Top 5 Best Gemstone Tester

I can think of so many good choices for buying a gemstone tester for daily use. And just in case you’re wondering which is the best gemstone tester to go for. Then your search ends right here.

The article has all the best gemstone testers for your everyday use. Each product is selected after excruciating inspection and thorough comparative research. The final result is a collection of high-quality and premium gemstone testers.

One best gemstone tester that does it all is the Presidium Instruments Gem Tester II. It’s fast, precise, and guarantees efficient and foolproof results.

Keeping the average consumer in mind, I’ve also included a wide variety of gemstone testers in the collection. So you suit different user preferences and expectations.

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Quick Summary

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Top 5 Best Gemstone Tester

# 1. Presidium Instruments Gem Tester Ii – Best Overall Gemstone Tester

Presidium Instruments Gem Tester II (PGT II) Now with Assisted Thermal Calibration (ATC) for Identifying Diamonds/Moissanites and Common Colored Gemstones
  • NOTE: The calibration may be affected during shipping. If you have issues, reach out to the seller.
  • INDUSTRIES MOST TRUSTED gemstone tester redesigned to be more compact, sturdy and portable.
  • THINNEST RETRACTABLE PROBE TIP: PGT II features the industry’s thinnest retractable probe tip.
  • VERSATILE AND RELIABLE: Consistent and reliable results every time. Identifies diamonds/moissanites.
  • SIMPLE & EASY TO USE: Clear and easy-to-read analog dial; Can differentiate 16 types of gemstones.

The Presidium Instruments Gem Tester II is a quick and efficient gemstone tester. It’s one of the most popular ones that you can buy. Offering easy and simple detection based on how the stones conduct heat differently.

The gem tester has a thermo-electric probe. It can be used on any mounted or loose surface which makes it a versatile pick. And it’s convenient and practical enough to analyze different rates of heat repetitively.

So you will find that this gem tester detects thermal-electric conductivity accurately. One more thing about this gem tester that’s delightful is the specially-calibrated dial. It is clear, bright, and authentic for beginner and expert use.

The gem tester features a highly-efficient and thin retractable probe tip. This proves the tester’s portability and its sophisticated durability.

If you ask me, nothing is better than buying this user-friendly and direct gem tester for daily use. It’s one of the best with a proper manual guide and a durable nylon carrying case.

  • Consistent and accurate results.
  • The retractable probe has a thin profile.
  • Perfect for thermal and electric conductivity.
  • Self-calibration required before use.

#2. Smartpro SPGE-I Gem Eye Diamond Tester Pro – Best Gemstone Tester For Pros

SmartPro SPGE-I Gem Eye I Gem and Diamond Tester Smart Pro
  • High efficiency
  • Industry’s thinnest probe tip (0.48mm) for testing diamonds as small as 0.01ct
  • Identifies metals, simulants and diamonds instantly
  • Portable tester that can be used anywhere
  • No waiting time between tests

This is another intelligent gemstone tester with the thinnest and sturdiest probe ever. The benefit of the thinnest probe is that it can detect the tiniest diamond on the market. And the SmartPro can identify diamonds as small as 0.01ct.

You’ll love this diamond tester a lot. It knows how to be accurate consistently. It does feature some complex configurations that a novice might find a bit confusing. But the manual provided in the package explains everything really well.

An effective and tough gemstone tester like this has everything you need. It complements all your gemstone knowledge efficiently. You can find the exact gemstone you’re looking for and analyze it effectively with this.

The tester is very intricate and meticulous. It tells you the difference between different gemstones that traditional gemstone testers couldn’t. Such as blue topaz, aquamarine, pink tourmaline, pink spinel, etc.

The intuitive performance and straightforward interface are worth considering. And it features an efficient USB connection for quick and portable recharging.

Overall, I think you won’t find a diamond tester pro as effective and professional as this one. It competes with high-end gemstone stones smoothly. And if you’re a professional, you’ll love the ergonomics and operation of this one.

  • You don’t have to wait to recalibrate between tests.
  • Portable body with an ultra-thin probe.
  • Identifies multiple gemstones including metals and simulants.
  • Not the easiest choice for beginners.

