@keets said:
with regard to copper and color, is blue really a stable color for copper in the natural world??
I think that would depend on what the definition of 'stable' is. Years, decades, longer? Would also depend on what environment the copper is in, perhaps in a slab with limited air exchange it is more stable, but Cu is a very reactive metal.
ronyhaski, you posted "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."
On what evidence is this based? Published research? Your own experiments? I don't intend to sound like I am challenging you, but when one makes an authoritative sounding statement like this, I think there should be a firm substrate of facts. Your extended post clearly shows an intense interest in this area.
thanks,
Kaz
?"Copper coins do not, as a rule, only take on different shades of brown...." I don't agree, they do in fact generally DO turn different shades of brown eventually and that other colors or preservation of original red are more the exception. How many bags of wheaties does it take to prove that point?
Original "skin" is IMO a poor term as it is but the surface metal alloy that certainly can be variably oxidized in such environments; there is nothing per se special about this so-called skin. I do agree, and do not attempt to venture an explanation that it seems previously somewhat stable surfaces that are once again destabilized by dips or oxidants do seem to retone in the manner described.
Also, I wanted to revisit the "oxidation" of MS 70. I guess that we did not learn in chemistry that this was the case. Base pH yields a dearth of protons/ + charges in solution, a tendency to REDUCE therefore.
I am not understanding how multiple previous tests reported in many places did demonstrate purple/bluish tone imparted to copper coins after MS70 treatments, and now the claims are being forwarded that this does not occur. I have not purposely gone out to test this, but will note I have had one cent pieces turn what is apparently purple and have the same thing noted with British farthings, both of the pre-1860 copper type, and the later "bunhead" bronze alloy pieces.
Love that Milled British (1830-1960) Well, just Love coins, period.
So many experts, so little knowledge. There are so many variables it is ignorant to generalize.
What about wood grain toning on 1909 Lincoln cents ?
Has anyone ever seen a blue 1909 Lincoln cent ?
S mint Lincoln cents in the 1920's will most likely be softly struck and appear brassy in mint state.when well struck they appear cherry red.
None of these dates will ever appear blue unless chemically altered.
@keets said:
**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.)
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
Sorry to say the 2014 version looks like it has been attacked. From your photos the coin in the before photo looks much nicer. Makes me wonder how many times a coin could be "touched up" with MS70 before the blue stops showing up.
"May the silver waves that bear you heavenward be filled with love’s whisperings"
"A dog breaks your heart only one time and that is when they pass on". Unknown
@keets said:
**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.)
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
Sorry to say the 2014 version looks like it has been attacked. From your photos the coin in the before photo looks much nicer. Makes me wonder how many times a coin could be "touched up" with MS70 before the blue stops showing up.
The before photo shows a heavily patinated copper half cent. What does not show up well in the images is that this coin was wiped and parallel hairlines are present on both obverse and reverse - hence a no grade with PCGS and a details grade with ANACS prior to me cracking it for the test. But like all coins, it probably went through many 'touch ups' before it got to me, and that might also dictate how MS70 reacted with it. HST, the coin in hand today after removing the patina with MS70, and after the blue disappeared, is tremendously nice, except for the parallel hairlines...
@STEWARTBLAYNUMIS said:
So many experts, so little knowledge. There are so many variables it is ignorant to generalize.
What about wood grain toning on 1909 Lincoln cents ?
None of these dates will ever appear blue unless chemically altered.
What about wood grain toning? Whether it results from improper planchet alloy, contaminants on the rollers, whatever, how does that factor into natural or fake blue toning? Here is a coin with wood grain toning, with blue toning in it.
@STEWARTBLAYNUMIS said:
So many experts, so little knowledge. There are so many variables it is ignorant to generalize.
Has anyone ever seen a blue 1909 Lincoln cent ?
.
None of these dates will ever appear blue unless chemically altered.
YES, you haven't? Do you believe that these are all chemically altered?
@STEWARTBLAYNUMIS said:
So many experts, so little knowledge. There are so many variables it is ignorant to generalize.
S mint Lincoln cents in the 1920's will most likely be softly struck and appear brassy in mint state.when well struck they appear cherry red.
