There are many types of diamond testers available in the market today. Earlier the only option was the thermal tester but now with the advent of technology, many new types of electrical, UV induced and many others are available in the market in different price ranges. Read on to know more about what is a Diamond tester and can it be wrong?

What is a diamond tester?

Diamond Tester is a portable device that helps test diamond in a go, it is so small that it can be put in your pocket. The tester is a small, needle-like tip that needs to be placed on the diamond to be tested. If the diamond is real, the device indicates that on its display or with a beep-beep sound signal. They are a little hand-held device (there are some big ones too for the desk and with even more technicality!) that tests for both the Thermal Conductivity and the newer ones also test for Electrical Conductivity (for distinguishing Moissanites from Diamonds).

How does a diamond tester work?

The old Diamond Testers have a metal tip that is heated and then applied on the comparatively cooler surface of a diamond. Heat transfer occurs and the diamond surface is heated by the tip. If the heat reading of the testers and the diamond match, this indicates that the stone really is a diamond. It is based on a principle of operation that is based on the fact that different gemstones conduct heat differently. Heat would pass a diamond differently than it would through cubic zirconia or glass or as a matter of fact any other gemstone. A Diamond Tester can’t be wrong, will detect the rate at which the heat moves through the stone. The new electrical devices are also available in the market today.

Types of diamond testers

There are various types of Diamond Testers available in the market today. The conventional heated tip method is largely being replaced by other methods of conduction or a modification. In the case of Synthetic Diamonds, the most viable option is the Electrical method or the UV testing Method.

1. Thermal diamond tester

The Conventional or Thermal Diamond probe consists of two thermistors (semiconductor devices with resistance characteristics and very high levels of sensitivity) and a small copper tip in a holder. This is a conventional type of tester where the needle tip is heated and the probe put on the surface of the diamond. The high-temperature sensitivity makes it an accurate and reliable device. The instrument is very delicate and needs to be handled with great care. One type is Ceres Diamond Tester, you can trust.

2. Electrical conductivity diamond tester

It works on a similar principle as the conventional heat diamond testers. It’s just that electricity is used instead of heat. Moissanite testing is done mostly through electricity as Moissanite is electrically conductive.

3. The diamond tester pen

The GIA pen is a tool that operates on a different property of diamonds to differentiate good ones from the less genuine kind. As per the GIA, Diamonds express a certain affinity for grease and greasy liquids. The pen-like Fountain pen contains a particular type of greasy liquid that will leave visible marks on otherwise nonabsorbent diamond facets. This liquid, if placed on any other stone facets will bead up without leaving a distinct image of any kind.

4. Fluorescence diamond testing

This type of testing is done especially for Synthetic Diamonds. All diamonds have some measure of fluorescence, on a scale of one to five- one being too little and five being strong fluorescence. It is difficult with multi diamond jewelry, to the fluorescence scale as the fluorescence will differ from stone to stone. Only with synthetic diamonds, this consistency is possible.

5. Diamond indenter hardness tester

The Indenter Hardness Test is generally easier to perform and more accurate. It can be used except in conditions where the test metal structure or surface conditions would introduce too many variations; where the indentions would be too large for the application; or where the sample size or sample shape prohibits its use. This method measures the permanent depth of indentation produced by a force/load on an indenter. One of the best devices as Diamond Indenter Hardness Tester is The Rockwell Method.

How to use a diamond tester at home?

In the case of Thermal Testers,
● Always properly clean the stone before testing
● Gently remove the protective cap from the probe tip.
● Hold the diamond tester in your right hand, with your index finger touching the electricity-conducting panel on the top of the diamond tester.
● Press the probe tip at a right angle (see example) onto the top of the stone. Do not press the tester to a stone at an angle of fewer than 90 degrees.

CAUTION: Too much force may break or bend the probe tip!
● When testing stones that are already mounted, hold settings with your left hand.
● For loose stones, the best results occur when the stone is placed in the testing base. Secure testing base with one hand.

Diamond tester price

You can find a normal thermal diamond tester ranging from $13-$20
Moissanite Testers are available from the range of $22-$30
Jeweler Diamond kit is available from $36-$40
(All the above prices are based on eBay Product Prices)

Diamond tester app for android

Now all the android users and ios users can benefit from GIA’s free interactive diamond app for consumers and retailers, available in English and simplified Chinese. This app also has interactive features like video content and information on GIA created 4Cs (Color, Cut, Clarity, and Carat) of diamond quality.

“Bringing objective information about gems and jewelry to people when and where they want it is central to GIA’s public-benefit mission,” said Kathryn Kimmel, GIA vice president, and chief marketing officer. “The Android 4Cs app puts GIA’s 82 years of innovation and research right on the screens of the most widely used smartphones in the world.”

Users can also identify inclusions if any in the diamond and learn about how a cut can make a significant difference in the look of the diamond. The app provides direct access to GIA Report Check, a secure online database of GIA Grading Report Check, a secure online database of GIA- where users can email, tweet, share on facebook their personal diamond wishlist. There are other apps available on Google Play Store too like DGuard Diamond Testing.

Can a diamond tester be wrong?

Diamond Testers can be failed in many ways and they are not always perfect inaccuracies. The few basic reasons why they can fail are:
– The Battery must be dying
– You accidentally hit a prong
– The Diamond could be a Moissanite
– The tip could be loose, bent or worn down
Moissanites aren’t detected by heat detectors, it is electrically conductive so you must take two checks before you buy a diamond. It is advisable to do so, so the probability of genuinely rises.

What are diamond testers?

A diamond tester is a portable device that you can put inside your pocket too. The tester has a small, needle-like tip that needs to be placed on the stone that is to be tested. It tests the authenticity of the diamond, if the diamond is real, the device indicates that on its display or with a sound signal.

