it means the stone you have is diamond. All the lights on the bar, from green to red, will light up and there will be a beep.

Put the rubber back on the test tip when you are not using it.

One test may not satisfy you so you may want to run several more to be sure. So I want to point out here that you have to wait to see the light marked Ready come on before you go again.

And it is important I let you know that if you keep running tests on that same diamond, it would become warm.

A warm diamond won’t read correctly so some of the tests may be incorrect. Therefore, allow the diamond to cool if it gets warm before you run more tests.



The sensitivity you use with this selector will depend on the size of the diamond and the weather.

So to set it, turn the Volume knob until the segments light up. Take a look at the number chart on the label of the selector. If the temperature where you are is not cold, set the start number at 4 if you have a small or medium-sized stone. But if you have a large stone, choose 3.

However, if the temperature where you are working is cold, consult the number chart. It will guide you on which segment number to start from.

With time, you will understand how a diamond selector works. You may not even need to consult the number chart anymore if you keep using it.

Important Note

The LED lights are what tell you whether or not the stone you have is a diamond. The starting number does not exactly matter. But it is there to guide you until you grasp how to use the selector.

So if the lights move rapidly, lighting up as they go, you know you have a diamond. This is even if you start at the wrong start number. But if they are slow, you may not have a diamond.

Also, diamonds at different temperatures react differently to the test. If you grab a stone from where direct sunlight hits it, it will react more slowly to heat than one at room temperature. And if the stone is cold, it will react to heat very quickly.

What Is a Diamond Selector?

A diamond selector is a small device used to check the authenticity of diamonds. You can carry it in your pocket; it is that small.

It has a tip that looks much like a needle and is fragile. It is this tip you will place on the stone you want to test.

A real diamond will elicit a beep from the selector or it will show it is diamond on its display.

Some diamond selectors use electricity in the place of heat. A few even combine electricity and heat.

The principle of operation does not change. However, instead of detecting how a stone conducts heat, it detects electricity. This way, it decides whether or not the stone is a diamond.

How Does a Diamond Selector Work?

How Does a Diamond Selector Work
something borrowed

All gemstones don’t conduct heat the same way. So a diamond selector operates based on this principle. If you place a cubic zirconia stone side by side with a diamond, each will conduct heat differently. This is even though they look alike to the naked eye.

Based on this, a diamond selector monitors the manner in which a stone conducts heat and determines whether or not it is diamond.

A diamond is usually cold, temperature-wise. Placing it to your lips will tell you how cold it is. Now, the tip of a diamond selector heats up and when you place it against the stone, the selector checks this coldness by how quickly heat moves through it.

The quicker the heat gets drawn into the diamond, the farther and quicker the lights on the selector move.

Different stone sizes have differing degrees of coldness. Therefore, if a diamond is small, its coldness will be low. That is it will feel more warm than cold. So it will conduct heat slowly.

In the same vein, if a diamond is large, the heat will move quicker. However, the slowness of the movement does not mean it is not diamond. It could just be that the stone is too small.

A cubic zirconia stone, for example, won’t even conduct the heat at all because it is warm. And a large sapphire, for example, may conduct some heat but not much.

Reliability of a Diamond Selector

Despite the fact that a diamond selector is pretty reliable, it can also make mistakes. It cannot tell the difference between a moissanite and a diamond.

This is because a moissanite and a diamond conduct heat just the same. However, they don’t conduct electricity the same way.

Therefore, if you are not sure the stone you have is diamond, use a diamond selector that tests with electricity. This way, you are absolutely sure.


To wrap things up, using a diamond selector involves the following:

  • Setting the sensitivity
  • Uncapping the selector
  • Testing the diamond
  • Interpreting the result

Setting the sensitivity is important but not as important as the speed at which the lights move on the segments. The speed actually tells you whether or not you have real diamond.

I know it looks like a lot right now but trusts me, you will get the hang of it with time. However, if you have any questions, feel free to ask them in the comments section.

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