None of these dates will ever appear blue unless chemically altered.
Here is a 1926-S with blue toning in it. Do you believe that this coin has been chemically altered? ( Full disclosure: I own this coin.)
Some refer to overgraded slabs as Coffins. I like to think of them as Happy Coins.
Ronyahski - First, you need to understand what is wood grain toning
Second - Every coin you displayed including your 1926 s has been chemically
Altered.
Azurescens - nice coin ,gorgeous color and totally original
Afford: Trust me, in hand the coin does not look like this
CoinKat: I have my doubts the coin displays that level of color in hand/
Whether the pictured coin is truly blue is beside that the point of this thread, as I understand it.
I have seen many 99+% copper and 95% copper coins with blue tones, sometimes strange deep blue tints that seem encompassing. In many cases, the blue tones are the result of deliberate artificial toning. On early copper coins, blue is sometimes a byproduct of treatments of corrosion, with oils or other substances. On occasion, natural blue tones may occur. Natural blue tones on small cents are somewhat uncommon and many blue tones, particularly on Indian cents and Lincoln cents, are AT.
Rick: That brown patina was acquired by long term storage in an envelope probably laden with sulfur.
I disagree. There is a chemical tendency for copper coins to turn brown. They do not have to be in an envelope or exposed to much sulphur for this to occur. There are countervailing tendencies as well, though the tendency for copper to turn brown and eventually green (not blue) is powerful. Almost all coins are toning every day, really every slice of time. For most coins, the process is so slow that toning is not noticeable for many years or decades.
Rick: 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.
No, coin doctors frequently add blue color to copper coins. Others do as well, through treatments for corrosion and/or with substances that are believed by the users to be harmless.
Keets: 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.
Although I have never used this "MS-70" product myself. Keets' remarks are consistent with what I have been told by sources that are usually reliable.
Stewart: IMO these blue coins ruin my market.
Coin doctoring is a danger to all markets for rare or scarce coins.
Let us get back to the OP's original question, How did this coin turn blue naturally?
And the answer is that it was exposed toAmmonium Hydroxide Vapor. This color did not come from sulfur in paper envelopes as has been commonly believed. Nor have these coins been dipped to create this color artificially. When I Googled copper compound colors, and how to create them, bluish and redish patination have a common ingredient in the agent used to create this effect........ammonia hydroxide. Ammonia hydroxide is ammonia gas in water solution. It will exist as liquid and vapor in this form, but ammonia gas only exists as a liquid at high pressures. Soooo, how did these coins become "doctored" with ammonia vapor?
Before the creation of Mr. Clean and 409 in the 1960's, the most common cleaning agent in houses and commercial buildings was ammonia in a water solution, ammonium hydroxide. I remember my mother cleaning the house with ammonia (as it was called) and the house would smell of ammonia for a few hours. And this would happen at least once a week. In my business we build ammonia refrigeration plants. Copper is so reactive with ammonia that you cannot use copper in contact with pure ammonia gas. The copper will just corrode away. I even found a method to create blue copper by suspending a copper sample above a paper towel saturated with ammonia hydroxide in a closed container. Expect results in 2-3 minutes to 2-3 hours depending on how much blue you desire. I will try this on some low value coins.
Rick Snow's research provides great historical perspective to this issue. It was found that the Proskey hoard of proof Indian Cents were mostly brown, but were irredescent.......in the late 1930's. And certainly Proskey allowed the use of ammonia hydroxide as a cleaning agent near the storage of the coins. The envelopes may have had an effect if they had sulfur, but the sulfur would have created different colors.
So Stewart Blay is correct when he asserts that these coins have been chemically altered to create the color. But it was not done by coin doctors to ruin his business. Most of these coins were blue before Stewart was born. And I will reassert my concern that most old copper that grades as RD has been dipped to maintain the original color. Coins fresh out of the mint do not have original skin. Original skin is the first layer of tarnish that the coin naturally attains. Blue IHC's do have original skin. RD IHC's have been "conserved" with chemicals to eliminate the tarnish. What is Original about that?
@jtlee321 said:
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.