How it really works?

The principle of its operation is based on the fact that different gemstones conduct heat differently. The heat will pass through a diamond in a different way than it would through cubic zirconia or glass. A diamond tester detects the rate at which heat moves through the stone and says to you whether it is a real diamond or a fake one. There are also testers that use electrical conductivity to test stones – they are based on a similar principle, but they use electricity instead of heat.

What are diamond testers used for?

Diamond testers are used by jewelers to keep a check upon the quality of the diamond. If you try to sell it or exchange it for another one, the jeweler forts test if your stone is a real one or not. Even when you take your piece for repairing to a jeweler, it is mandatory for a jeweler to know what the stone in the setting is since different gemstones absorb heat, pressure, and stress differently. Diamond tester used to check the quality of the diamond and it can’t be wrong.

It’s your duty, to make the person who repaired your diamond jewelry test the stones in front of you when you go for receiving them.
In case, if you are in qualms that the gemstone you have is a real one or not go to a jewelry store and get your stone tested.

How reliable are diamond testers?

Diamond testers are one of the most accurate tools to check a diamond for its authenticity. However, testers that depend upon thermal conductivity can mistake moissanite for a diamond because these two stones are very similar in the way they conduct heat. Diamond testers are the most reliable tool, however, we should also be good handy to take care and diamond tester can’t be wrong while testing a diamond.

This problem is solved by using a device that uses electrical conductivity to test stones – diamonds and moissanite conduct electricity differently.

What makes a good diamond tester?

Make sure that the device uses electrical conductivity in order to tell a diamond from moissanite. The latest models available on the market combine heat/electricity testing making it more accurate. Its second important feature is that it has a metal detector that signals if you accidentally touch the part of the metal setting instead of the stone. If your tester doesn’t recognize metal, it can indicate that you are holding a real diamond when you unknowingly touch the setting, even if the diamond itself is fake.

Here are 5 best diamond testers.

1. Presidium diamond mate tester (PDMT- C)

It figures out the authenticity of diamonds instantly and works on both polished and unpolished gemstones. This diamond tester is capable of testing diamonds as small as 0.02 carats. It provides consistent, accurate results. In fact, there are numerous positives when working with the Presidium Diamond Mate Tester (PDMT- C):

The display is good and visible,the diamond tester also comes with a protective carrying case, carry it in your pocket with ease (and without worry about damaging the diamond tester) The Presidium Diamond Mate Tester (PDMT- C) quite handily determines if a gem is a diamond based on its thermal properties.

2. Lucky stone diamond tester

It is a kind of a detector that is extremely effective in distinguishing between metal and stone. It makes a continuous buzzing kind of sound if you accidentally touch metal instead of stone.

The lucky stone jewelry diamond tester selector II

The tool delivers accurate readings as a result. It has an easy-to-read LCD display and LED indicator that works this way: real diamonds cause the light to turn green fake diamonds don’t get a reaction from the light indicator This diamond tester also has a large/small switch that tests diamonds at +/- 8 points. It operates on one DC 9V battery, but you’ll have to buy one separately.

3. HDE High accuracy professional jeweler diamond tester for novice and expert

Featuring a low battery indicator for accurate readings, this tool could be the best diamond tester for many jewelry buyers. It gives sounds to distinguish between different readings. The diamond tester has small and large switches for testing diamonds. It requires one 9V battery to operate.

The HDE high accuracy professional jeweler diamond tester

It can be used by both for Novice and an expert too. It comes in a leather storage case. This storage case protects it while it’s not in use. It also enables you to take the diamond tester with you when you’re shopping. The HDE High Accuracy Professional Jeweler Diamond Tester also comes with a small testing tray.

4. Diamond Tester II V2 selector gemstone jewelry gems tool with case

This portable diamond tester provides fast, accurate, and safe testing to determine if a gem is a diamond. It features an LCD display and an LED indicator. The tool does not emit any sort of reaction when a stone is detected fake. When the light remains green, that means the gem is a real diamond. The Still Cool diamond tester emits signs that are audible enough to assist with accurate testing. Diamond tester II is also one of the easiest tools to check the quality of the diamond even if it is wrong or not.

5. Btkuon 3in1 diamond gemstone tester selector II gems tool test +60x LED microscope magnifier

The 3in1 Diamond Gemstone Tester Selector II is one of the best diamond testers that includes a microscope. The LCD display is easy to read for more accurate results. The Btkuon diamond tester has an energy-saving auto-off function. In case you forget to turn it off, this is helpful. It turns the diamond indicator’s light green if the gem is a diamond. Also, the diamond tester also comes with a protective leather case so it lasts longer. Diamond Gemstone Tester is one of the great tools to check the diamond whether its wrong or not.



Q 1 What is a diamond tester?

Diamond tester is a tool, that helps to test a diamond. It indicates that the diamond is real on its display or with a beep-beep sound signal.

Q 2 Can a diamond tester be wrong?

Yes, the diamond tester can be wrong.

Q 3 What are the types of diamond testers?

Thermal diamond tester, Electrical conductivity diamond tester, The diamond tester pen, Fluorescence diamond testing, and Diamond indenter hardness tester.

Q 4 What makes a good diamond tester?

The device uses electrical conductivity in order to tell the diamond is real or not. Diamond tester, should have a metal detector that signals if you accidentally touch the part of the metal setting instead of the stone.

Author Anupama Singh

Besides wealth and health, learning, teaching, and cooking are my interests in life. I have a bachelors in engineering and an unbeatable streak of optimism, come what may! I love to learn new things! Hope you do too.

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