Or maybe we should ask ourselves if such “tests” are in any way conclusive.... https://auctions.stacksbowers.com/lots/view/3-2ERAP
I highly doubt that OP has a 6 figure value coin. All of the 1943 copper cents were probably accounted for after 75 years.
NGC just certified another 1943 copper cent earlier this year. http://www.coinnews.net/2019/02/25/ngc-certifies-rare-1943-copper-cent-found-in-gumball-machine/
Not sure to be honest. It was all dated 1960 and earlier though. The oldest coin I found in it was a 1915.
Interesting. The gumball coin was originally found in 1976. If the most recent coins were from the 1960’s, then this 1943 copper cent would pre-date all the modern Alibaba counterfeits. I believe the pedigree of a coin like this is just as important as any diagnostic tests in determining its authenticity. If it can be proven that this coin has been kept in a coin jar for the past ~60 years, then that increases its odds of being a genuine 1943 copper cent.
At least 2. Two previously unknown, to the numismatic community, coins appeared on the market in 2017. They were in the estate of a former mint employee who was working in the mint in 1943.
While they may have come on the market in 2017, those coins (the mint worker) were found in 1943. And rare coins in the possession of a mint worker, seems highly suspicious and illegal to me.
You did note I said they were unknown to the numismatic community. Sure the ex-mint worker know about them but no one else. And yes the fact he had them, TWO of them, is very suspicious.