#3. Presidium Multi Tester III Handheld Instrument – Best Gemstone Tester For Daily Use

Presidium Multi Tester III (PMuT III) All-In-One Instrument for Testing Diamonds, Moissanites and Diamond Simulants
  • IMPORTANT TO NOTE: This product needs to be calibrated prior to use. If you experience issues with calibration, please reach out to the seller for assistance prior to returning the item.
  • EASY TO USE DESIGN: Ergonomic handheld design with a rubberized anti-slip grip for easy handling. Light and portable with a convenient carrying case.
  • THINNEST RETRACTABLE PROBE TIP: Retractable probe tip that ensures consistent pressure against the gemstone during testing for more reliable results. With the industry’s thinnest probe tip size of 0.6mm, the PMuT III tests colorless diamonds as small as 0.02ct.
  • CLEAR, CONVENIENT DISPLAY: 180-degree multi-viewing LED display for easy readability for either right or left-handed use
  • ALL-IN-ONE INSTRUMENT: The world’s first tester that tests for both colorless diamonds and moissanites in a single instrument.

If you trust in Presidium, you know you’re well taken care of. Because Presidium products are minimalist but very practical. They are specifically designed for people who are always traveling.

That is why this handheld instrument is lightweight with a strong and convenient carrying case. It features a retractable probe that offers consistent pressure. No matter how many gemstones you use. You can depend on it.

The Presidium also offers you two ways of keeping it powered. With an AC adapter or using rechargeable batteries. Although you will need to buy the AC adapter separately.

This has something called a “micro-controller” which offers individualized data on various gemstones. Equipped with the thin probe that detects the tiniest stones easily, this is a smart handheld tester for you.

Based on many comparisons, I found that it’s best for using on diamonds and glass. Including different variations of diamond including topaz. It’s also famously used for detecting moissanite. The simple and quick operation ensures that the diamond tester detects quickly and effectively each time.

  • Strong and long-lasting performance.
  • Customized micro-controller for better accessibility.
  • Clear and convenient readability.
  • The power cord is not included.

#4. Presidium SAM Diamond Tester – Best Gemstone Tester For Moissanite

SAM by Presidium, Diamond Tester and Identify a Wider Range of Moissanites
  • Tests Carat Size 0.01 to 10 carats
  • Consistently identifies against a wider range of moisanites, including the new "low electrical conductivity moissanite" made in varous countries.
  • More advanced processing and detection algorithm; Industry's fastest start-up and testing time
  • Highly sensitive thermoelectrical probe capable of identification in a higher resolution; Industry's fastest start-up and testing time
  • Battery life: Approximately 2,000 continuous tests. Easy and Safe to use. Powered via USB or 3xAAA Alkaline Batteries, LED Display; INCLUDES: SAM, Metal Stone Rest, User Handbook, Waranty Card and Carrying Case

The Presidium SAM Diamond Tester is a smart and handheld tester. It features a unique and strong battery life of 2,000 continuous tests. It’s actually the only handheld gemstone tester that is used for a variety of moissanite.

The diamond tester is backed by intricate and customized auto-detection technology. This technology uses efficient electric conductivity and smart algorithm to identify varieties of gemstones.

In fact, this is a thermo-electrical diamond tester with the fastest time ever. It has an easy-to-read interface and a large power button. The dual thermal and electric conductivity ensures smooth performance.

This means that while the tester takes less time to identify different stones. It also is capable of identifying the toughest and rarest of stones with a higher resolution. This makes the diamond tester perfect for experts.

  • Ergonomically handheld gemstone tester.
  • Quick performance and consistent results.
  • Efficient charging time and long battery life.
  • None so far.

#5. Presidium Diamondmate-C Electronic Diamond Tester – Best Gemstone Tester For Diamonds

  • Verifies authenticity of diamonds instantly
  • Thin probe tip (.6mm) for testing diamonds as small as .02ct
  • Retractable thermoelectric probe tip for enhanced accuracy that ensures constant pressure between probe and gemstone
  • No wait time between test
  • Metal alert buzzer

The final verdict on the Presidium DiamondMate-C is that it is an efficient and reliable pick for most people. It is a pocket-sized and convenient tester to use. And it comes with an AC adapter and rechargeable batteries.

This is quite an affordable choice too. It’s a diamond tester which means it doesn’t test other gems. This is probably its only drawback that it doesn’t test other gems including moissanite.

That is why the functionality of this tester is slightly different. It’s fast and dependable, that’s for sure. It perfects the art of analyzing different diamonds – including their variations.

It uses both electric and thermal conductivity to give you effective results. The thermal conductivity ensures less power consumption. While the electric conductivity ensures a fast operation.

