Russ Bega wrote an article about a coin that crossed our paths at Harlan Berk. Years ago, it crossed @Insider desk as well. If you'd like to read it: article - Counterfeit, He Wrote
Having been one of the experts to examine the coin I can tell you this: it was a REALLY good fake and I don’t think anyone knew for certain until we had the coin analyzed via xrf. The composition wasn’t correct, even though it weighed almost exactly what it should have, but the Mint would never put platinum in a silver quarter planchet. That was the moment we knew, and I’m pretty sure we were the first to know for sure.
Do you mean palladium, not platinum, that was around the 3/4% mark? That is what the story said. But still would never be that high. I don't know how reliably XRF gets the bulk composition, but shouldn't genuine coins be very near 90.0% silver 10.0% copper? That composition seals the deal as a counterfeit.
Interesting story. Thanks for posting. The U.S. Mint (government, secret service) aren't experts? They said the coins were legit. Either palladium or platinum doesn't matter...neither belong in a 1934 quarter planchet. The real question is how did the U.S. Mint miss this...the Mint is quoted as saying the coins were legit??? The answer to this question was not addressed in the article (sorry if I missed it).
I said "TPGs/experts" because as far as I know, some of the ones they submitted to (ANA, INS, Coin World) aren't technically TPGs, just "experts". The part where "laboratory analysis by the U.S. Secret Service" deemed them genuine is pretty damning. I'm curious if there's something normally made with silver, copper and palladium that the counterfeiter could have melted down to make the planchets. It seems like an odd alloy to use.
I've followed the story of these for some time. In my opinion they are genuine, not "counterfeit". The XRF test is likely inaccurate, and the testing device margin of error was probably greater than the percentage of Pd/Pt reported.
I can tell you for fact that the likelihood of the xrf being wrong is very small. It was a major refiner here in Chicago that did the analysis for us.
If someone has one of these supposed "counterfeits", it would be worthwhile to make another close examination of it.