Verdigris and gold and silver

anyone have their gold or silver coins that had verdigris on it? post your experience here

 

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Verdigris is oxidized copper, so by definition you wouldn't see it on a silver or gold coin unless the metal was debased. When silver oxidizes it's called tarnish. Gold doesn't oxidize at room temperature, so no worries there.

 

well some of the silver coins that were given to me recently had verdigiris on them and it seems like i work for NCS or at least i should i am tired of removing verdigris on coins 1000+ and counting so thats why i wanted to hear peoples experiences.

fish,

most silver and gold coins have some amount of copper in them

 

In reality your sort of correct. It's just that people that don't know, use expressions they've heard somewhere such as PVC damage and/or Verdigris. Verdigris is (CH3COO)2 and is normally called an acetate. The reason is it is created by the attack of something like Acetic Acid on Copper.
And true Silver Nitrates and Oxides are called Tarnish and since this metal reacts so readily with other substances, the discolorations can vary. A Silver persulfate Ag2(SO5)3, for example could be confused with Verdigris.
This is true of Gold. For example although Au2S is actually a Br/Bk discoloration, AuCl3 too is a discoloration, some may well just say things like
VERDIGRIS. Others say it's PVC.
Of course it's true that most coins do contain Copper but usually an insufficient amount and not in a great location molecular wise to become attaced by an Acetate.
Then too the government may be telling us our coins that are supposed to be Silver or Gold are in reality Copper and painted to look like that.:goofer:

 

Fish, you shouldn't see verdigris on .999 silver or .999 gold coins as the amount of copper possible is too small. On coins that are less, say 90% silver ,10% copper, verdigris can occur along with the silver corrosion compounds. I bought a NCG MS69 1/10 oz 2000 AGE ( 91.7% gold) at the club auction, and there are copper spots with visible "centers", tiny specks of something bad that initiated the corrosion. I would have thought the coin would be dusted or something before encapsulation. The copper spots are not the greenish verdigris color as gold being a noble metal does not combine with copper, but just "mixes" molecule wise. So the discoloration is the separate copper molecules reacting (corroding) and not the mass one has with 90% silver or cents. Thus the surface diffraction layer should be thin enough to only show a tint of darker yellow to light reddish color. If gold actually bonded with the copper, 90% gold coins would probably show the "greenish" color of verdigris also.

Jim

 

I am positive you have seen more gold coins than I have, and it is possible, but much less likely I think. I guess I should have added or commented on the part posted about debasement or even more primitive methods of mints combining the gold and copper which could lead to "clumps" of copper molecules large enough to support verdigris formation. I think I recall a similar thread where someone had bought some copper spotted gold coins hoping to remove them and regrading.

Hey, are you going on any vacations in the next few days/weeks? Driving race cars? meeting Spock in person ? Playing poker with Jack ?:whistle:

Trying to come up with my 20,000 post guess

Man you are the 800 lb gorilla on the forum! Really appreciate your comments!


Jim

 

well at the risk of sounding repetitive i am literally up to my eyes in silver covered verdigris and its not fun.

 

hahah GD a gorilla and that makes me the gorilla trainer i suppose

 

You're right, older coins that had a higher percentage of copper did, at times, tend towards imperfect mixtures that would show corrosion. I shouldn't have glossed over that point. Carl's post was a delight to read, it's nice to see chemistry come into things.

If your silver with "verdigris" on it cleans up in pure acetone, it was PVC damage. You should be able to get pure acetone at your local hardware store.

 

unfortunately it cleans up in biox instead

 

you are my mirror image if you can call it that :whistle:

 

GD, sorry if it is involuntary. Tough times to get work. Personally I am not welcome to go back to my former employment. They didn't like it much when I told them their equivalent of a favorite coin was cleaned, scratched, dented and counterfeit! Really p**sed them off at the time . My fellow employees still love me, but the presidents have this secret book they pass down to each other.........:secret:

Jim

 

i must be seeing things. since when has a gold mine owner needed a job? and you have a gem mine to boot. if i were you it would take more than wild horses to drag me to work

 

Dont clean your own coin!!!

There are several different methods to remove verdigris that I have come across cleaning ancients (its a common problem in that area) but I fear that to pass on information regarding cleaning coins is irresponsible and I would be aiding you, a person who dont know what they are doing, to ruin your coins. As I dont want to help you ruin your coins I must give you the BEST possible advice that can be given...dont clean them yourself, send them in to a pro and pay for them to be cleaned...you dont know what you are doing (even if I spelled it out step by step) and you could ruin the coin and I cant have that one my consience. It would probably be nice if there were a nice informative website that gave these methods but then that would be irresponsible.

so my advice would be one your are familiar with...dont buy problem coins, if they develop problems, seld them in to be conserved by people who know what they are doing, you cant be trusted to conserve your own coins.

Knowledge...you cant be trusted with it....

 

does the library chap manifest into other identities too? I wonder ...... or maybe verdigris has side effects that havent been documented yet

 

Verdigris on 1oz krugerrand

Hi.

I'm new to the forum and I'm also new to coin investing.


I ordered my first bullion coins and went for among others Krugerrand (1oz). Krugerrand has as you might know, a layer/amount of copper that makes the coin less susceptible and supposedly more suitable for circulation.

When I took it out of the zip bag the other day I realized it had verdigris in it's lower corner... the green spots and all and a discolored zone around it. The other side of the coin had the discoloring in the same area but without green spots.
Is this bad and can it destroy the value of the coin?

The seller writes about their Krugerrand 1oz:

These coins have been in circulation, scratches may appear.

So obviously they are not brand new. Although it technically has no scratches. But should I accept the verdigris and believe the coin will maintain it's buy back price. Or is this an obvious refund situation? What do you experts think?