Any One Good A Chemistry

In any scientific test, it's always good to have a "control". If you've got two coins you wish to investigate, then submit a third coin for analysis, one that seems perfectly normal and has no issues or problems whatsoever. That way, you can tell the difference between things that are actually strange about the sample and things that have gone wrong with the testing.

I have two quick questions about the test.

First, what was the test, exactly? XRF? You still seem to have the coins with you, so it's safe to assume it wasn't an ICP test like we use in the lab where I work - for that test, you need to dissolve the entire coin in acid first. The nature of the test will also affect the interpretation; XRF is surface analysis only, and doesn't tell us whether the coin is solid coppery metal or whether it's simply picked up a coppery coating from someplace.

Second, as others have asked, what are the units? It's impossible to interpret results that are just a bunch of numbers, without knowing what the numbers represent.

the other ten cent piece with no reading on edge micro views of the rim with a another 10c beside it

cost nothing had 5 items done took about a hour sorry cost me a bottle of vodka will let you know the other items when I have done some more home work

Only 0.065%

Its possible (pretty likely) the silver was picked up by the coin rather than having been there in the original planchet.

The second coin with no rim is coated with mercury, Hg. I wouldn't touch it with bare hands.

OK, I've figured it out now - they've used one of these, a handheld XRF analyser. I work in a lab at UQ St Lucia; I didn't know somebody local had access to one of these.

Which does answer my previous question: XRF is a surface analytical technique; it won't tell you if the result is just surface contamination, or if the composition is like that all the way through.

That being said, there does not appear to be a lack of nickel in your "coppery" coin; the opposite, actually, with a Cu:Ni ratio of 2.8:1 rather than 3:1, there is a slight reduction in copper content; this would not account for the copper colour. I'd still conclude it was environmental damage. For a relatively pure metal, adding up all the ppm figures "should" give you pretty close to the theoretical 1 million parts per million; this coin falls far short, meaning there's an awful lot of undetectable elements (oxygen, carbon, nitrogen, chlorine, etc) sitting on the surface.

The "rimless" coin has the same problem, only worse: a distinct overabundance of nickel, with a ratio of 1.5:1, twice what it should be. What it doesn't really tell you is why: is there twice as much nickel as there should be, or is half of the copper missing? Copper being stripped from the surface selectively is far more probable than vice-versa, as copper is more electropositive than nickel. But I don't know if such "surface enrichment" is normal for well-circulated cupronickel alloy coins.

Here is where a couple of controls might have come in handy: a bright, mint-fresh coin, and a well-worn but otherwise normal coin.

As for the trace levels of other stuff (manganese, silver, mercury, etc), that's pretty much par for the course with raw metals that are sourced as cheaply as possible. It's too expensive to remove those last few fractions-of-a-percent of contaminants, if you don't really need to do so. It doesn't really mean too much, except that such trace-level detection can in theory be used to "fingerprint" the metal and trace it back to its origin. I've read about analytical work done on ancient coins that demonstrate the likelihood that certain ancient coins were likely to have had their metal mined from a certain place, as opposed to another place.