Question About Metal Origin.

In a word, yes.

I picked up a fascinating book some time ago from a coin club auction: "Metallurgy in Numismatics, Vol. 1", put out by the Royal Numismatic Society in 1980. It's got a series of articles on chemical and metallurgical analysis of coins ranging from ancient Greek and Roman through to Byzantine, Islamic and mediaeval English hammered.

Well, I'm into chemistry, so it's fascinating to me, anyway.

For instance, they've been able to use lead isotope ratios and trace impurity analysis to match ancient Greek silver coins like Aeginian "turtles" to old silver mines on the nearby island of Siphnos, and to mines at Laurion on nearby mainland Greece. Corinthian "colts" from the same hoard, on the other hand, are almost exclusively made from Laurion silver.

Of course, the big problem with coins is that once mined and minted, coins could wind up anywhere, mixed together with coins of different times and places, where they'd all be melted down to make new coins.