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 Replies: 10 / Views: 3,111 |
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Pillar of the Community
Turkey
870 Posts |
Hello guys.. this is my first post. .I come across the forum while searching information on Verdigris on copper coins, something which I wasn't totally aware of a week or so ago.
I went through my bronze UK and Ireland doubles (that I put inside a glass jar and keep them inside a drawer) and found some of them having :
1-) Bright or dull green spots on one or both sides of the coins.
2-) green patina, generally dull green over a big part (less than a half, sometimes about half) of the coin
3-) in Uk Bronze pennies, halfpennies or farthings, some very little greenish (generally dull, in some coins, bright) irregular spots between letters (mostly on the title of the King) though, very little.
4-) Dullish white, salt-like patina on some of the Ireland big pennies and halfpennies
First thing that come to my mind is verdigris of course. The coins I am talking about are mostly low-value, circulated coins, 1920's to 1960's halfpennies, 1900's to 1960's large Uk Pennies and some Irisih pre-decimal coins, though they're precious for me. I am not picky about their condition, however, I don't want them to rust away and got entirely destructed. Sicne I am living in Europe, I don't know if I can buy verdi-gone, as I red it works pretty well on Bronze coins (on the forum). I also red there are two types of this greenish thing, active and non-active, and the former being dangerous. based on my observations, can anyone comment on what is going on with my Bronze coins?.. I'll try to attach some pictures as well
Thank you for your time trying to help&reading this.
At least please take some time to look at the pictures and tell me what is wrong with those coins and can they be saved in a sense?.. Edited by molydeii
08/27/2009 8:25 pm
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Pillar of the Community
 Turkey
870 Posts |
Edited by molydeii
08/27/2009 12:32 pm
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Pillar of the Community
Australia
2830 Posts |
G'day and welcome, I visited Turkey in 1987: loved it, especially Istanbul. I'm not a chemist, and I'm not very knowledgeable about "coin cancer", but I suggest that you examine all of your copper and bronze coins carefully. I suggest that you quarantine the infected coins from the non-infected. I've never seen a definitive statement that verdigris from one coin can cause it in another coin ... however some of us think that that is a real possibility. Therefore, you ought save those that can be saved by separating them. You may as well experiment on the others, because their numismatic valued is minimal. I have read a story of someone salvaging an Australian penny from "Green Disease". Here is a link, that might lead you to that story: http://www.triton.vg/cleaning.htmlPeter in Darwin |
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Pillar of the Community
Turkey
870 Posts |
Thaks for your answer Peter, I probably experiment on some of those coins over this weekend. They're inexpensive and common coins, yet, they're valuable for me since I am basically a hoarder, as the term suggests.:) 1987, a long time! I am glad you liked it.. you'll definatey find Istanbul has changed a lot. It's even better now what is used to be, except the traffic which still is a killer :s Australia and new Zealand is two places I haven't been yet but I would love to visit there! maybe one day who knows:) About those coins, I seperated some, and put them inside olive oil.. and seperated some more, and put them into distilled water.. will wait for a week and see what will happen.. I am not worried about highly "green" coins, I'll probably use a chemical cleaner to prevent them at least from getting more green (thus runing the numismatic value.. but at least saving them in a sense). I am more worried for coins that have very tiny green dots on them, usually one or two, mostly between the letters of the title ( Georgivs VI D:G:BR...etc. part I am talking about).. I am including a picture, this will be my verdigris 101 course, can anyone please examine the photo and tell me which one of those coins have verdigris and whick ones doesn't.. I can't quite tell the difference when the area is too minor or the green colour is not too bright... I appreiciate your time on this people, thanks.. Here is the link. : http://img42.imageshack.us/img42/8316/1008676.jpgEdited by molydeii
08/28/2009 09:20 am
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Moderator
 United States
23731 Posts |
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Bedrock of the Community
United States
19935 Posts |
Welcome to CC!
You have early stage verdigris. VERDI-GONE™ would likely work very well on those coins. I don't recommend doing anything harsh to them or you will destroy the patina. The best thing you can do at this point is to soak them in acetone, dry and immediately put them into an airtite container with some dessicant packs. That will stop the verdigris where it's at, it cannot "grow" without moisture.
