What is the difference between corrosion and toning?

[the_Thing ®]

Can it not be said that both are an altering (damaging) of a coins surface due to a natural process/elements?

[TomB]

Read the articles on my web site for a primer on the subject.

 

As a quick rule, corrosion leads to the ultimate destruction of the metal involved while toning simply produces a thin film of oxidized metal on the surface.

[K6AZ]

Tom is correct. Toning results in a very thin film on the surface, while corrosion actually eats into the surface of the coin.

[the_Thing ®]

so would toning be considered damage in your opinion?

[K6AZ]

so would toning be considered damage in your opinion?

 

Absolutely not. Toning is the reaction on the surface of the coin with it's immediate atmosphere, creating a very thin layer on the surface of the coin. Corrosion on the other hand eats (digs) into the surface of the coin causing pitting, which is damage.

[TomB]

I have no problem with someone considering toning to be damage, in their opinion, as it might negatively affect the eye appeal to the viewer. On a more objective level, it is certainly an alteration of the coin from its issued state. Is that damage? I don't know.

[the_Thing ®]

I'm wondering all this because I was reading in the issue of Coin World I got in the mail today about a rare large cent that was ID'd and sent to ANACS due to it having corrosion and ANACS will slab "problem coins". Its only my opinion, but it seems to me that if you hold the same standards to everything, toning would be considered damage to the surface of a coin, but to a lesser extent than corrosion. I don't think most collectors want to think of it as damage because they are "pretty" and want the coins slabbed. If the grading services that refuse to slab problem coins were consistant, they would refuse to slab toned coins. Just my simple humble opinion.

[TomB]

I think you're wrong and I will tell you why.

 

If you are willing to take that stance then every dipped coin is damaged as the silver that had previously toned is now stripped off of the surface and every circulated coin is damaged as the coin is not in the state of preservation that it was when it left the mint. That leaves nothing but coins that immediately fall off of a press.

[the_Thing ®]

Tom, I would say a dipped coin is damaged! Circulated coins of course show small scratches, nicks etc, but it also shows up in the grade they receive. Not that way with toning. Doing it "by the book", it just seems like toning would have to be considered damage, just like a scratch, nick or corrosion. Has PCGS or NGC ever said why they refuse to slabbed "damaged" coins? Seems like they are missing out on a huge market share. Is it because they want to be considered "elite"?

[TomB]

Scratches and nicks on circulated coinage do not form the majority of the determination of grade; the amount of wear forms the majority of determination of grade. In contrast, for both dipped and toned MS and PF coinage, scratches and nicks do form the majority of determination of grade.

 

Anyway, PCGS and NGC slab thousands of damaged coins, regardless of one's definition of damaged, they just do not readily admit it.

[the_Thing ®]

I take it you like toned coins? I remember when I was a kid, oh, some 25 years ago, going into our local coin shop. Toned coins couldn't be found. Nothing in the major periodicals about them and you didn't see them listed for sale. When did they really start to get popular?

[TomB]

They've always been popular within a niche market, just as they are now. Also, I would bet that if you went into most local shops these days you still wouldn't see many toned coins. I believe that the internet has made people much more aware of toned coins and has also made it seem like there are many more gorgeously toned coins than is true.

[the_Thing ®]

The local coin show here last year, which is coming up in August usually has about 100 tables or so. Only one table had a majority of toned coins. PCGS or NGC slabbed. One fool had 3 tables, with coins all slabbed by ACG. I don't know how he could bring himself face to face with collectors.

[TomB]

A few years ago I would see ACG-slabbed coins at every show, but I have to admit that it has been a year or more since I have seen one at any show I have attended.

 

One thing I would like to add about toned coins is that I believe the great majority are either neutral or negative in their eye appeal.

[the_Thing ®]

I think some of the most attractive toning is found on the early silver dollars.

[the_Thing ®]

Also, tradedollarnut sure does seem to have some outstanding toned coins, and the tradedollars are beautiful coins to begin with.

[TomB]

The ability to image the coin accurately also helps tremendously.

[spy88]

Circulated coins of course show small scratches, nicks etc, but it also shows up in the grade they receive. Not that way with toning .

 

Not sure if I understand this statement, but as written, the TPGCs do give or subtract partial/full points for "eye appeal" which is the same as saying toning. I don't personally agree with this practice as it is just too subjective (beauty is in the eye of the beholder). I do agree with NGC giving a star for what they consider exceptional eye appeal but beyond that, it should not make a 65 a 66. The grade should only be technical (strike, luster, free of contact marks) not subjective, and any premium a toned coin (attractive or not) commands should be left to the individuals that are interested in that particular coin with that particular "look". Course, there are people that say grading is subjective and I must agree even tho this contradicts my

 

IMO, this is the same as saying a red Vette is worth more then a white Vette even tho all else is exactly the same. Last I remember, Chevy doesn't add a premium for color differences.

[James_OldeTowne]

"damage" to me implies something undesirable. Toning is desirable, so it is not "damage". However, corrosion is definitely not desirable.

 

James

[jom]

Read the articles on my web site for a primer on the subject.

 

As a quick rule, corrosion leads to the ultimate destruction of the metal involved while toning simply produces a thin film of oxidized metal on the surface.

 

If IWOG is a member here I wonder how long it will be until he drops in to argue this? five....four....three....

 

 

jom

[BankNote1]

Attractive "damage"???

[Leothelion]

What is the difference between corrosion and toning?

 

Not much! Toning is corrosion! Patina, tarnish, oxidation, toning, silver sulfide, copper sulfide, however you want to call it, it's all corrosion. Some of it's pretty, most of it is ugly. To a degree, early coins are allowed more uglyness then newer coins. The 1943 copper cents may be an exception.

 

Leo

[nwcs]

I believe Sunnywood had a rebuttal for that ridiculous toning-is-corrosion article that will be in a forthcoming CoinWorld.

[Morgannut]

No guys toning is NOT corrosion. Corrosion is the result of chemical reaction of iron with water ions resulting in HYDRATED ferric oxide. This results in alteration and removal of iron ions into a new layered (pancake-like) water-oxide-iron lattace work of compounds that easily flakes or scales off the surface. The key point is the presence of the hydrated compounds may continue to change the original iron surface, because there's water ions in the lattace structure.

 

Toning is a very thin addition of sulfide compounds that is self limiting. There's no free water ions or sulfur to keep the reaction going contained in the toning. This protects the surface from furthur alteration by passing vapors unless there are more additional sulfur compounds added (ie. you store your collection in canvas mint bags or acidic paper).

 

Of course all Morgan dollars and some other silver coins were soaked in sulfuric acid after heating and just before striking. So mint state silver coins came as made with surfide compounds on the surface-- and all have some natural toning before they are released. If they don't, they're not techically in their "mint state"-although I agree that's a silly fine point.

[Leothelion]

No guys toning is NOT corrosion.

 

Perhaps you're right! Early on in my collecting years when I wanted to remove copper carbonate spots from my coins, I did a little research. One of the books I refer to is titled Cleaning and Preservation of Coins and Medals by Sanford J Durst.

 

His definition was; All naturally occurring chemical changes (incidental) of the metal surface, for the present instance, of coins or of the entire, should be classified as corrosion.

 

This makes sense to me when the surface of the coin does go through changes caused by chemicals or whatever enviorment it has been subjected to, however severe it may get.

 

Leo