Any ideas how to determine whether a coin is copper or brass?...

[Iron Patch]

Without hurting it.

I have a token that is only known to exist in copper, but I have one that sounds and registers well below what it should and I'm thinking it could be brass.

For any Explorer users the copper version hits on digital at 28, this one comes in at 6! I played around comparing targets and the perfect match for screen reading and sound turned out to be a cast brass button. I am fairly confident it has to be a metal other than copper but I have to find out for sure.

A quick follow up question...

Do you think a coin could be chemically altered to have a drastically different sound? ... and that's keeping the condition of being very readable on both sides and not really corroded. That's the only other explanation possible for this to be copper.

 

[Nick A]

All kinds of alloys can be used in brass and copper. The older the token, the more variation is possible in the mix. And especially with tokens over coins. Coins have specs they had to keep to... x % copper x % tin, etc... Token makers could use whatever metal they wanted. Very few coins or tokens are pure 100% copper. Factor in ground effects of corrosion as well, I don't think the variation is significant. I am 99.9% sure you have the regular copper token.

 

[Iron Patch]

All kinds of alloys can be used in brass and copper. The older the token, the more variation is possible in the mix. And especially with tokens over coins. Coins have specs they had to keep to... x % copper x % tin, etc... Token makers could use whatever metal they wanted. Very few coins or tokens are pure 100% copper. Factor in ground effects of corrosion as well, I don't think the variation is significant. I am 99.9% sure you have the regular copper token.

They were struck at the The Birmingham Mint so I think the quality control might be a little better than you suspected. I scanned 20 more of the same token and all were in the range of a penny. I bet i could scan 500 more and all would be the same high reading. I added the second question to my post because to me that's the only thing that would make sense.

If enough of an alloy is mixed with copper doesn't that mean it is no longer copper?