Another reason why this best gemstone tester made it to this list is that it features a built-in detector. It makes an audible beep sound as soon as it detects any metal. So you don’t have to worry about anything!

  • Clear and effective results.
  • Smoother than most other diamond testers.
  • The audible beep is distinct and loud.
  • It doesn’t identify other gems.

Buying Guide

Features To Look For In Diamond Tester

Before you buy the best diamond tester for you, there’s a lot you need to re-consider and compare moving forward. These factors of considerations are essential and will guide you in making the right decision based on your personal needs.

Ease of Use

For beginners, simplicity is the first thing that’s a priority. You want to use a diamond tester that’s user-friendly and straightforward to use. No bells and whistles. And nothing that you have to spend hours calibrating and installing before you can start using it.

A diamond tester consists of many important parts. Such as the probe that comes into direct contact with the gemstone. That is why the probe needs regular adjustments and/or replacements and not the whole diamond tester.

When you buy a gemstone indicator with visual or sound indicators, they work right off the bat.

Buying a portable gemstone tester that you can carry with you to auction houses is necessary. You will hardly get people who bring their gemstones to you. So it’s best to look for portability for convenience.


If you had an inaccurate gemstone tester, it’s going to cost you money. So you need to make sure you’re buying the best. A low-quality gemstone tester will interfere with your ability to analyze diamonds effectively.

Look for a strong build and functional design. You can even consider buying a gemstone tester with proper protection. A protective probe tip and a carrying case. These go a long way to ensure that nothing breaks while you carry the tester around in your tool bag.

Battery Life

Buying a battery-powered gemstone tester is the smart choice. Because you get the added convenience of recharging in multiple ways. You can recharge the batteries using a standard power adapter or a USB device.

This improves the portability and durability factor of the tester. Something that you will need if you are traveling with the gemstone tester a lot.


What makes a gemstone tester accurate? Some testers use electrical conductivity to test gemstones.

Traditional gemstone testers use to feature thermal conductivity. But that’s no longer accurate because diamond and moissanite have a very similar way of conducting heat. But the electric conductivity rate between the two stones is noticeably different. So the electric gemstone tester will be able to detect that effectively.

Frequently Asked Questions (FAQs)

What is the best feature of a gemstone tester?

The top feature that makes a gemstone tester accurate is the electric conductivity. You will also find many latest models with thermal and electric conductivity for versatile use.
However, you should also look for a gemstone tester with a built-in metal detector. What a metal detector does is it lets you know when you’re analyzing a metal chunk instead of the actual gemstone.
This is a rookie mistake that a lot of people make. But with a metal detector, you don’t have to.
No metal detector can also increase your chances of detecting a diamond even when it’s not a genuine diamond. The tester will pick up the metal’s analysis and mistake it for a diamond’s. Costing you your time and putting your reputation as a gemstone tester on the line.

What can I use a gemstone tester for?

Jewelers, most dominantly, use a gemstone tester all the time. It is to analyze and inspect the authenticity of a diamond. If you’re a beginner, you need a gemstone tester to understand how it works.
Many gemstone experts hardly use a gemstone tester anymore. They can detect with their eyes and the feel of the diamond, whether it’s genuine or not. However, even an expert will carry a gemstone tester in his or her pocket.
More than for inspection, a gemstone tester is also used to detect what kind of gemstone it is. Different types of stones can withstand pressure and heat differently. So it’s necessary for a jeweler to know exactly what stone he or she is dealing with to proceed with repair or vetting.

How do gemstone testers work?

Everybody knows that different gemstones conduct heat differently. This is exactly what a gemstone tester has to detect to analyze different stones such as diamond or moissanite, etc.
Heat passes in a diamond differently than it does in glass or zirconia. So the gemstone detects using electric or thermal conductivity detects the rate at which the heat passes through the stone.
Gemstone testers that use thermal conductivity use heat which is less accurate than electric conductivity. If you’re unsure about which gemstone tester to buy, you can also buy one that offers both.


A gemstone tester saves you the trouble of wrongly analyzing a man-made synthetic as a diamond. And with it, you have the opportunity to discover a genuine and real diamond when it detects one.

The products you find here are based on evaluation and comparison. After spending countless hours on research and testing, this is the final list of best gemstone testers for most people.

And if you’re looking for something reliable and smart, these popular diamond testers will save the day. The best tester you choose will save you time and money.

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