The coin looks to have been cleaned at some point and looks unnatural to me regardless of the MS70 debate.
@dcarr said:
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.
@OldIndianNutKase said:
Let us get back to the OP's original question, How did this coin turn blue naturally?
And the answer is that it was exposed toAmmonium Hydroxide Vapor. This color did not come from sulfur in paper envelopes as has been commonly believed. Nor have these coins been dipped to create this color artificially... Before the creation of Mr. Clean and 409 in the 1960's, the most common cleaning agent in houses and commercial buildings was ammonia in a water solution, ammonium hydroxide.
OINK
I have a hard time believing that most blue copper coins have come in contact with household cleaning vapors let alone sufficient quantities to cause significant color changes like the coins in this thread. Any ammonia vapor would be small and seemingly too dilute to do much of anything.
@dcarr said:
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.
Wouldn't that be called doctored/manufactured?
Yes.
I think that you are on a witch hunt. JT Lee described his photography angles that show the coin as brown and with a different angle the colors show. I previously posted the remarkably "blue" IHC PR:
This what this coin looks like in the slab:
It is a BN coin with irredescent toning as has been historically described by Rick Snow since about 1930. Blay want to whine about "blue" coins are all doctored. These coins were blue before he was born. The blue is Original Skin caused by exposure to ammonium hydroxide vapor ( basically NH3 vapor) which was to predomnant household cleaning agent prior to about 1960. The 1885 IHC PR posted above was toned very uniformly by vapor, and certainly not by MS70 which would be applied in liquid form and with a brush or Q-Tip. The skin on the 1885 is totally Original as it was the first layer of tarnish on the coin. RD IHC's that have Original Surface are a very large leap of faith as copper is much too reactive to be perfectly RD after 100+ years.
I think that you are on a witch hunt. JT Lee described his photography angles that show the coin as brown and with a different angle the colors show. I previously posted the remarkably "blue" IHC PR...
It is a BN coin with irredescent toning as has been historically described by Rick Snow since about 1930. Blay want to whine about "blue" coins are all doctored. These coins were blue before he was born. The blue is Original Skin caused by exposure to ammonium hydroxide vapor ( basically NH3 vapor) which was to predomnant household cleaning agent prior to about 1960. The 1885 IHC PR posted above was toned very uniformly by vapor, and certainly not by MS70 which would be applied in liquid form and with a brush or Q-Tip. The skin on the 1885 is totally Original as it was the first layer of tarnish on the coin. RD IHC's that have Original Surface are a very large leap of faith as copper is much too reactive to be perfectly RD after 100+ years.
OINK
I'm not on a witch hunt at all, nor am I making broad proclamations that all or even most blue copper either is or is not AT/chemically treated. I would like to see the answer resolved scientifically to provide a definitive answer. I simply find your NH4OH argument unpersuasive for the reasons cited in my other post (largely based on dilution and ammonia fume availability/exposure). Regardless of whether natural blue copper exists, the IHC from JTL has surfaces that look unnatural and the color also looks unnatural to me.
@OldIndianNutKase said:
Let us get back to the OP's original question, How did this coin turn blue naturally?
And the answer is that it was exposed toAmmonium Hydroxide Vapor. This color did not come from sulfur in paper envelopes as has been commonly believed. Nor have these coins been dipped to create this color artificially... Before the creation of Mr. Clean and 409 in the 1960's, the most common cleaning agent in houses and commercial buildings was ammonia in a water solution, ammonium hydroxide.
OINK
I have a hard time believing that most blue copper coins have come in contact with household cleaning vapors let alone sufficient quantities to cause significant color changes like the coins in this thread. Any ammonia vapor would be small and seemingly too dilute to do much of anything.
These coins were exposed to NH3 vapor not for one instance, but in very low doses over a period of at least 50 years. I know of few other chemicals that are as reactive with copper as is ammonia. My company builds ammonia refrigeration plants. Copper components cannot be used with NH3 because ot will completely destroy copper. It does not take much to change the color of copper with NH3 vapor. And the reaction will make the copper blue.
