Please explain to me how Bronze coins achieve this color naturally.
keets
Posts: 25,351 ✭✭✭✭✭
The coin in question is a Two-Cent pc. from the below linked listing.
ebay.com/itm/1873-PF-Two-Cent-Closed-3-PCGS-PR65BN-Rainbow-Toned-Registry-Coin-600-Minted/371873770334?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D41376%26meid%3D93711bcead7242a898b735f62fe99d35%26pid%3D100033%26rk%3D1%26rkt%3D8%26sd%3D371873770334
Al H.
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Tissue paper, which has been invoked as the explanation for proof Indian Head cents having blue coloration.
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
Ms-70
Knowledge is the enemy of fear
Yes, I forgot about MS70.
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
Naturally my A$$
IMHO it looks AT
Coins for sale at link below
https://photos.google.com/album/AF1QipOVMv7FZDb2BvqQnSIUKnelz2nhX9TVEMcKHgHm
Not all but most blue coins raise my suspicion.
Somebody find Rick Snow's recent thread on blue toning.
As to this coin, I see no reason to doubt that the toning is natural, but not having seen the piece in hand I cannot say if it is or is not.
I was going to suggest the same. Rick has some very firm views on this with which not everyone agreed. But it was an enlightening thread.
Lance.
No way to tell unless you owned it before it toned.
Blue is the most common naturally occurring color but also the easiest to assist.
If you like 'em buy 'em, If not don't is the only advice I have.
The blue around the devices looks odd to me. It's flat on the fields and then builds up a fuzzy kind of intensity by the fields. I don't recall seeing this on coins with less blue color but I don't look at super sized photos of these that often.
Here's an image using the PCGS link so the image doesn't go poof when eBay kills it on their side.
Rick presented some interesting assertions that I wasn't able to duplicate, so I don't agree with his premise(s) at all.
We'll the answer is that we normally see brown-toned coins with a film of oil or accumulated debris or even PVC. I have shown in the past that if you take a coin like this and coat it with oil (blue ribbon, finger oil, PVC) or just leave it in an environment where it can accumulate surface contaminants, it will revert to the normally seen brown color we are used to.
It is stripped of the naturally occurring surface oils that a 150-year old coin accumulates when stored in a paper envelope. It is natural toning but we are not used to seeing it without the surface contaminants that are easily attracted to copper coins.
I have a feeling the coin in question doesn't like this in hand. Don't forget the true view is a glamour shot.
A coin with its ORIGINAL SKIn on it will never look like the color that is displayed on this coin.
A knowledgeable collector or dealer knows the TRUEcolors of coins that were stored in tissue paper from the mint . I will state 100% that this coin was chemically treated to achieve this color.
It SHOULD be graded AT ( artificial toning) but I don't run the grading company.
IMO a naturally toned coin must have never been chemically cleaned with Blue ribbon , MS 70 or any other oils to change the appearance of the coin
True original coins are scarce if not rare not matter what the population stated .They are worth a premium every time.
The coin pictured here is caca. It will never get a CAC sticker. If you buy It I will tell you it will be worth less in the future because these type of coin are manufactured and more will be made and graded.
Stewart
Personally, I like the look of "blue" copper like that coin, although I don't collect it.
Copper has a natural tendency to turn green and blue. The mineral Turquoise gets its color from the copper content.
As EagleEye noted, a film of oil and dirt on that coin could quite possibly change the color to brownish.
I've personally taken some brown unc Lincoln cents (not valuable ones) and put them in a solvent like laquer thinner or acetone. Once the dirt and oils were dissolved off of them, they came out with a bluish hue that they didn't have going in.
Hahahahahaha, you have a way with words!
**Copper has a natural tendency to turn green **
copper tends to oxidize to Brown, it tends to CORRODE and turn green. I understand that they are both really the same thing although the Brown is to my way of thinking a film of oxidation which prevents anything further from happening, corrosion which results in Green tends to be heavy oxidation. I believe the "green and blue" you refer to are nothing more than thin film interference that we see as tone and my experience is that they really don't look like this on coins unless they are achieved artificially.
the "film of oil and dirt" you mentioned(and which Rick also refers to here and in other threads) that you contend is hiding the color strikes me as a bogus claim if I consider what I have done to see the results. I have taken Brown MS/circulated Wheat Cents, stripped them by using acetone and treated them with MS70. the typical result is brown with bluish hues which vary in intensity. any subsequent rinsing in acetone DOES NOT remove the bluish tint so I am left to believe that the chemical(s) reacted somehow with the bronze and changed the color.
from what I have done and seen I doubt that the coin looks as intense as the linked picture shows, it is as USM6 said, a glamour shot. I interpret the picture as showing an RB coin which has bluish hue where it was originally brown and red-purple in areas which were protected and still retained Mint Red, around the lettering and devices. I bet it looks glossy in-hand.
