How to Read a Diamond Tester

While diamonds are quite possibly the most valuable stone in the world, their cut and clarity varies, and a wide array of fakes and counterfeit diamonds are available in the market. In order to determine whether a diamond is real or not, however, you can take the help of a diamond tester.

Diamond testers are useful electronic tools, used to test the authenticity and purity of diamonds. These convert the thermal conductivity of a stone into readable data, and give a positive or negative reading, depending on whether the diamond is real or not. Diamonds and ordinary gemstones can be distinguished by one factor – thermal conductivity. This tends to be high for diamonds, and low for regular gemstones.

Things Required:

– Diamond Reader
– Test stone(s)
– Diamond


  • 1

    Start by reading the instruction manual that comes with your diamond tester. While the general method for using these devices is that same, small details may vary from model to model, so make sure you read all the instructions provided carefully, and get a good idea about the settings, battery power, and output method of your particular diamond tester.

  • 2

    Before you turn it on, make sure the tester is equipped with new, fully charged batteries. The fine-tipped probe will be covered with protective material – take this off, and adjust the settings of the tester, as per the instructions in the manual. Now, proceed to turn the tester on, and wait for it to warm up.

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  • 3

    Now, in order to test whether the device is working correctly or not, try it out on a stone you already know the configuration of. For example, you can use a stone you already know is a diamond, or try it out on a purple gemstone, that is bound to produce a negative result.

  • 4

    To test it, connect the probe with your stone, and wait for a reading – most testers will only require you to touch the probe to the stone for a few seconds at most. Once the reading comes up, check to see if it is accurate. If your test stone is not a diamond, and the reading that comes up is negative, you will know your tester is working correctly.

  • 5

    Once you have ensured that it is working fine, the diamond tester is ready for use. Connect the probe to your diamond, and find out whether it is real or not.

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