Updated September 11, 2019 by Kevin Flores

The 9 Best Diamond Testers

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Best High-End
Best Mid-Range
Best Inexpensive

This wiki has been updated 8 times since it was first published in April of 2018. Diamonds have been prized for thousands of years, and it's likely that fakes of these valuable forms of carbon have been around since their discovery. Luckily, prospective buyers can rely on more than just their eyes to weed out the frauds from the real deals. We've sorted through a wealth of cheap, knockoff electronic testers to bring you some of the most reliable detectors. When users buy our independently chosen editorial picks, we may earn commissions to help fund the Wiki. Skip to the best diamond tester on Amazon.

9. GemOro UltraTester 3+

8. Presidium Gem Tester II

7. HDE High Accuracy

6. Gemoro Testerossa

5. Gemetrix Melee Inspector

4. Presidium Diamond Mate-C

3. Oris Terminator II

2. Gemlogis Mantis 3 in 1

1. Presidium Adamas

Editor's Notes

August 28, 2019:

In ranking these diamond testers, we paid close attention to the method they used to identify fakes. Most devices on the market test for phosphorescence, hardness, and electrical and thermal conductivity. Knowing the strengths and limitations of each of these methods will help you make a better decision when it comes time to purchase a tester.

Synthetic moissanites, which are popular diamond alternatives, can often fool diamond cheaper testers, especially those that solely measure thermal conductivity, such as the Presidium Diamond Mate-C, since heat moves through both types of stones at about the same rate.

Moissanites also have a similar hardness than diamonds, so the HDE High Accuracy is better left for situations where you're trying to differentiate between natural gemstones instead of trying to detect lab-made ones.

Because they use a combination of testing methods, our top two choices, the Presidium Adamas and Gemlogis Mantis 3 in 1 are able to reliably test for synthetic gemstones, though they are pricier than many of their competitors.


Kevin Flores
Last updated on September 11, 2019 by Kevin Flores

Kevin Flores is an award-winning journalist and documentary filmmaker whose work has been featured in several major media outlets. Word thrift and clarity were pounded into his prose by merciless editors during his days as a breaking news reporter for a wire service. These days he can usually be found trawling through public records and tracking down shadowy shell companies for a nonprofit media organization he co-founded. He enjoys his time away from the screen by pursuing a hobby restoring furniture, giving him special insight into woodworking tools and materials. His filmmaking experience also turned him—willing or not—into something of an audio and video equipment fiend.


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