10 Best Diamond Tester of 2026

Last updated on 04/14/2026
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Best Choice
1
9.9
Exceptional
Save 8%
Valkynos Diamond Tester Kit with 60X Loupe & UV Light, Thermal Conductivity Diamond Tester Pen for Real Diamonds, Detects CZ, LED & Audible Alert, Tests Small & Mounted Jewelry (2pt / 0.02 ct+)
Valkynos

Valkynos Diamond Tester Kit with 60X Loupe & UV Light, Thermal Conductivity Diamond Tester Pen for Real Diamonds, Detects CZ, LED & Audible Alert, Tests Small & Mounted Jewelry (2pt / 0.02 ct+)

8% Off
Why we love it
  • Fast accurate diamond verification.
  • Tests small mounted diamonds.
  • Portable complete testing kit.
Main Highlights
  • 【FAST & ACCURATE DIAMOND TESTER KIT】-- This professional diamond tester pen uses advanced thermal conductivity technology to accurately identify real diamonds and distinguish them from common simulants such as cubic zirconia, glass, and crystal. Ideal for home users, collectors, resellers, and estate jewelry inspection.
  • 【IMPORTANT LIMITATION – NOT FOR MOISSANITE】-- This tester works based on thermal conductivity and cannot reliably distinguish moissanite, which has similar thermal properties to natural diamonds. Designed for basic diamond authentication, not electrical conductivity testing.
  • 【TEST SMALL & MOUNTED DIAMONDS】-- Accurately detects diamonds as small as 2 points (0.02 ct). Suitable for testing loose stones and mounted jewelry such as rings and earrings. For best results, avoid metal interference when testing set stones.
  • 【UV FLUORESCENCE & CLEAR INDICATORS】-- Built-in 365nm UV light provides additional reference by revealing fluorescence in some diamonds. Bright LED indicators and audible alerts deliver fast, easy-to-read results, making testing simple for beginners and professionals alike.
  • 【COMPLETE & PORTABLE TESTING KIT】-- Includes diamond tester, a 60X magnifying loupe, protective carrying case, and 9V battery included—ready to use out of the box. Compact and travel-friendly. Backed by 30-day unconditional return or exchange and responsive customer support.
9.9
Exceptional
Save 8%
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🛡️Trusted by 100M+ UsersWhy?
Best Value
2
9.8
Exceptional
Valkynos Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor – Fast 0.5s Detection, Portable Gem Checker for Novice & Experts – Battery Included
Valkynos

Valkynos Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor – Fast 0.5s Detection, Portable Gem Checker for Novice & Experts – Battery Included

Why we love it
  • Fast and accurate diamond verification.
  • Built-in UV light for assessment.
  • Compact and travel-friendly design.
Main Highlights
  • After-Sales Service: 30-day unconditional return or exchange. For any issues or battery replacement (same type available in the U.S.), please contact us
  • 【Fast & Accurate Diamond Verification】The high-accuracy diamond tester pen has advanced thermal conductivity; this tester accurately distinguishes real diamonds from common fakes like crystal or cubic zirconia. Ideal for home use, collectors, or resellers
  • 【Built-in UV Light for Fluorescence Detection】Diamond tester professional features a built-in UV light to reveal diamond fluorescence—an important clue in verifying authenticity. Different materials show different reactions under UV, making this feature useful for deeper assessment
  • 【Real-Time Feedback with LED Lights & Sounds】After a 25-second warm-up, hold the conductive panel on the top with your finger, tip the vertical diamond 90 degrees: a red LED flashes and a buzzer sounds when a real diamond is detected
  • 【Testing Tips for Best Accuracy】✦ Use with bare hands (avoid gloves)✦ Best results at room temperature (10–35°C)✦ Accurate for diamonds 0.02 carats and larger
  • 【Compact & Ready for Travel】Diamond tester pen compact size with protective case makes it easy to keep in your bag or drawer, leather pouch keeps your tester safe— perfect for on-the-spot diamond checks at home, in stores, or while traveling.
9.8
Exceptional
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3
9.6
Superb
GemOro UltraTester 3+ Diamond Tester | Test Diamond, Moissanite, White Sapphire Gemstone | Precision Tool with Expert Professional Reading & Accuracy
GemOro

GemOro UltraTester 3+ Diamond Tester | Test Diamond, Moissanite, White Sapphire Gemstone | Precision Tool with Expert Professional Reading & Accuracy

