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 Replies: 11 / Views: 4,073 |
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New Member
Isle of Man
6 Posts |
I have a 1970 Proof Manx Cat Crown but cannot tell if it is silver or cupro nickel. The weights listed are almost identical and I don't want to break open the plastic sachet to do an accurate weigh. My coin is in a white leather hinged case.
Does anyone have the knowledge to help me on this please ?
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Bedrock of the Community
 United States
12477 Posts |
I know nothing of the coin, but the tissue test may work. A single ply tissue over the coin will show white if it is silver and more grey if it is CuNi. Comparing it to coins of a known composition is best. Here is a pic of that using U.S. quarter proofs. On the left are .900 silver and the right are CuNi:  P.S. That pic was taken through the plastic lens, so you shouldn't have to remove your coin from its holder to get results. A coin for comparison is a must. In Memory of Crazyb0 12-26-1951 to 7-27-2020
In Memory of Tootallious 3-31-1964 to 4-15-2020
In Memory of T-BOP 10-12-1949 to 1-19-2024
Edited by spru
02/04/2018 04:07 am
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Moderator
 United States
56855 Posts |
 to CCF.  very good idea. Let us know how it turns out. Maybe post a pic. John1  |
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New Member
 Isle of Man
6 Posts |
Thanks SprueTT. That is a novel idea but I feel I want something a bit more positive and not liable to misinterpretation. My crown was minted by The Royal Mint, so I will also see what they have to say. I may have to break open the plastic capsule and weigh it but the weight difference is very little between cupro nickel and silver. Another way is to leave the coin out to see if it tarnishes. I think they look much better with a little blackening of the silver, less "synthetic" but not sure if that affects value. |
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Bedrock of the Community
United Kingdom
17925 Posts |
Hello and As far as I know, all Proof 1970 IOM Cat Crowns were silver. The cupro-nickel ones were struck to circulation standard. I've got a cupro-nickel 1970 IOM cat crown and it's uncased. I doubt if cupro-nickel ones were issued in sealed sachets inside leather cases. Is it an official Royal Mint case with the coat-of-arms on it? The silver crown was only issued as a proof. Royal Mint proof coins at that time were struck to a very high standard and the field should be like a mirror - you should be able to see your finger-tips reflected in it. The cupro-nickel coins have a dull, matt surface. If you compare your IOM crown with a known silver proof coin and a known cupro-nickel uncirculated coin (even a newish 20p or 50p coin from change), which coin is it most like in colour? I also have a feeling that the edge milling on the silver proof is a bit coarser than on the cupro-nickel version. I've compared my 1970 Manx crown to my silver proof 1972 UK Royal Wedding crown, and the edge milling on the cupro-nickel crown is much finer. Edited by NumisRob
02/04/2018 07:14 am
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New Member
Isle of Man
6 Posts |
Thanks for your thoughts and time Numis.
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Bedrock of the Community
Canada
24885 Posts |
To the Forum.  |
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New Member
Isle of Man
6 Posts |
I will try and get a photo today but coins always look horrible through The Royal Mint plastic packaging. Not sure why they use it, as all my packets have deteriorated after 48 years dark storage. I might just cut it off or does that affect value? |
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New Member
Isle of Man
6 Posts |
I have spent an age uploading and downsizing photos. Finally got to the bit that shows green arrows. Tried clicking those and they turn white but when you click the next one they go back to green. Since I suffer high blood pressure, I have kicked it into touch but maybe they will appear when I close this.
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Bedrock of the Community
United Kingdom
17925 Posts |
Bam - here's a photo of my cupro-nickel 1970 IOM crown (on the left) and my 1972 silver proof GB Royal Wedding crown on the right (in its original Royal Mint sealed mylar envelope). You can see the difference in quality between the two coins. If your IOM crown is in similar packaging, then I am pretty sure it's a silver proof.  |
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Bedrock of the Community
United States
12477 Posts |
I promise, try the tissue test. There's a reason why it is hyperlinked on CCF and that's because it works. Take a known CuNi coin, preferably crown sized, and lay a tissue over that and your coin in question. Decent lighting is necessary, but you should readily see a difference if the other is silver (especially being a proof). Also, I don't know what the weights are for each, but the silver should weigh more. For U.S. coins of that size, the difference can be determined with a scale that measures to 1/10 gram. In Memory of Crazyb0 12-26-1951 to 7-27-2020
In Memory of Tootallious 3-31-1964 to 4-15-2020
In Memory of T-BOP 10-12-1949 to 1-19-2024
Edited by spru
02/08/2018 01:58 am
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New Member
Isle of Man
6 Posts |
Thanks Sprue and Numis, except I have a cupro nickel Royal Wedding Manx Crown with a high mirror finish, which is as perfect and shiny as a silver proof. I think the weight of the silver and nickel Cat crowns should be slightly different but Spinks, who were the agent for them, list the weight and diameter as being the same.
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Replies: 11 / Views: 4,073 |
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Posted 02/04/2018 04:12 am