I have to agree the coin has been touched with a chemical. I think PCGS is giving these coins a grade because they have become market acceptable, in fact some collectors are hunting these coins down. whether CAC will give it a sticker I do not know. One glaring thing missing from the coin in the OP is luster. I could believe the color may be original from being stored in an envelope IF the luster still existed. From the photo the coin, although a good strike and not worn, looks lifeless without its luster IMHO.
"A dog breaks your heart only one time and that is when they pass on". Unknown
Hmm> @1Mike1 said:
It's a proof. The surfaces should be reflective, not lustrous.
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
Not to debate Stewart on the desirability of original skin. We tend to agree. It is very important, even essential on full red copper to have original skin and not have anything ever disturb the skin of an original red coin. Once removed, it will turn red-brown or become spotted. That is not the OP's question though.
To paraphrase the question - "What made it blue?"
It is obviously not a full red coin which is what Stewart is an expert in.
It is a heavily patinated coin. It has a thick brown patina with a blue tone. That brown patina was acquired by long term storage in an envelope probably laden with sulfur. We're talking 50 years. Along with the brown came the blue toning, but if you ever saw a coin like this in its original envelope, which I have, you would see a dusty dirty brown coin with no mirrors evident. That's original dirt - or, if you want to call it skin, OK. The dirt that has accumulated on the surface is disrupting the thin-film interference that gives toning its color variations. Once you remove it, the colors come forth and so does the beauty of the mirrors. You could leave it with original dirt if you desire, but removing dirt to uncover the coins toning is not creating toning.
I'll use the scientific method to prove my point. Please try and make any old copper coin turn blue. I'll wait......sorry, I'll save you some time - you can't. It can't be done to a red coin. It can't be done to any old brown coin. If it can't be done to every copper coin, then the premise that it adds the color at all is wrong. It is only specific coins that will show the color. And the thing they all have in common is long-term storage in an envelope. I have tried to figure this out over many years and this is my conclusion. It is not an opinion, it is fact.
**And the thing they all have in common is long-term storage in an envelope. **
Rick, it isn't worth arguing the point, you have your experience and I have mine. I have used MS70 on Brown Cents and caused them to turn blue/purple and there is no reason to believe that the random coins I chose had been stored in an envelope. others have done the same thing out in Cali about 10-12 years ago. the evidence is undeniable, MS70 causes these coins to change.
have a nice evening.
Then why did you start this thread? Your mind was already made up and you wanted to stir something up? So, you lose an argument by saying, I have my "fact" and yours are your own? I don't think so. I researched this extensively because I wanted to know for myself what is happening. The proof to me was made when it could be shown that is not repeatable on just any copper coin (Proves it is not a reaction) and you can actually temporarily hide the toning's appearance by coating a coin with a thin film of oil (proves it is a factor of thin-film interference.)
It's been Margulied.
Exposure to the atmosphere is what turns copper coins to oxidize and turn brown. It is not a patina. Rather it is a disintegration of the skin on a coin.
Coins take on different tones of brown
Based on the planchette. Different mints in different locations cause different appearances. Contrary to this discussion,
Most copper coins were not stored in paper envelopes. They were exposed to the atmosphere and light.Patination on a coin is created with chemicals.
My gripe is when I sold the finest Red/ Brown proof 1916 Lincoln cent ( pr67 ) to Rick and Brian for $65,0000 and they then sold it for a profit.
Presently there is a blue Larry Shepard
1916 pr 67 + r/b that isn't worth Jack Schit.
IMO these blue coins ruin my market.
How do you remove the dirt? Is that what MS70 is for?
