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The most handy and accurate diamond tester pen for sale

As a key, flagship product from Gemlogis, the LAPIS ONE diamond tester pen provides ease of use, accuracy and rechargeability when distinguishing between diamonds, moissanites and simulants.


The handheld design of the LAPIS diamond testing pen is light and yet user-oriented, and it comes with the compact features that provide quick results without any delay. LAPIS is the all-in-one and the best diamond tester pen that makes sure you don’t ever mix up natural diamonds with other stimulants. With its competitive diamond testing pen price, it is simply the most convenient and value-for-money choice on the market today!

4 key features of LAPIS ONE diamond testing pen

1. Simple and easy to operate:

Charged and removed the oxidation before use. Then simply press the probe tip of the diamond testing pen against the gemstone, and it will do the rest by promptly delivering the accurate and reliable results.  (Check out the video below for more detailed usage instructions)​

2. Retractable tip designed at ergonomic testing angle:

The ergonomic design of the LAPIS diamond tester pen allows you to perform tests in a comfortable way. Its retractable tip design makes sure that consistent pressure can be applied against the gemstones while using it.

3. ATC Solution accounts for different temperature in environment:

The LAPIS is the best diamond tester pen which has an inbuilt thermos sensor that performs ATC (Automatic Temperature Compensation) solution to adapt to ambient temperature for enhanced accuracy, making it one of the more unique diamond tester pens for sale on the market.

4. Rechargeable battery:

The LAPIS diamond tester pen is powered by lithium rechargeable battery. A fully charged battery should work continuously for 10 hours. It saves you time and costs, which makes LAPIS’s overall diamond testing pen price truly very competitive.    

best diamond tester pen results

What qualifies the LAPIS as the best diamond tester pen? In addition to its light weight and compact features, the LAPIS diamond testing pen requires a simple test procedure only, and the results are indicated by different colored LEDs in the Results Window. It’s just simple and clear!

What’s more, the distinctive sound feature of the LAPIS diamond tester pen makes it possible to di­fferentiate metal, diamond and moissanite with different beep patterns, even without looking at the Results Window.  

Green LED

Yellow LED


Blue LED

When the green LED lights up with a continuous beep, it means it is a diamond.

When yellow LED lights up, accompanied by a slow and intermittent beep, a moissanite is identified.

If the red LED lights up, the gemstone you tested is a simulant.

If metal is detected, the blue LED will light up together with a fast intermittent beep.

Technical specs of diamond tester pen

  • Effective Testing Range: 0.02ct or above

  • Color Range: Colorless (D-J)

  • Dimensions (mm): 171 x 29 x 20

  • Weight (g): 70g

  • Battery Capacity (hours): 3hrs non-stop. 720hrs standby.

  • Factory Warranty: 12 months

User Manual

See our FAQ for product Troubleshooting

More about LAPIS ONE diamond testing pen – FAQs:

  • Why I am getting inconsistent results?
    Gemlogis testers require a certain level of user experience to handle properly: Make sure to clean the probe tip and remove oxidation Make sure to clean the surface of the gemstone to remove any grease and dirt Make sure the gemstones are at room temperature (remove from body/pocket to let it cool down) Make sure to point the probe tip at a perpendicular angle against a flat surface of the gemstone Make sure to allow the gemstone to cool down between consecutive tests Make sure to test different spots on the surface of the stones, due to the impurities on the stones, it may affect the results.
  • Why does moissanite indicate as diamond on some occasions?
    In some instances there may be a disproportional allocation of silicon carbide located on a moissanite; therefore, performing several tests on different spots (including the girdle) of the gemstone is recommended.
  • Can Gemlogis thermal testers detect uncut raw/uncut stone?
    Yes, as long as the stone has a clean & flat surface.
  • Will the size of the gemstone affect the test result?
    Yes. Smaller stones conduct less heat from the probe tip. Hence, the reading indicated may be slightly lower.
  • Why do blue diamond & black diamond indicate as moissanite or metal?
    Blue Diamond is a semiconductor due to the substitution of boron impurities in place of carbon atoms. Black Diamond is substituted with graphite or iron inclusions. Both blue and black diamond will indicate as moissanite or metal on the tester.
  • Why do I sometimes hear intermittent beeping when testing gemstones?
    Whenever the probe tip touches a metal surface, an intermittent beep will sound. This is only applicable to mounted gemstones.
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