Why do some colour like this?

[lara4228]

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I see thia more often with older Canadian copper pennies rather than US, but why do they colour like that? Why one and not another?

Thanks!

Lara

[jfines69]

The pics are a little blurry to tell but it appears to be environmental damage which can discolour the coin... Is there any pitting???

[Maineman750]

Coins are pretty much like people, they age differently because they are exposed to different environments.

[lara4228]

Roger, in reply, I ask a redundant question. For coins that naturally tone, would be the same? Is that why some coins are considered red, red/brown?

I am sure I have asked this before a few years ago, but it has left me :/

Sorry

[Maineman750]

Lara, in order for a coin to tone "naturally"...it would really need to be in a controlled environment. Almost anything can effect toning...something in the air, what kind of container, flip, or album it is stored in...moisture, sunlight, etc..
The term red is more or less how much natural color remains from it being mint state although they do allow for other factors as long as they don't believe the coin to have been toned on purpose.

[jfines69]

If I remember my metals correctly if it is Red the makeup is more towards the brass end of the copper alloy mix and brown is more toward the bronze end of the copper alloy mix??? Straight copper would turn green???

[willbrooks]

Lara, in order for a coin to tone "naturally"...it would really need to be in a controlled environment.

You do realize the inherent contradiction there, right? Natural is the exact opposite of being in a controlled environment. Being in a controlled environment is actually the definition of un-natural toning. Now, don't get me wrong. I do know what you are really saying and I agree! Numismatically, we tend to accept certain types of toning and not others. But the fact is, all toning is due to the introduction of harmful "contaminants." Some are intentional, some aren't, but as Jody recently pointed out, all toning is corrosion. We just tend to accept certain types of it, like when the paper that the mint wrapped the coins in turns the dimes blue and the half-dollars yellow. (I have set like this I should post sometime.) It isn't natural at all. The paper did it. Yet people eat these up. Yet, when a coin is TRULY naturally toned and someone digs it up with their metal detector, nobody loves it so much. lol. The whole "natural" toning thing is a fraud, like many aspects of numismatics. As with any art, whether made intentionally or not, you just have to decide what you love and assign a value to it, because, ultimately, you like looking at it.

[Maineman750]

Yes Will, I do ....and it's much like determining what is collectible

[lara4228]

Oh boy. So Canuck Lara is a wee bit confused then...the coin I posted (and I have managed to have one from each era in the wheaties) resemble a red paint coat-like layer on it.

Now, I know it isn't paint. And I generally see this more often on Canadian cents than US. However, I do know that it is from natural occurance and intentional altering.

I am wondering if what Jim says sounds the truest...is it the percentage of the alloy (copper...brass) when mixed with other natural elements (air for example) turns a coin deep red or deep brown?

Is this what people refer to as "red/brown"?

[Maineman750]

emains from it being mint state [/B]although they do allow for other factors as long as they don't believe the coin to have been toned on purpose.

OK...let's try less clutter

[jfines69]

Oh boy. So Canuck Lara is a wee bit confused then...the coin I posted (and I have managed to have one from each era in the wheaties) resemble a red paint coat-like layer on it.

Now, I know it isn't paint. And I generally see this more often on Canadian cents than US. However, I do know that it is from natural occurance and intentional altering.

I am wondering if what Jim says sounds the truest...is it the percentage of the alloy (copper...brass) when mixed with other natural elements (air for example) turns a coin deep red or deep brown?

Is this what people refer to as "red/brown"?

Once the copper or copper alloy (brass or bronze) is introduced to the environment oxidation begins to occur... Due to other contaminants in the environment (Such as oils from human hands) brass will turn a red hue and bronze gets the deep brown with some green hue highlights and copper will turn green hues!!!

[Maineman750]

Is this what people refer to as "red/brown"?

No, it is not....your coin would not be slabbed as red or red brown....those designations are reserved for coins with luster...usually MS

[jfines69]

No, it is not....your coin would not be slabbed as red or red brown

I missed that... Thanks for covering it!!!

[BadThad]

You do realize the inherent contradiction there, right? Natural is the exact opposite of being in a controlled environment. Being in a controlled environment is actually the definition of un-natural toning. Now, don't get me wrong. I do know what you are really saying and I agree! Numismatically, we tend to accept certain types of toning and not others. But the fact is, all toning is due to the introduction of harmful "contaminants." Some are intentional, some aren't, but as Jody recently pointed out, all toning is corrosion. We just tend to accept certain types of it, like when the paper that the mint wrapped the coins in turns the dimes blue and the half-dollars yellow. (I have set like this I should post sometime.) It isn't natural at all. The paper did it. Yet people eat these up. Yet, when a coin is TRULY naturally toned and someone digs it up with their metal detector, nobody loves it so much. lol. The whole "natural" toning thing is a fraud, like many aspects of numismatics. As with any art, whether made intentionally or not, you just have to decide what you love and assign a value to it, because, ultimately, you like looking at it.

This is well written! This is why I really, really hate the terms NT/AT, those terms are a fraud. As far as toning, it's either "market acceptable" or "not market acceptable". On the TPG side, IMO, their criteria is simple, it all comes down to whether or not they want the coin in one of their holders. If it doesn't have a market acceptable look (in their opinion), they will not slab it, regardless of the toning source. I've seen dozens of rejected coins over the years, most of them I disagreed with the TPG (and so did my local dealer).

[BadThad]

To the OP - I've seen this "red" color on a lot of Lincolns. It is NOT what we refer to as red, as Maineman stated. As far as the origin of the color, nobody really knows. We would simply refer to this color as the "patina".