Seemingly not too hard to do. I will have to try this on an actual IHC proof to see if the effect can be reproduced quickly, or if it will take very low doses applied over a long period of time.
@OldIndianNutKase said:
Let us get back to the OP's original question, How did this coin turn blue naturally?
And the answer is that it was exposed toAmmonium Hydroxide Vapor. This color did not come from sulfur in paper envelopes as has been commonly believed. Nor have these coins been dipped to create this color artificially... Before the creation of Mr. Clean and 409 in the 1960's, the most common cleaning agent in houses and commercial buildings was ammonia in a water solution, ammonium hydroxide.
OINK
I have a hard time believing that most blue copper coins have come in contact with household cleaning vapors let alone sufficient quantities to cause significant color changes like the coins in this thread. Any ammonia vapor would be small and seemingly too dilute to do much of anything.
These coins were exposed to NH3 vapor not for one instance, but in very low doses over a period of at least 50 years. I know of few other chemicals that are as reactive with copper as is ammonia. My company builds ammonia refrigeration plants. Copper components cannot be used with NH3 because ot will completely destroy copper. It does not take much to change the color of copper with NH3 vapor. And the reaction will make the copper blue.
It sounds like you have the resources to test your theory. Toning will depend on time and the amount of NH3 exposure. Due to the high reactivity, increasing the amount/exposure should compensate for the shorter time frame. Expose red copper to varying amounts of NH3 over varying time periods in a controlled environment and analyze. Compare the amount of NH3 used to impart a blue color to known or estimated atmospheric NH3 levels.
I say this not as a smart alec, but as someone who cares about arriving at scientifically sound conclusions. If you are correct that atmospheric NH3 is the culprit, this would go beyond household cleaners but also create new questions.
"I say this not as a smart alec, but as someone who cares about arriving at scientifically sound conclusions. If you are correct that atmospheric NH3 is the culprit, this would go beyond household cleaners but also create new questions."
My premise is that ammonia was the predominant household cleaning agent before 1960 +/-. I am old enough to remember my mother using it and the whole house would smell of ammonia for at least an hour or so. Products like Mr. Clean and 409 were developed to eliminate the ammonia smell issue. And they to this day do not clean as well. But ammonia was all people used for hundreds of years. Coins were not in slabs, they were in paper envelopes or maybe just a coin cabinet. They were exposed to very low doses on about a weekly basis for many years. Hard to duplicate that, but identification as NH3 as the principal bluing agent would add a lot to our understanding of copper toning.
On another note, Bob Simpson's collection of US Pattern coins was auctioned by Legend in late January this year at the PCGS Members Show in Las Vegas. Most ALL of those coins were colorfully toned as many were struck in copper or brass. You certainly cannot believe that somebody AT'd all of those unique coins?
On another note, Bob Simpson's collection of US Pattern coins was auctioned by Legend in late January this year at the PCGS Members Show in Las Vegas. Most ALL of those coins were colorfully toned as many were struck in copper or brass. You certainly cannot believe that somebody AT'd all of those unique coins?
This is a strawman argument. I never said the pieces were AT nor did I reach any conclusion about whether NT blue copper is plentiful or whether it exists at all. My comments in this thread have mostly centered around disagreement with your theory that atmospheric levels of NH3 exist at levels sufficient to cause the supply of blue copper and specifically your argument that fumes from household cleaners are the culprit.
Edited to add: Looking back, I did call out one raw IHC here as AT. I stand by that conclusion. That coin is not on the same level as the other coins in this thread or the Simpson coins in my opinion. No offense meant to any poster.
Check out this website which lists homemade recipes for adding a patina to bronze and copper artifacts. Interestingly, NH4OH (the ingredient you cited) is listed as a formula to create a purple to light green patina. An NH4Cl compound could create a blue patina; however, other sites where I have seen ammonia based compounds used appear to produce a thick, opaque color (most result in the formation of a crystalline structure). There is a formula for a transparent blue patina (as one would expect on a coin) involving the use of a sulfur-based compound.
as more thought is added to my inquiry by different members I find myself thinking in different directions and trying to keep an open mind. in one hand I have what my experience and observation has taught me, in the other I have what conclusions members have drawn from their experience. balanced on my head I have chemical equations and science I hadn't thought about before. it is a peculiar conundrum.
if I ponder and understand Rick Snow's assertion, it is that the "color" we see on these coins has formed naturally but has been obscured by debris on the coin surface. when that debris is removed we see the color. the twist with this line of thought seems to be the MS70:
--- is it the lone component that can effectively remove the debris on some coins so we see the color??