Why we love it
  • Accurate stone identification technology.
  • LED illumination enhances testing clarity.
  • Versatile power options for convenience.
Main Highlights
  • STONE IDENTIFICATION: This new enhanced testing technology is a breakthrough in the identification, detection, and separation of diamonds from other materials such as CZ, moissanite, and white sapphire. This technology has the capability to identify stones with low conductivity, allowing accurate detection and separation of diamonds from other materials. It evaluates stones using cutting-edge scanning techniques and advanced software analysis, ensuring a highly accurate test result.
  • LED STONE ILLUMINATION & DETECTION: This is a high-performance diamond tester with LED stone illumination and UV fluorescence detection. It uses a unique retractable probe tip that is designed for enhanced durability. The LED stone illumination will help you see the subtle nuances of the diamond, such as clarity, while the UV fluorescence detection allows you to detect any potential diamond treatments. This is the perfect tool for diamond grading, authentication, and identification.
  • POWERED BY USB Type-C: This versatile device comes with multiple power sources. It can be powered by either your USB Type-C cable, rechargeable NiMH batteries, or AAA Alkaline batteries with a battery-saving auto-off function. It includes (3) user-replaceable AAA NiMH rechargeable batteries, a universal multi-voltage 100V–240V AC adapter / charger cube, and a premium USB Type-C cord. You get to choose the power source that works best for you, and the device will be ready when you need it!
  • DESIGNED IN THE USA: The sleek ergonomic shape of the ULTRA TESTER 3+ allows it to comfortably rest in your hand, and its LED stone illumination makes it even easier to see what you're testing! Designed in the USA and recommended by Charles and Colvard. It comes with 2-year limited replacement warranty on probe tip - Lifetime warranty on the electronics. This tester is not intended for Emerald.
  • GEMORO TESTERS: GemOro is a leading manufacturer of gold and platinum testers, as well as diamond, moissanite and white sapphire testers. They are trusted by professionals and hobbyists alike. GemOro's testers are known for their accuracy, reliability, and ease of use.
9.6
Superb
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4
9.4
Superb
Presidium Diamond Mate C (PDMT-C) Diamond Tester | Professional Portable Diamond Authenticity Testing Tool | Diamond and Jewelry Thermal Conductivity Tester with Rechargeable Battery and AC Adapter
Presidium

Presidium Diamond Mate C (PDMT-C) Diamond Tester | Professional Portable Diamond Authenticity Testing Tool | Diamond and Jewelry Thermal Conductivity Tester with Rechargeable Battery and AC Adapter

Why we love it
  • Fast and accurate diamond testing.
  • Portable handheld diamond tester.
  • Rechargeable battery for cordless use.
Main Highlights
  • FAST AND ACCURATE DIAMOND TESTER | Instantly verify real diamonds using advanced thermal conductivity testing technology. Designed to quickly distinguish authentic diamonds from simulants.
  • ESSENTIAL TOOL FOR JEWELERS AND BUYERS | Ideal diamond testing device for jewelry stores, pawn shops, gold buyers, gemologists, appraisers, and diamond resellers who need reliable on-the-spot results.
  • PORTABLE HANDHELD DIAMOND TESTER | Compact, lightweight diamond authenticity tester fits easily on a workbench or in a travel kit for field evaluations, estate sales, and trade shows.
  • RECHARGABLE BATTERY WITH AC ADAPTER | Built-in rechargeable battery allows cordless operation, while the included AC adapter ensures continuous professional use without downtime.
  • EASY TO USE | Simple one-button operation with clear LED indicator system for quick diamond verification. Suitable for both experienced professionals and beginners.
9.4
Superb
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5
9.3
Superb
Save 12%
Presidium Multi Tester III (PMuT III) All-in-One Instrument for Testing Diamonds, Moissanites and Diamond Simulants
Presidium

Presidium Multi Tester III (PMuT III) All-in-One Instrument for Testing Diamonds, Moissanites and Diamond Simulants

