The 9 Best Diamond Testers
This wiki has been updated 10 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 recommendations, we may earn commissions to help fund the Wiki. Skip to the best diamond tester on Amazon.
August 29, 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.