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 Replies: 7 / Views: 2,045 |
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New Member
United States
5 Posts |
I found a 1988 20 Pesos coin that has a shiny chrome-like finish, instead of the expected yellow brass color. In the background areas there appears to be the remnants of brass plating that has mostly worn off. In the photos it is placed next to normal brass 1988 20 Pesos coins. Diameter and weight are roughly the same as brass coins (my scale is only accurate to nearest gram). The coin is non-magnetic, and it doesn't look counterfeit (I say that because it appears well-struck and not cast. My guess is that it was struck from a copper-nickel planchet that had a thin brass plating. I can't find anything online regarding such an error coin. For the year 1988, over 355 million 20 Pesos coins were minted, so I am surprised that I can't find any reference to similar errors. Has anyone seen a similar coin of a close year/denomination?    |
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Pillar of the Community
United States
634 Posts |
it likely has a silvery coating that is coming off.  to the CCF! Edited by Illegaltender
03/31/2017 9:33 pm
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New Member
 United States
5 Posts |
Given my description of the coin, and the photos, it makes sense to question if the silvery coating is coming off. An 'up close and personal' examination of the coin, however, indicates that there is no silvery coating coming off the coin whatsoever. The brass color in the background - what I suspect is brass plating - is definitely what is coming off the coin.
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Pillar of the Community
United States
634 Posts |
Weigh it and another regular coin. That might give us clues
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New Member
United States
5 Posts |
I weighed the coin and several other regular brass ones, and it weighed 6 grams like the others. The trouble is that my scale is built for weighing mail and packages, so it's only accurate to the nearest gram, and that's not very helpful for this task. Tomorrow I will seek out a more accurate scale. I definitely agree with you, Illegaltender, that comparing weights will lead to an answer of some sort. Thanks for the suggestions!
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New Member
United States
5 Posts |
Well, I bought a new scale, and the weight of my special coin is right about 5.85 grams, which is just about what all the regular brass ones weigh. This seems to point to the conclusion that I have a brass coin after all, that's just a weird color. However, I don't know enough about metals to accept that conclusion just yet. That is, I have suggested that my special coin appears to be made of copper-nickel, and appears to be the same size as a regular brass coin. If we compare a 20 pesos coin of copper-nickel to a 20 pesos coin of brass (which is actually just copper-zinc), at what decimal place would the weights differ? I have no clue. I suspect that for small, same-sized coins, the weight of a copper-nickel coin is very close to the weight of a copper-zinc coin. That's just a guess, though. Ideas anyone?
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Pillar of the Community
Australia
3831 Posts |
Looks like it has been cleaned. Cleaned brass does have that look.
My partial coin collection http://www.omnicoin.com/collection/gxseriesMy numismatics articles and collection: http://www.gxseries.com/numis/numis_index.htmRegularly updated at least once a month. |
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New Member
United States
5 Posts |
Thanks for the suggestion. In an effort to avoid any loss of value to the coin, I have refrained from cleaning or polishing it. While I haven't cleaned the coin myself, I did consider the possibility that a previous owner might have. I have done cleaning experiments with other 1988 20 pesos coins, and so far I haven't been able to produce anything close to the chrome color of my special coin (my poor quality photos make it seem to have more of a yellowish cast than it really does). Maybe I just need to find the right chemical to produce a similar effect, though. (I don't really want to produce a similar effect, because I haven't lost hope that I have the only coin out of over 355 million 1988 20 Pesos coins that is not made of brass. But I'm not going to let my optimism cloud my common-sense.)
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Replies: 7 / Views: 2,045 |
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Posted 03/31/2017 10:11 pm
