Presidium Gem Tester PGT II, for coloured gemstones and diamonds

The Presidium Gem Tester II provides a quick, simple and laboratory-proven method for identifying and distinguishing a total of 15 different types of gemstones.

The lightweight, portable unit is powered by the included 110-220 V power supply or by 2 x 1.5 V AA batteries (not included). A protective carrying case is included.

Function

The advanced thermoelectric probe is placed on the surface of any stone, mounted or loose, and the specially calibrated scale indicates the relative thermal conductivity of the stone. For the purpose of the test, it is irrelevant whether the stone is polished or not.

The exact function of the PGT II is based on the fact that different gemstones conduct heat at different rates.

Calibration

Calibration is mostly automated and only takes a few minutes. It is facilitated by the two test discs mounted on the frame. Manual adjustment of the potentiometer is not necessary.

Test procedure

After switching on, there is a warm-up phase of 20 seconds. No further warm-up time is required between tests. PGT II has a built-in metal detector that warns the user if the setting is accidentally touched instead of the stone. The duration of the test is about 2 seconds.

The test probe is retractable, thus ensuring constant pressure between the probe and the gemstone. It is only 0.6 mm thick and allows testing of precious stones from 0.02 ct.