Presidium Duotester Manual - iGem Instruments
Thermal Conductivity Measurement
Makes use of the fact that diamond conducts heat better than any known diamond simulant.
- insert five size A A Alkaline batteries or connect the instrument via the adapter (1) to a mains outlet,
- link heat per (2) to meter by inserting the multi-pin plug at the end of the cable into its socket.
- turn on the switch (3) and wait about 20 seconds.
Red indicator lamp (4) glows.
- press the tip of the pen (Fig. A) on the metal disc (5) "TEST DIAMOND " until the tip is fully retracted into the pen.
The needle goes well into the green zone.
- press the tip of the pen (Fig. B) on the synthetic sapphire disc (6) "TEST SIMULANT ".
The needle stays in the red zone. The optimal needle position is more or less perpendicular to the base of the meter (see "Calibration ").
Calibration
Select a stone from the Substitute Set (push tray out from opposite side)(13).Turn the recessed screw (14) "Cal 211 with a screwdriver until the displayed number is well within the range of its Reflectivity Number on the chart.
Important Notes
Thermal Conductivity Measurement
- The gemstone should appear to be dry and reasonably clean before testing.
- Rather low readings in the green zone must be expected with very small diamonds.
Reflectivity Measurement
- The gemstone should have a good polish and be perfectly clean before testing. The pad should be free of dust.
- Synthetic Spinel/Synthetic Sapphire and High Zircon/G.G.G. have overlapping Reflectivity Numbers. If in any doubt, use thermal conductivity measurement for easy separation. Synthetic Sapphire: needle goes to a high position in the red zone.
Synthetic Spinel: needle goes about halfway into the red zone.
High Zircon: needle goes 2/3 into the red zone, G.G.G.: needle goes 1/3 into the red zone.
General
When a number of tests are being made, it is advisable now and then to check calibration to ensure correct results. The PRESIDIUM DUOTESTER has been subjected to thorough factory quality control. It will give a conclusive and reliable answer to the question whether or not a particular gemstone is a diamond.
Under no circumstances shall PRESIDIUM INSTRUMENTS Pte. Ltd., the manufacturer, or any of its distributors be liable for Direct or indirect Damages Sustained in Connection with the PRESIDIUM DUOTESTER.
Maintenance
Thermal Conductivity Measurement
- The heat pen and particularly its tip should be handled carefully. When the heat pen is not in use, always replace the protective cap.
Reflectivity Measurement
- Keep the test pad free of dust. Always replace the protective cover after use.
- When mounted stones are not recessed in their setting, their reflectivity can be measured. Use a black plastic box (e.g. photographic film container) as an alternative to the recessed cylinder.