--- is it reacting with the coin surface to produce the color??
I think that is the debate distilled down to its simplest form.
some of what has been mentioned vis-a-vis the chemical discussion has me wondering --- it seems to be human nature for coin collectors to mess with their coins in order to improve there appearance, not the opposite. we need to be instructed to NOT CLEAN OR OTHERWISE ALTER a coin's appearance. it isn't a leap to assume that the collectors of the past Centuries thought the same, that they sought ways to improve how their coins looked. I have 2-3 old school publications from the 1940-1960 era relating to Coin Chemistry, Preservation and for lack of a better term, Doctoring.
I would ask the obvious questions --- why do we always assume that the coins we see are original and have never had anything non-destructive done to them?? why do we always assume that no collector(s) in the past ever tried to enhance the appearance of their coins?? why do we always assume that the mentality of the Modern collector in regards to these matters is something new, not some innate human quality??
I wonder what the mentality is that wants exotic colors, rather than subtle or natural ones? 50 years ago, 100 years ago did collectors want colored coins?
And you wonder what the liklihood is that the coins won't turn in the holders once subjected to treatment? The grading services only guarantee these for a limited time, maybe they need to be kept in a climate controlled environment. There was the old MS70 and the newer one, most people I've talked to liked the old one.
The Jenks collection of proof coinage did not have blue proof Indian cents. It was one of the finest collection of proof coins . Remember the 1909 VDB that graded PR 67 R/B + ? There was no blue on that coin
If you like Larry Shepards assortment of colorfully psychedelic Indian cents then enjoy them.
OldIndianNut Case - You absolutely do not know what original skin is on a coin.It is not tarnish. It is luster.mint bloom.
When I exhibited my collection of copper in 2008 in Baltimore there were no blue coins .
How many dipped coins did anyone see ?
There was an 1807Large Centgraded Ms 66 red and it was original.
There was a 1795 Talbot Alum and Lee almost full red that was not dipped.
There was an 1856 Flying Eagle Paytern that was 85% red and undipped
My collection of Indian cents were at least 98 % original undipped
I have bought proof copper coins out of Bowers and Merena and Stacks auctions that were
Taken out of mint issued tissue paper. I know original color
I miss old forum member Shylock, he had a photographic memory for IHC's and kept very, very extensive picture files. that was quite helpful here at uncovering before/after IHC's. can anyone else provide some pictures of the coins doctored by GMarguli and his partner??
If some copper coins turn blue and the color is obscured by dirt/oxide and the color comes forth by using MS70 but later disappears or dissipates or is canceled out by an application of oil does this indicate most blue coins have had MS70 or some other cleaner applied?
"May the silver waves that bear you heavenward be filled with love’s whisperings"
"A dog breaks your heart only one time and that is when they pass on". Unknown
MS70 is a detergent. It was originally designed as an industrial golf ball cleaner at driving ranges. The solution is designed to remove dirt from range balls. Not sure how much it is still used today . .
@OldIndianNutKase said:
Let us get back to the OP's original question, How did this coin turn blue naturally?
And the answer is that it was exposed toAmmonium Hydroxide Vapor. This color did not come from sulfur in paper envelopes as has been commonly believed. Nor have these coins been dipped to create this color artificially. When I Googled copper compound colors, and how to create them, bluish and redish patination have a common ingredient in the agent used to create this effect........ammonia hydroxide. Ammonia hydroxide is ammonia gas in water solution. It will exist as liquid and vapor in this form, but ammonia gas only exists as a liquid at high pressures. Soooo, how did these coins become "doctored" with ammonia vapor?
