Important Hints For Measuring With The Goldscreenbox - Goldanalytix GoldScreenBox Instruction Manual

9. Important Hints for Measuring with the GoldScreenBox

We recommend dropping all your mobile devices (i.e. smartphone, mobile phone or flash drive
with wireless access) at least 1 m far away from the testing device due to the inductive eddy
current principle of the device. The relatively high radiation density which is especially high during
connection setup can lead to false measurements. The latter can be recognized by strong
deviations or oscillations of the value. After restarting the device can be used without further
restrictions. Wireless LAN / Wifi or Bluetooth do not influence the measurement.
When using the regular measuring mode the objects should cover the measuring circle
completely. Our measurements have shown that coins of the size of the Vreneli and also ¼ ounce
coins still work very well. For 1/10 ounce coins and 1, 2/2.5 and 5 gram bars you should use the
measuring modes on page 2 of the precious metal selection (see "Special case small coins and
bars").
Old coins / bars ("old" defined as before World
th
War II) and especially objects of the 19 century
may partly differ in their composition. That
means that the gold content is right but the
composition of the remaining amount of some
coins deviates. In terms of .900 gold, those coins
should consist of 900 parts gold and 100 parts
copper. However, due to non-optimized
production processes and analysis conditions
those coins are contaminated with foreign metals
which change the conductivity. Moreover, the
gold used for procuding these coins has not been
100% pure so that further impurities got into the molten metal and finally into the alloy. For
instance, gold was obtained by various raids and expeditions during those times (at ca. 1800 and
later on). Therefore, please be aware: We only can offer set values of correctly produced coins
(mainly precious metal-copper alloys, sometimes nickel).
The range of possible impurities and their consequences can not be comprehended entirely. With
our testing experience we found, that some Vrenelis 20 CHF sometimes have 10 to 20 times
higher iron content than their cleanly produced "colleagues" of the same year. The gold content
was correct in all of those coins (90%), however besides copper and silver some coins showed
significantly higher iron contents in XRF-analysis. This means that Vreneli coins from 1922
sometimes were minted inaccurately and that not all components were controlled properly.
Through its highly accurate measuring system the GoldScreenBox recognizes those impurities,
which leads to lower conductivity values for the measured coins (iron lowers the conductance).
Old coins that fall into this category are not to be considered as fake but rather as variations of the
coin. In this case we highly recommend combining more methods like a density test, gold testing
acids or a XRF-test, to gain more data and find out if the coin contains the right amount of gold (or
less, which happens quite often, too) or if its just an impurity, that changes the conductance.
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