12% Off
Why we love it
  • All-in-one testing capability.
  • User-friendly ergonomic design.
  • Highly accurate and portable.
Main Highlights
  • ALL-IN-ONE INSTRUMENT: The world’s first tester that tests for both colorless diamonds and moissanites in a single instrument. Powered by 3 AAA batteries.
  • 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.
9.3
Superb
Save 12%
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6
9.2
Superb
DANOPLUS Diamond & Moissanite Tester Combo - Professional Diamond Detector with Audible & Visual Alarm - High Accuracy & User-Friendly - Ideal for Jewelers, Gemologists & Professionals
DANOPLUS

DANOPLUS Diamond & Moissanite Tester Combo - Professional Diamond Detector with Audible & Visual Alarm - High Accuracy & User-Friendly - Ideal for Jewelers, Gemologists & Professionals

Why we love it
  • High accuracy for precise testing.
  • User-friendly for effortless operation.
  • Portable design for easy transport.
Main Highlights
  • 【High Accuracy】The Diamond&Moissanite Tester is designed to help you quickly determine diamond and moissanite from other fake stones
  • 【User-Friendly】Diamond Detector is easy to operate, hold the meter(by placing your finger on the metal on the back) in 90 Degree position to insert to the surface of diamond, then Green light(diamond) or Blue light(moissanite) will appear on the indicator
  • 【High-precision chip】Diamond Tester is able to detect metal, the inditor will appear orange signal if touch metal material. If without this function, other testers selling on amazon can indicate a real diamond when you unknowingly touch the setting even if the diamond is fake
  • 【Ergonomic Design】Diamond Tester is designed with rubber paint finish, this device provides safe, non-slip comfort and control. It is also equipped with a fine elastic tipped probe for testing and identifying stones with small sizes. When the device stops working due to low battery, please replace the battery or use an adapter (not included) for charging
  • 【Portable & Convenient】It's compact-sized design, it's easy to bring when you need it, where you need it. It also allows continuous use of up to 2 hours and quick probe warm up time of 25 seconds
9.2
Superb
Amazon Logo
7
9.0
Superb
Diamond Tester Professional Diamond Tester Pen with UV Light, 60X Mini LED Magnifying, Jewelry Gem Tester Pen, Professional Diamond for Novice and Expert（Battery Included）
UVER

Diamond Tester Professional Diamond Tester Pen with UV Light, 60X Mini LED Magnifying, Jewelry Gem Tester Pen, Professional Diamond for Novice and Expert（Battery Included）

Why we love it
  • Instantly detects real diamonds.
  • Compact and portable design.
  • User-friendly with clear display.
Main Highlights
  • 💎💎💎Professional Diamond Tester, This diamond tester pen is equipped with high-tech chip, it can effectively distinguish natural diamond in 1 second.
  • 💎💎💎UV Light, The UV light on the diamond tester is used to test the fluorescence color and intensity of diamonds, aiding in the authentication and quality assessment of the diamond.
  • 💎💎💎Operation Procedures, Hold the electricity conductive panel of the diamond meter and ring setting(or metal plate) while testing, the probe of diamond tester should be 90-degree vertical to the diamond.
  • 💎💎💎Portable Diamond Tester Pen and 60X LED Lighted Loupe each comes with its own convenient carrying cases. Both items are small and can fit into any purse or backpack. Diamond Tester Pen and 60X LED Lighted Loupe combo Scal is a must have tool kit when you are going to a garage sale, flea market, swap meet, etc. Alternatively, its also a great tool to have when testing your own jewelry.
  • 💎💎💎Light&Buzzer Alarm, The Diamond Tester has 25 seconds warm-up time after powering on, the red indicator will flash and the buzzer emits regular rings once detecting real diamond.
  • 💎💎💎Easy operation visual indicator, Clear LED display with color-coded testing scale from 1-8 shows precise readings for gemstone authenticity.One-touch testing with automatic power-off feature and ready indicator light for efficient use.
  • 💎💎💎Portable Design, Compact pen-style tester powered by a standard 9V battery (included) for convenient testing anywhere.Suitable for testing various gems and stones including diamonds, moissanite, and other precious stones.One-touch testing with automatic power-off feature and ready indicator light for efficient use.
9.0
Superb
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8
8.8
Excellent
High Accuracy Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor – Fast 0.5s Detection,Diamond Tester, Professional Jewelers' Gemstone Detector (Diamond Tester Pen)
UVER

High Accuracy Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor – Fast 0.5s Detection,Diamond Tester, Professional Jewelers' Gemstone Detector (Diamond Tester Pen)

