GOLDANALYTIX GOLDSCREENPEN Bedienungsanleitung Seite 30

 Silver coins with a fineness of less than 958
For silver coins with a fineness of less than 958, the effect of the conductivity drop is particularly
strong. Therefore, it is not possible to verify the silver content with the GoldScreenPen,
especially for typical silver commemorative coins. Rather, it can be ensured that the conductivity
is plausible for silver (>30 MS/m) and the dimensions and weight must be examined very
thoroughly.
 Silver coins special cases
Our tests have shown that the Krugerrand silver coins (.999, 1 ounce) can have values of 55-59
MS/m. The same applies for the "Owl of Athens" and some "Tokelau" coins, amongst others.
 Medals and jewellery
Medals and jewellery cannot be successfully tested by measuring the conductivity. Even if a
piece is completely contiguous, the alloy is not known in detail. At best, one knows the gold
content, but the other unknown components of the alloy have an unpredictable effect on the
conductivity. For jewellery testing, we therefore recommend the Goldanalytix CaratScreenPen,
which can determine the gold content of jewellery alloys.
 5 DM commemorative coins
Particularities of the 5 DM commemorative coins of the years from 1979 (Otto Hahn) to 1986
(Frederick the Great): This series of commemorative coins has a weight of 10.0 g (previous years
11.2 g) and is made of a copper-nickel alloy with a nickel core (previous years silver 625). These
coins show a conductivity of about 2.4 MS/m (Silver 625 at about 47.0 MS/m).
 Alloy impurities e.g. for Vrenelis 20 CHF
The range of possible impurities and their consequences are impossible to be comprehended
entirely. However, in our tests we found that Vrenelis 20 CHF, for example, sometimes had 10 to
20 times the iron content of cleanly produced Vrenelis of the same year. The gold content was
correct in all of those coins (90% gold content), but in some coins, XRF-analysis detected a much
higher iron content, in addition to copper, suggesting improper minting. Since the
GoldScreenPen is a very precise eddy current measuring device, such impurities are detected
and lead to lower conductivity values for the measured coins. Such coins are not to be
considered as counterfeits, but merely as unclean variations of real coins, which often have a
ferromagnetic contamination (iron or nickel). It is therefore essential to combine more testing
methods for such coins (e.g. density testing or XRF-analysis) in order to distinguish whether the
coin is indeed a fake of just one of the cases described above.
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