GoldScreenSensor

The GoldScreenSensor and the GoldScreenPen measure the conductivity of your precious metal object using eddy current testing. In this process, the coil of the respective device induces a magnetic field that generates eddy currents within the object. This allows the conductivity to be determined, which the testing device displays in megasiemens per meter. Each precious metal has a specific conductivity, which is why any impurity would be immediately detected during a measurement. If a precious metal is alloyed with another metal or has a core made of a foreign metal, our devices will indicate this by comparing the target value with the actual value.

The GoldScreenSensor or the GoldScreenPen are worthwhile investments if you enjoy buying coins and bars from private individuals or want to reliably verify your inventory. Thanks to the devices’ unique functionality, you can protect yourself from fraudsters. Even with limited technical knowledge, our devices are easy to use and the results are simple to interpret. Warning: If you encounter a counterfeit, you not only risk significant financial losses—if you resell the counterfeit gold, whether knowingly or unknowingly, you may also be subject to criminal prosecution!

It is important to pay attention to the size/thickness of the test piece, because if it is too large, the GoldScreenSensor cannot penetrate deeply enough and the measurement may be inaccurate.

Therefore, please use the GoldScreenSensor only for bars and coins weighing up to approximately 2 ounces. In addition, you should use at least one other measurement method (e.g., a caliper  and a precision scale).

In general, you can test all bars and coins with the GoldScreenSensor. However, there are cases that limit the accuracy of the measurement.

For thicker test objects (50 to 100 grams or more, depending on the geometry), we recommend using the BarScreenSensor  in addition to the GoldScreenSensor to account for thickly rolled gold plating.

Coins smaller than 1/4 ounce have a slightly different conductivity value than the material should have, since the measurement area is not fully covered.

Old coins (pre-1945) may also sometimes contain impurities. For example, 986 ducats consist of only 986/1000 parts gold; ideally, the rest is copper. However, since the refining process had not yet been sufficiently perfected at that time, these 14/1000 parts may also consist of other metals that distort the conductivity value.

Furthermore, the GoldScreenSensor cannot penetrate particularly thick blisters and capsules (>3 mm), such as NGC packaging.

For some new fine gold bullion coins (e.g., 2021 Kangaroo, 2021 Lunar Series III), the measured values are at the upper end of the spectrum (usually 46 to 48.5 MS/m). As a result, the conductivity of some coins is displayed as too high on the GoldScreenSensor, even though they are genuine. This is likely due to a new type of ultra-thin coating on the coins, which is intended to protect them from damage. Therefore, as long as the dimensions and weight are correct, there is no cause for concern.

In some silver coins (999 fineness), the last thousandth contains “impurities” such as iron or nickel. A classic example of this is the Krugerrand silver coin (conductivity value: approx. 55–60 MS/m). As a result, the coin’s conductivity value on the GoldScreenSensor often falls into the lower range, even though it is genuine. Additional testing methods will confirm the coin’s authenticity. The same effect can also be observed with other items, such as the “Tokelau 4th Edition Terra | Earth 2021” silver coin.

In fact, the target value for 9999 silver—at approximately 62 MS/m—is slightly higher than that for 999 silver, which is 60.5 MS/m. Of course, in practical measurements, the values may deviate slightly from the target value due to variations in temperature, minting, and packaging. The conductivity values of coins with a fineness of 9999 can therefore fall within the higher range and sometimes also within the lower range. The conductivity value of silver coins containing “only” 999 parts silver out of 1,000 occasionally falls within the lower range or even the adjacent lower range.

1. Compare the dimensions with the manufacturer’s specified dimensions.

2. Check that the weight is correct.

3. Measure the conductivity using eddy current measurement. For the final step, we recommend the GoldScreenSensor for investment metals ranging from 1/4 ounce to approximately 2 ounces (depending on geometry and material).

For more information (including details on various sizes and shapes of precious metals), please visit the Goldtest page.

The battery lasts over 10 hours with active use. Charging takes about 2 hours. If you would like to have your device's battery replaced, please feel free to contact us, and we'll take care of it for you.