Before the creation of Mr. Clean and 409 in the 1960's, the most common cleaning agent in houses and commercial buildings was ammonia in a water solution, ammonium hydroxide. I remember my mother cleaning the house with ammonia (as it was called) and the house would smell of ammonia for a few hours. And this would happen at least once a week. In my business we build ammonia refrigeration plants. Copper is so reactive with ammonia that you cannot use copper in contact with pure ammonia gas. The copper will just corrode away. I even found a method to create blue copper by suspending a copper sample above a paper towel saturated with ammonia hydroxide in a closed container. Expect results in 2-3 minutes to 2-3 hours depending on how much blue you desire. I will try this on some low value coins.
Rick Snow's research provides great historical perspective to this issue. It was found that the Proskey hoard of proof Indian Cents were mostly brown, but were irredescent.......in the late 1930's. And certainly Proskey allowed the use of ammonia hydroxide as a cleaning agent near the storage of the coins. The envelopes may have had an effect if they had sulfur, but the sulfur would have created different colors.
So Stewart Blay is correct when he asserts that these coins have been chemically altered to create the color. But it was not done by coin doctors to ruin his business. Most of these coins were blue before Stewart was born. And I will reassert my concern that most old copper that grades as RD has been dipped to maintain the original color. Coins fresh out of the mint do not have original skin. Original skin is the first layer of tarnish that the coin naturally attains. Blue IHC's do have original skin. RD IHC's have been "conserved" with chemicals to eliminate the tarnish. What is Original about that?
OINK
Seems like a good experiment to try by suspending a copper coin above a ammonia hydroxide saturated paper towel in a closed container. Please post your images when you try it.
The toned proof Lincoln and IHC look natural to me; maybe proof copper coins can tone blue (although of course this doesn't mean all proof blue-toned copper coins are natural) but business strikes cannot?
IMO natural in that AT is rampant. Chlorides and chlorites as well as allied oxidants can also impart bluish tone, so not just ammonia compounds.
I really do not see how old exposure to cleaning solutions and solvents, even if true or proposed as the cause of blue and/or purple toning can now be written off now as NT!
Love that Milled British (1830-1960) Well, just Love coins, period.
Coins can be filthy and carry germs. No reason not to consider a super light bath just to remove toxins as being a bad thing. The coin (and you) will live longer. Careful though! Too much of a good thing and copper turns pinkish.
CameoNut: I have a hard time believing that most blue copper coins have come in contact with household cleaning vapors let alone sufficient quantities to cause significant color changes like the coins in this thread.
Yes, this theory is flawed.
Old Indian NutKase: And the answer is that it was exposed to Ammonium Hydroxide Vapor.
Using some kind of ammonia dominated compound, not necessarily a vapor, is one way that coin doctors and others deliberately change the color of coins. It is not the only way that blue color may be imparted on copper. I have talked to enough coin doctors and to graders who try hard to detect doctoring to know for sure that there are many ways to doctor copper coins. Ammonia is part of some techniques and not part of the others. Copper sulphate is blue, too.
Old Indian NutKase: So Stewart Blay is correct when he asserts that these coins have been chemically altered to create the color. But it was not done by coin doctors to ruin his business. Most of these coins were blue before Stewart was born.
No, fifteen years ago, there were very few such blue toned copper coins in PCGS holders. Quantities of recently blue-toned copper coins that have been PCGS graded have increased a great deal in recent years. It is a current issue!
Old Indian NutKase: I think that you are on a witch hunt.
Since most us have not seen the coin pictured in the original post, it would make sense for us to stop talking about photography and talk about the many blue-toned copper coins that have received high grades from PCGS and ATS in recent years. Stewart seems to be arguing that all of these are the work of coin doctors. I am agreeing in large part. Probably, most of them are AT. Without seeing all of them, I will not comment on all of them. There are some blue hues that naturally occur on copper coins, as there are some pink shades that are NT on silver. In a majority of cases (far from always), blue on copper and pink on silver are deliberate AT.
In any event, taking a brown coin and turning it blue and then sending it to PCGS to be assigned a numerical grade is not an ethical activity, in my opinion. Such behavior is harmful to the coin community.
Stewart Blay: The Jenks collection of proof coinage did not have blue proof Indian cents. It was one of the finest collection of proof coins .
