Duo Tester II (PDT II)


Introducing Presidium’s Assisted Thermal Calibration (ATC) function using newly redesigned in-built calibration discs to ensure accurate and consistent tests for both indoors and outdoors operation.

Presidium Duo Tester II (PDT II) is the only comprehensive tool on the market that combines two proven testing methods for gemstones. PDT II differentiates diamonds from its simulants based on both their thermal conductivity and reflective indexes. Coated gemstones can also be generally tested with the PDT II.

The Presidium Duo Tester II comes with a probe pen that has a retractable probe tip which ensures consistent pressure against the gemstone during testing for more reliable results. With the industry’s thinnest probe tip size of 0.6mm, PDT II tests gemstones as small as 0.02ct.

*Does not differentiate between natural and synthetic colored gemstones.


• Assisted Thermal Calibration (ATC)
• Built-in Glass and Calibration (CAL) test discs for reference
• Retractable thermoelectric probe tip that ensures constant pressure between probe and gemstone
• Industry’s thinnest probe tip (0.6mm) for testing gemstones as small as 0.02ct
• Metal alert buzzer to ensure that probe tip is in contact with gemstone during testing
• Large easy-to-read analog dial with 16 colored gemstones
• Digital index LED display for reading of reflectivity value of the gemstone (based on conversion from refractive index)
• Built-in simulant reflective properties reference chart
• Diamond simulant set for calibration of reflectivity meter (optional item provided by Presidium)


• Tests gemstones using dual tests of thermal and reflectivity properties to know more about the gemstone
• Accurate and consistent tests for both indoors and outdoors operation
• Tests gemstones as small as 0.02ct
• Clear and visible display for ease of reading measurements for both thermal and reflective test
• No waiting time between tests
• Simple and easy to use
• Runs on 5 AA batteries or with recommended Presidium AC adaptor


Power & Battery

5 x AA alkaline batteries (approximately 3 hours of continuous use)

AC port to be used with appropriate Presidium Power Adaptor (not included)


Recommended Operating Conditions

Optimal Operating Temperature: 18°C – 27°C (65°F – 80°F)

Storage Temperature: 10°C – 51°C (50°F – 124°F)

Dimensions & Weight

Length: 172mm (6.77 inches)

Width: 77mm (3.03 inches)

Height: 85mm (3.34 inches

Weight (without batteries): 260grams (9.17 oz)

Additional information



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