Order-No. 8318GI


Gem Indicator

The Presidium Gem Indicator, the only handheld tester in the industry specifically for colored gemstones, indicates up to 31 different types of colored gems based on their thermal conductivity and even features a color input function that allows users to select from a range of 12 common colors, thereby achieving more accurate results. With an easy-to-read clear digital LED screen, this smart thermal tester also comes with the Presidium patented refined changeable probe tip, which ensures minimal equipment downtime.

How to Perform a Test Using the Presidium Gem Indicator (PGI)How to Perform a Test Using the Presidium Gem Indicator (PGI)

  • The Presidium Gem Indicator is an enhanced and more convenient handheld version of the revolutionary Presidium Gem Tester/Colored Stone Estimator.
  • The Presidium Gem Indicator probe consists of two linked thermometers; one which is heated electronically, while the other is cooled by the gemstone being tested. The difference in temperature creates an electrical output, which is then amplified and displayed on the new digital organic LED display.
  • It is simple to use, easy to maintain and quick in giving you intelligent results about your colored gemstones.


  • Tests an extended range of 31 different gemstones
  • Color input function to further separate gemstones for more accuracy
  • Easy-to-read results on clear digital LED screen
  • Quick results in less than 6 seconds
  • Industry’s thinnest probe tip (0.45mm) for testing gemstones from 0.02ct
  • Patented refined probe tip
  • Metal buzzer alert and low battery indicator
  • Sleek chrome-brushed ergonomic grip
  • USB port for alternative power source and connectivity


  • Also able to distinguish diamonds from other colored gemstones
  • Selection of 12 common colors available for more accurate results
  • Retractable thermoelectric probe tip that ensures constant pressure between probe and gemstone, for enhanced accuracy
  • Slim, light, portable and handheld for convenience


  • Power & Battery
    3 x AAA alkaline batteries (approximately 3 hours of continuous use)
  • USB port to be used with USB cable and appropriate Presidium Universal USB Power Adaptor
  • Recommended Operating Conditions
    Optimal Operating Temperature: 23°C – 27°C (73°F – 80°F)
    Advised to run the calibration process if you are operating in ambient temperatures of  20°C – 33°C (68°F-91°F)
  • Dimension & Weight
    Length: 170mm (6.69 inches) / Width: 31mm (1.20 inches) /Height:28mm (1.10 inches)
    Weight (without batteries): 60.0grams (2.11 oz)

Presidium Gem Indicator (PGI) Performing a Test and Reading ResultsPresidium Gem Indicator (PGI) Performing a Test and Reading Results

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