The Proof 2 Cent piece in the above auction only has that color viewable at very specific angles. I have an 1899 Indian Cent that is very similar. Under normal viewing angles, the coin is brown, but when tipped so that is reflects light directly off the surfaces and to your eye, it flashes a gorgeous iridescent greenish blue.
Here are images of it with the only thing changing between images is the lighting.
Here it is shot using axial lighting so that the light reflects directly off the surface and straight back into the lens.
Here is the same coin shot using traditional angled lighting.
And the reverse side.
Now if MS-70 could do this to a bronze coin, they would be everywhere.
What ever you name it, its not there.
"A dog breaks your heart only one time and that is when they pass on". Unknown
I have my doubts the coin displays that level of color in hand. I in no way am being critical of the PCGS photography... some coins are just tough to capture as they look.
Experience the World through Numismatics...it's more than you can imagine.
Wouldn't that be called doctored/manufactured?
This one graded...
This IHC developed some small PVC spots so I decided to give PCGS's new conservation service (new at the time) a try.
Typical treatment is an acetone bath or with a thinner like oxylene. I don't know what PCGS uses but I suspect it is something like this. Harmless to metal but good at removing organic material (like PVC but also oils from handling and environmental contamination).
I was surprised when it came back looking different and, back then, I concluded that whatever chemicals were used affected the toning color. I have come to believe otherwise. Rick and I did some experimenting a few years back, with MS70, Blue Ribbon, and acetone and he proved his point to me.
Lance.
That 1878 IHC came out of the bath even nicer.
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
Nice luster!
"A dog breaks your heart only one time and that is when they pass on". Unknown
Stewart, you may have your opinion on how copper coins come to be toned. But many of us also have an opinion on how copper coins that are over 100 years old are still red. They certainly have been exposed directly or indirectly to the atmosphere, but I seriously doubt that they have been stored in an oxygen free environment for the past 100+ years.
I would question that most IHC PR coins graded RD have not been dipped to maintain the RD. Copper is very reactively chemically and if you think that copper ( and bronze) does not react (somewhat readily) with other substances you might be speaking from emotion rather than science.
ALL copper will react over time. A copper coin that is over 100 years old will not look like the day it was minted. Chasing "original" copper surfaces as a collector is at best futile, because they just do not stay that way without dipping.
OINK
ALL copper will react over time. A copper coin that is over 100 years old will not look like the day it was minted. Chasing "original" copper surfaces as a collector is at best futile, because they just do not stay that way without dipping.
this is basically my premise, although I accept that there is indeed some old Copper which has been stored in such a way that the coin(s) retain the original surface condition and color. it is imply that some of the chemicals used to rejuvenate the surfaces of some coins enhance them, at least that is what I have found to be true.
Just to add a data point:
I have a 1942 Lincoln that resided in an old 2x2, I removed it because it seemed nice but had a thick looking layer of "something" on it. I thought it was PVC residue or soemthing and it felt waxy. Acetone absolutely wouldn't touch it, had it soaking for days. I hit it with MS70 and it removed the "something" that was on it and left behind a blue-surfaced coin. It is like Rick said above, at certain angles you can see blue, at others it's brown and if it is submerged in water or acetone you can't see the blue. Pretty interesting.
Collector, occasional seller
Turquoise - "The blue is attributed to idiochromatic copper while the green may be the result of either iron impurities (replacing aluminium) or dehydration."
Azurite - "Azurite is a soft, deep blue copper mineral produced by weathering of copper ore deposits."
Of all the colors to question a 95% copper coin turning, blue should really not be one of them. In nature copper is almost universally responsible for turning things blue. In the case of coins there are 1000s of different substances that these can come into contact with NATURALLY: paper, wood finishes, treated glass, gasses in a garage, felt, velvet, etc each made by 100s of different manufacturers over the 150 years of this coin's existence with differing chemical compositions.
This is not to say it couldn't be artificially produced but rather it is reasonable (even likely) that it could happen 100% naturally.
Interesting thread.
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I picked up this one from Rick Snow a few years ago........
Pretty sure that this coin is not the result of MS70.
OINK
And some, not necessarily me, would say the opposite.
Well, just Love coins, period.
getting toned copper in holders is a problem. IMHO I feel that the grading people really can't always tell.
So that leads me to believe that some in holders are AT and some that were not in holders are NT.
Its a fine line and blurry at best.