Why we love it
  • Identifies genuine diamonds quickly.
  • UV confirms moissanite reliably.
  • User friendly for beginners.
Main Highlights
  • Identify genuine diamonds instantly. Accurately distinguish authentic diamonds from simulants like cubic zirconia, glass, crystal, or white sapphire using advanced thermal conductivity. Perfect for screening inherited collections or verifying finds at flea markets and pawn shops, Includes a Standard 9V Battery (same type available in the U.S., easily replaceable) for immediate testing.
  • 365NM UV & MOISSANITE SCREENING : The integrated 365nm UV light reveals fluorescence—an important clue for authenticity. Since Moissanite and fakes show unique color reactions (unlike diamonds), this is a critical second layer of verification. Note: Thermal testing alone may be inconclusive for Moissanite; always use the UV light for a combined assessment.
  • FAST 0.5S INSTANT RESPONSE : After a 25s warm-up, simply touch the stone for a 0.5s response, ensuring a seamless experience for beginners.Using a high-sensitivity thermal probe, hold the conductive panel on the back and touch the stone at a 90° vertical angle. A Red LED and beep instantly signal when a genuine diamond is detected.
  • PRECISION TESTING STANDARDS :For maximum accuracy, follow these guidelines: Use with bare hands (no gloves) to ensure proper conductivity; test at room temperature (50–95°F); and ensure the diamond is 0.02 carats or larger.
  • It is the easiest answer for the vast majority of retail jewelers,pawn brokers and chain stores when faced with the decision of which diamond selector to buy.
  • [Package include]:1 x Diamond Tester Pen, 1 x Tweezers,1 x Testing Platform,1 x 9V battery,1 x a comprehensive instruction manual.
8.8
Excellent
Amazon Logo
9
8.7
Excellent
Purity Testing Kit for Diamonds Gemstones Moissanites Gold Silver and Platinum Jewelry Electronic Digital Diamond Tester Machine JSP GTE
GTE

Purity Testing Kit for Diamonds Gemstones Moissanites Gold Silver and Platinum Jewelry Electronic Digital Diamond Tester Machine JSP GTE

Why we love it
  • Fast and accurate testing.
  • Protects your jewelry.
  • Essential for precious metals.
Main Highlights
  • ALL-IN-ONE GOLD, SILVER, PLATINUM, & DIAMOND JEWELRY TESTING & APPRAISAL KIT
  • FUN, FAST, AND ACCURATE! DETERMINES THE KARAT OF GOLD, SILVER, AND PLATINUM JEWELRY IN SECONDS!
  • AUTHENTIC GTE 3''x6'' JEWELRY TOUCHSTONE FOR SAFE TESTING THAT WON'T DAMAGE YOUR JEWELRY
  • JEWELRY TEST KIT-DIAMOND TESTER-TRIPLET MAGNIFIER
  • A MUST-HAVE FOR ANYONE WHO WANTS TO INVEST IN GOLD, SILVER, PLATINUM, OR DIAMONDS!
  • *BONUS* GTE ACID NEUTRALIZER QUICKLY CLEANS STONE
8.7
Excellent
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10
8.7
Excellent
Save 24%
HMKIS Diamond Tester Pen, Professional Jewelry Diamond Tester with 60X Jewelry Loupe Magnifier, Diamond Selector for Novice and Expert (Non-Rechargeable)
HMKIS

HMKIS Diamond Tester Pen, Professional Jewelry Diamond Tester with 60X Jewelry Loupe Magnifier, Diamond Selector for Novice and Expert (Non-Rechargeable)

