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 Replies: 10 / Views: 2,822 |
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New Member
Canada
0 Posts |
I recently acquired a 1943 Canadian 5 cent piece which appears to be struck on a copper planchet, not Tombac. The size and weight is correct for the piece, it's just the unusual colour. I tried polishing a regular 1943 example to see if it was as a result of polishing, however it just took on a fuller brass look. I have posted images of obverse and reverse, beside a regular 1943 Tombac so you can see the differences (please note images were taken with my Blackberry so quality is a little poor). I am wondering: firstly if anyone else has run across a 1943 Canadian 5 cent piece with a similar appearance; secondly if anyone knows whether it is possible to chemically alter the appearance of a Tombac piece to take on a more copper like appearance; and finally if anyone knows if the Ottawa mint was producing any other Commonwealth coins in 1943, which might have lead to a blank sheet made for another coinage run, could have accidentally been mixed in with the Tombac sheets resulting in perhaps a few hundred examples being made? A curiosity I would like to find out more about and understand if it is real, a minting anomaly or something that that someone has created. You thoughts and inputs would be helpful. Brian Hobbs   |
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Moderator
 United States
188213 Posts |
 to the Community! I moved your post to the appropriate forum for the proper attention.  |
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Pillar of the Community
Canada
5324 Posts |
Get the coin xrayed with an XRF, if it's copper you have a really cool coin, forgot a happy welcome
Edited by john100
03/17/2017 6:16 pm
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Valued Member
Canada
97 Posts |
I have one similar, so I'd be interested to know what is up with these coins. Thanks for posting.
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Pillar of the Community
Canada
4911 Posts |
I've had similar coins as far as the colour goes..I always dismissed them as cleaned since although darker, they always had shinier surfaces than they should, much like your example..For a definite answer, contact our wonderful member SP-Ottawa, he is a wealth of knowledge and also has the equipment to test your coin, and he is also very trustworthy.
Feel free to call me Will.
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Pillar of the Community
Canada
5239 Posts |
You cannot rely on the appearance to determine composition. Metal tarnishes in odd ways, and the coin is supposed to be 88% copper anyway. I don't know how much effort went into ensuring consistency of the alloy. An XRF is really the only way to be sure. I would not be surprised if SP-Ottawa has done something already. In fact I thought that I saw an article he wrote recently on this very subject, unless my memory is completely messed up.
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Bedrock of the Community
Canada
10743 Posts |
..to CCF Brian..  We have a member here that can check your coin out if you want to send it to him.  |
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Pillar of the Community
Canada
891 Posts |
I think those coins are 88% copper and 12 % zinc, maybe a poor mix , the zinc gives it the brass color, SPP will know for sure |
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Pillar of the Community
Canada
1461 Posts |
I've seen these coins tone all different shades. I'm not sure what the tolerance in variance would be between copper and zinc for the coins themselves but as far as tombac itself, it can be up to 95% copper, 5% zinc. Maybe Roger can pick this up as a project...lol...
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Moderator
Canada
10458 Posts |
That is what tombac looks like, if you polish it and it retones...
"Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Bedrock of the Community
Canada
24885 Posts |
I bought those coins 10 years ago . All of them have a different shade I like very much this edition ..  |
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Replies: 10 / Views: 2,822 |
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Posted 03/17/2017 6:13 pm