It is not at all hard to believe that old copper coins can retain much if not all of their original mint red color. Rolls many decades old often are filled with bright red cents (except for the exposed ends, perhaps).
I can imagine there are many different ways of storing copper cents that would achieve the same results. Shoot...I have red cents in rattlers that haven't changed in 30 years. I have an old album of wheaties with 70 and 80 year old coins that are still bright red.
I agree that ordinary exposure to the elements, and certainly circulation in commerce, will turn copper brown.
I would love to hear how a dip turns a brown cent red with convincing results.
Lance.
Two important rules in life:
Or the check is in the mail..:(
And a third:
3. Change is inevitable, except from a vending machine.
An authorized PCGS dealer, and a contributor to the Red Book.
And below we have and MS70 experiment, before MS70 shown, after using MS70 shown, and then the coin 3 years later. Still looks like the 2014 image today. So any types of blue coming from supposed MS70 reaction is not sustainable, the blue should go away under normal conditions - this experiment suggest that MS70 left behind a volatile compound that caused the blue that went back into the air over time.
MS70 is a strong oxidant, has a pH of 13.5, so any reaction with copper should be to produce an oxide coating on the surface - are such oxide coatings blue/purple etc.? I don't think they are. So sustainable blue toning on copper is probably not from an MS70 wash IMO..... I think what MS70 does is strip off patina, not react with the copper, and potentially can leave a volatile compound behind. It would be interesting to have a chemist look at this.
So I believe Rick's argument for the blue toned copper to be likely mostly correct.
Best, SH
So MS 70 is very alkaline, is it a detergent?
This > @EagleEye said:
I've only seriously ventured into copper coins the last couple of years, and can't hold a candle to either of your experiences with copper, but allow me to offer some things I've learned about coin toning.
To roughly summarize both of your points above: Full original skin copper starts out Red. From there it oxidizes and turns brown, doesn't patina, but disintegrates, turns browner. If the original red is disturbed, it turns brown or spots. A brown coin that is heavily patined can tone blue, and blue toning can't be faked.
The natural color of pure copper is salmon pink, orangey pink, however you want to describe it. With a newly minted coin, it immediately begins to react with oxygen in the air, as well as other 'contaminants' in the air, including sulfides. That oxidation process creates a patina on the coin, and can include a layer of copper sulfide. It is that reaction that creates a thin film interference, which results in colors seen on a coin. (Note that thin film interference is different than Morgans interacting with chemicals in canvas bags, or coins directly in contact with sulfuric paper 2x2s, and is not the only source of colors occurring on a coin.)
The colors seen from a thin film are affected by the original color of the coin, the thickness of the film, the view angle taken, and changes/chemicals applied to the metal.
Just like silver coins, copper colored coins have a primary color progression in thin film interference from thin to thick. It is: No Toning (salmon pink) - RED Copper - Burgundy - Dark Blue - Light Blue - Silver - Yellow - Red - Blue - Green - Yellow - Red - etc., all the way to Black.
The Red Copper color in the thin film interference progression is essentially what the TPGs call RD in their holder designation. A FULL RED coin is more or less a coin that has not passed the first stage of thin film interference. If a coin passes through the first stage, the coin's colors will turn to Burdgundy, then to Dark Blue, etc. So, it is absolutely possible that a coin with its original skin can develop a dark blue color. And Dark Blue is an earlier color in the thin film interference progression, meaning that it does not necessarily hold true that thick brown patina coins are hiding a blue color. Greens and reds are more likely to be underneath a brown patina. If thin film does not progress, and thus colors do not appear, a coin will likely continue to oxidize and continue to turn brown.
Copper coins do not, as a rule, only take on different shades of brown. Too many variables for that to be true. That is akin to saying that silver coins only take on different shades of grey, until they ultimately turn black. If an original red coin is disturbed, that means that it is highly unlikely to further develop any natural thin film, Thin film is usually seen as a natural progression of colors (think Lincoln cents out of a double mint set) where the sulfur content of the cardboard helped to create an array of colors. Monochromatic coloring is quite unusual for thin film toned coins. That is moreso seen with coins more directly and consistently exposed to a direct reactant, natural or unnatural as it may be.
And let the metallurgists, experts, etc. that I know are around these boards chime in better than I can, but it isn't too difficult to get copper to take on blue color.