24% OffEnds in
Why we love it
  • Powerful precision in testing.
  • User-friendly for everyone.
  • Versatile tool for various needs.
Main Highlights
  • [Power Upgrade] The HMKIS diamond tester offers two power supply options: Type-C and 9V Power (includes a 1m Type-C cable). Utilizing a Type-C power supply delivers a more stable and precise voltage output, thereby enhancing the accuracy and reliability of experimental and test results. Opting for the Type-C power supply is highly recommended for optimal performance. PLZ NOTE THIS IS Non-Rechargeable !
  • [Rapid Assurance] The Professional Diamond Selector II swiftly verifies the authenticity of diamonds with precise accuracy. Designed for quick and secure testing, this diamond selector features an LCD display, LED indicator, and large/small switches for testing diamonds. Audible signals provide further assistance in interpreting readings, ensuring a swift and confident evaluation process.
  • [Easy Use]The HMKIS Diamond Tester Pen is a user-friendly tool that eliminates the need for professional knowledge in diamond testing. With just a few simple steps, anyone can determine the authenticity of a diamond. By turning on the Diamond Tester Pen detector, selecting the diamond size, and placing the tip of the tester on the gemstone, users can easily identify whether the stone is a genuine diamond or if it is made of glass, crystal, or cubic zirconia based on the results. The red light and beep emitted by the diamond tester indicate the presence of a diamond, making it a convenient and easy-to-use tool for anyone in need of quick and accurate diamond testing.
  • [Jewelers Loupe] The 60X LED Jewelers Loupe with batteries is a versatile tool that can be used for a wide range of applications. Whether you are examining gems, coins, antiques, stamps, conducting readings, inspections, jewelry appraisals, studying rocks, watches, calligraphy, paintings, pursuing hobbies, collecting antiques, building models, working in the photo industry, testing electronic products, or simply using it for tasks in your home life or office, this Jewelers Loupe is an essential tool. Its compact design and powerful LED lights make it convenient for use in various settings, providing clear and detailed magnification for all your viewing needs.
  • [Adjust Size]:We have to choose the diamond size before using the diamond tester.Otherwise we may get the incorrect result.
  • [Touch Panel]: We have to touch the panel on the back when testing. Othersize we will get a wrong result.
  • [Incorrect Contact]: When we have incorrect contact, this diamond tester pen will have a flashing OR it will turn off. When you testing metal,skin,or something else.
  • [Warm Notice]:Make sure to test according to the correct testing procedure, avoid using the diamond tester on unsuitable items(metal,skin,water and ect.), to ensure accurate testing results. Any improper operation may affect the accuracy of the test.
  • [Package include]:1 x Diamond Tester Pen, 1X 60XJewelers Loupe,1x 1M USB Cabel,1 x Testing Platform,1 x User Manual
8.7
Excellent
Save 24%
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Related Deals You Might Like for Diamond Tester

📊We scanned 1559 products
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We reviewed the most relevant Diamond Tester offers across Amazon and leading retailers, covering major brands and models. Our shortlist features trusted names like Valkynos, GemOro, Presidium, DANOPLUS, UVER, GTE, HMKIS, known for dependable quality and smart design.
⭐
To determine today's best Diamond Tester, we analyzed 7796 real customer and expert reviews, focusing on satisfaction, real-world performance and long-term reliability. We also weigh each review's relevance, authenticity and freshness for a fair comparison.

Here's what we found:

🏆 #1
Valkynos Diamond Tester Kit with 60X Loupe & UV Light, Thermal Conductivity Diamond Tester Pen for Real Diamonds, Detects CZ, LED & Audible Alert, Tests Small & Mounted Jewelry (2pt / 0.02 ct+)

Our overall winner is Valkynos Diamond Tester Kit with 60X Loupe & UV Light, Thermal Conductivity Diamond Tester Pen for Real Diamonds, Detects CZ, LED & Audible Alert, Tests Small & Mounted Jewelry (2pt / 0.02 ct+) by Valkynos. It stands out for the right balance of quality, performance and value.

✨ What sets it apart:
✓Fast accurate diamond verification
✓Tests small mounted diamonds
✓Portable complete testing kit
💎 Best Value
Valkynos Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor – Fast 0.5s Detection, Portable Gem Checker for Novice & Experts – Battery Included

The best value for most shoppers is Valkynos Professional Diamond Tester Pen with 365nm UV Light & Thermal Sensor – Fast 0.5s Detection, Portable Gem Checker for Novice & Experts – Battery Included by Valkynos, with consistently high satisfaction across expert and customer reviews.

💰 Best Deal
HMKIS Diamond Tester Pen, Professional Jewelry Diamond Tester with 60X Jewelry Loupe Magnifier, Diamond Selector for Novice and Expert (Non-Rechargeable)

The strongest deal right now for Diamond Tester is HMKIS Diamond Tester Pen, Professional Jewelry Diamond Tester with 60X Jewelry Loupe Magnifier, Diamond Selector for Novice and Expert (Non-Rechargeable) at HMKIS, currently at 24% off.

🔄Our Diamond Tester ranking is updated regularly to reflect new releases and price changes—check back for the latest picks and deals.