Frequently Asked Questions | Goldanalytix
Here you find answers to the most frequently asked questions on all topics related to precious metal testing. The questions and answers are neatly arranged according to key topics - so you can find what you are looking for very quickly.
For some new fine gold investment coins (e.g. Kangaroo 2021, Lunnar Series III 2021) the measurements are at the upper end of the spectrum (mostly 46 to 48.5 MS/m). Thus, some coins are shown in the yellow zone, even though they are real. This is probably due to a new type of coating on the coins, which is supposed to protect them from damage. Therefore, if the dimensions and weight are correct, there is no need to worry.
The GoldScreenBox and the GoldScreenPen measure the conductivity of your precious metal object using eddy current testing. The coil of the respective device induces a magnetic field that creates eddy currents in the object. This allows the conductivity to be determined, which the tester outputs in megasiemens per metre.
Each precious metal has a specific conductivity, therefore contamination would be immediately noticeable in a measurement. If a precious metal is underalloyed or has a core of foreign metal, our devices show you this with a target/actual value comparison. The GoldScreenBox additionally gives you the result in the form of a coloured illustration of green, yellow and red.
In some silver coins (fineness 999) there are "impurities" in the last thousandth in the sense of e.g. iron or nickel, which can be traced back to unclean production methods in the past. The classic coin for this is the Krugerrand silver (conductivity: approx. 55 - 60 MS/m). This means that the coin often slips into the yellow or even red range on the GoldScreenBox, although it is real.
Additional measuring methods will confirm the authenticity of the coin.
The same effect can also be seen with other objects such as the silver coin "Tokelau 4th Edition Terra | Earth 2021".
When measuring, it is important not to measure only at one point, but to always take measurements at several points on the object for the test. In addition, you should take care not to press on the tip of the GoldScreenPen, but only to place it on the object. Otherwise, the GoldScreenPen may measure its own metal tip. In order to obtain an accurate measurement result, the measuring tip must be in full contact with the test specimen and not only in partial contact, otherwise the device will measure air and this can distort the measurement result. With extremely small or small-limbed pieces, no clear result can be delivered.
In addition, it is important to pay attention to the size/thickness of the object, because if the test piece is too large, the GoldScreenPen can no longer identify all forgeries, as the penetration depth could be too shallow. Therefore, please use the GoldScreenPen only for bars and coins up to 1 ounce. In addition, at least one other measuring method should be used (e.g. calipers and precision scales).
In fact, the nominal value of 9999 silver with approx. 62 MS/m is slightly higher than that of 999 silver with 60.5 MS/m. Of course, when measured in practice, the values deviate slightly from the nominal value due to temperature, minting and packaging.
Coins with the fineness 9999 can therefore be in the higher green and sometimes also in the yellow zone.
Silver coins with "only" 999 of 1000 parts of silver are now and then in the lower green or even in the adjacent yellow zone (displayed on the GoldScreenBox).
Caution: In the case of a counterfeit, you are not only threatened with high financial losses, because if you knowingly or even unknowingly resell the counterfeit gold, you also make yourself liable to prosecution!
No. The GoldScreenPen measures the conductivity (like the GoldScreenBox) and is therefore ideal for counterfeit detection. Sub-alloys or the exact carat number cannot be measured with a carat number smaller than 21, because the conductance values of these alloys only decrease very slightly with decreasing gold content.
Currently, the test acids or the density scale are the best methods to determine the carat number.
A device that fulfills exactly this function is currently under development and is expected around the end of 2021.