Discovered pirate coins might solve mystery...Arrgh!

[Rick]

I expect that this post is just a rehash of Fernando's above.
From a bit of research I have found that nondescript foriegn coins in that age that were made from gold or silver were valued by weight. I expect innkeepers and tavern owners kept a small balance scale and weights. If one knew (for example) the value of a Thaler then the equivalent weight in silver could be adjudged as the same.
Purity and counterfeit might be a problem; I always think of the image of a merchant biting a coin to asses its purity.

[fernando]

It was not easy to circumvent counterfeight. Weighing was a practical method, but fakes could be made with metals of similar density and bathed in gold or silver; nowadays with electrolysis.
Biting the coin is another story, as we start by stripping the act from some fiction. In the old days, integrity of pure gold coins was of concern, as it was soft enough to wear with time and also subject to shaving (edge clipping)*, in both cases losing intrinsic weight. Circa 1526 a blend with a harder metal was invented to give gold some toughness.This way when (if) the recipient bit the coin to check on its authencity based on the gold malleability, the test was inconclusive due to its resistence.
Also not to forget that, due to its unique characteristics, there are those who pretetend that 'tasting' the flavour of gold is a good test.
* A system implemented to prevent this was the minting of coins with an edge (rim) to allow for the eye checking of this highly punishable crime; but that is another story.


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