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Pillar of the Community
Turkey
870 Posts |
thanks for the suggestion BadThad.
I would actually love to try verdigone on those coins but I am not living in the states so I presume postage price will be really high :(
I am not experienced in bronze coins, can someone please examine the picture I uploaded above on my last post and tell me which coins have anything harmful on them, like verdigris or such.
I have tried to include coins with different problems on them
thank you all
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Pillar of the Community
Turkey
870 Posts |
Hello all, Can't anyone spare two mniutes to check the photo and tell me exactly which coins are damaged with verdigris?.. I have uploaded examples of several types of colouring/green/white patina.. I am asking this because I think I need to know how to "recognise" the enemy.. Guys, I really appreiciate someone helping me on that Thank you. http://img42.imageshack.us/img42/8316/1008676.jpg |
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Moderator
Australia
16808 Posts |
"Verdigris" is the term usually applied to green stuff appearing on copper or bronze coins. Basically, if it's a modern copper coin (less than 500 years old) and it's green, then it can be said to have "verdigris".
All verdigris is corrosion, but some types are worse than others. "Bronze disease" is the worst, most contagious kind. It usually manifests as a pale green or pale blue colour, crumbly or dusty appearance, and can spread, both across a coin and can jump from coin to coin if the coins are kept together in a jar or bowl. However, as Badthad said, if you seal it up from the atmosphere, it shouldn't spread.
On the coins in the link you've just provided, the ones I'd be most worried about are Row 1 numbers 2 and 3, R2 No1 and R3 No3 and No4.
I've never heard of contagious verdigris forming on cupronickel coins. Typically, cupronickel is muck harder to corrode. So the two silvery coins in row 3 have "environmental damage" (R3 No2 looks like "roadkill") but now they're removed from that environment, they're safe from further damage.
The dark staining on many of the other coins should be harmless (though unattractive) toning. The discoloured blotch on R2 No1 looks to me like it might be heat-damaged, and some of the other coins appear to have environmental damage (eg. R1 No1 and No 4).
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Pillar of the Community
Turkey
870 Posts |
Sap, thanks a lot about your explanations, now at least I know how to recognise the "enemy". I'll check once more the bronze and copper coins I have and immedicately seperate the ones that looks like the ones you identified as the "bronze disease". I don't want my other coins to get diseased like the ones that are dangerous. Once again, thank you for your time and detailed explanation for me.
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Bedrock of the Community
United States
19935 Posts |
Quote:
I've never heard of contagious verdigris forming on cupronickel coins. Typically, cupronickel is muck harder to corrode. So the two silvery coins in row 3 have "environmental damage" (R3 No2 looks like "roadkill") but now they're removed from that environment, they're safe from further damage.
All verdigris is "contagious". As long as air and water have access to the coin, everything is fair game. Existing verdigris can provide feed materials to another coin quite easily. Either through direct contact or via the gaseous state. Here's a quote from my upcoming book: Quote:
In some ways verdigris is much like a virus. It's obvious after looking at the chemistry involved that it can spread from coin to coin by contact. It's a simple matter of the verdigris infected coin being a donor of the corrosive elements. Since verdigris is an active spot on the coins surface that is constantly undergoing change based on composition, hydration and temperature, the chemical equilibriums dictate that some of the counter-ions (acetate, hydroxide, carbonate, etc.) will be present. If that verdigris stays in contact with a fresh copper surface, some of those ions will naturally migrate. Once they have moved to the new surface, cupric compounds will start to form producing new verdigris. As the spot is continually fed by the donor coin and by exposure to air and water, the verdigris will grow. Isolation of coins from the verdigris feed materials is of utmost importance to the numismatist!
Collectors should always separate verdigris infected coins and quarantine them! They will act as a catalyst for the continual formation of verdigris via ion migration.
Lincoln Cent Lover!VERDI-CARE™ INVENTOR https://verdi.care/
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Replies: 10 / Views: 3,111 |
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Posted 08/28/2009 02:38 am
