That's basically what I was referring to... On at least the two that I've seen, SEMs have the ability to perform some form of spectrometry to analyze the elemental composition of the surface of an object. There's no point in getting a high-res image of the thing... that won't tell you anything. But an element-by-element analysis of the surface will tell you whether or not any gold is present.
I'm sure there are other means of achieving the same thing, but the point is, there are ways of doing it.
A few years ago, I had a loonie I suspected to be fake. I brought it to the science department at the local university and found someone who had an SEM. We put the loonie under the scope, did an analysis of it, and determined that it was made of all the right elements in roughly the right ratios, so it was more than likely authentic. We even made a gouge in the surface to expose the metal at the core and found the same results. I don't recall the exact name of the method of analysis we used, but I believe it was a form of spectrometry.
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BWJM, F.O.N.A.
Life Member of CPMS, RCNA, ONA, ANA, IBNS, WCS.
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Treasurer, Waterloo Coin Society.
Show Chair, Cambridge Coin Show.
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