This is an important point. John Story Jenks had an amazing run of late 19th and early 20th century Proof sets that were purchased in 1921 by one buyer and then stored at a coin store in NY for many decades before being handled by Eric Streiner circa 1990. These were naturally toned. I saw many of them, too. I looked at them carefully. If Stewart would acknowledge that I am an expert grader too, and stop making nasty remarks, we could further help people understand the difference between NT and AT.
Stewart Blay: There was an 1807 Large Centgraded Ms 66 red and it was original.
Also, I mentioned Jenks in my most recent article. If people learned more about the great collections of the past, they would be better suited to detect AT in the present:
Wow. I've read through this "chemistry" discussion, and can't resist making a few polite comments.
Copper is found in nature both in its elemental metallic form and in a number of common minerals or salts.
Many, but not all, copper salts are blue to blue green in color. These include common copper salts such as the carbonate, sulfate, hydroxide, nitrate, and both chlorides.
Copper is a reactive element, and forms a protective patina with outdoor exposure. The exact composition can vary, but consists of a mixture of salts including copper carbonate, copper chloride, and copper sulfate.
Common brown patina of coins is due to a mixture of copper oxides which are actually either red or black. Such oxides are very stable, and generally preclude formation of other copper salts in the absence of strong chemical exposure.
Exposure to other substances such as moisture, sweat, air, etc. can result in formation of other copper salts which will alter coin appearance either positively or negatively. Formation of blue / green compounds is very common with copper.
Coin collectors in general didn't do well in chemistry class in school. There are exceptions though.
Comments
with regard to copper and color, is blue really a stable color for copper in the natural world??
Probably. There is no formula on the bottle so all I could do is a pH test.
Best, SH
I think that would depend on what the definition of 'stable' is. Years, decades, longer? Would also depend on what environment the copper is in, perhaps in a slab with limited air exchange it is more stable, but Cu is a very reactive metal.
Best, SH
ronyhaski, you posted "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."
On what evidence is this based? Published research? Your own experiments? I don't intend to sound like I am challenging you, but when one makes an authoritative sounding statement like this, I think there should be a firm substrate of facts. Your extended post clearly shows an intense interest in this area.
thanks,
Kaz
?"Copper coins do not, as a rule, only take on different shades of brown...." I don't agree, they do in fact generally DO turn different shades of brown eventually and that other colors or preservation of original red are more the exception. How many bags of wheaties does it take to prove that point?
Original "skin" is IMO a poor term as it is but the surface metal alloy that certainly can be variably oxidized in such environments; there is nothing per se special about this so-called skin. I do agree, and do not attempt to venture an explanation that it seems previously somewhat stable surfaces that are once again destabilized by dips or oxidants do seem to retone in the manner described.
Also, I wanted to revisit the "oxidation" of MS 70. I guess that we did not learn in chemistry that this was the case. Base pH yields a dearth of protons/ + charges in solution, a tendency to REDUCE therefore.
I am not understanding how multiple previous tests reported in many places did demonstrate purple/bluish tone imparted to copper coins after MS70 treatments, and now the claims are being forwarded that this does not occur. I have not purposely gone out to test this, but will note I have had one cent pieces turn what is apparently purple and have the same thing noted with British farthings, both of the pre-1860 copper type, and the later "bunhead" bronze alloy pieces.
Well, just Love coins, period.
There is no formula on the bottle so all I could do is a pH test.
you can do a search on Google and find the ingredients and an explanation of the formulation, along with other specifics about the product.
from what I was able to find, it contains sodium gluconate (chelating agent); a sulfonate surfactant; and good ol' lye.
So many experts, so little knowledge. There are so many variables it is ignorant to generalize.
What about wood grain toning on 1909 Lincoln cents ?
Has anyone ever seen a blue 1909 Lincoln cent ?
S mint Lincoln cents in the 1920's will most likely be softly struck and appear brassy in mint state.when well struck they appear cherry red.
None of these dates will ever appear blue unless chemically altered.
Save the blue for my mushrooms and the red-brown for my cents.
I don't understand how anybody would want anything but this on their copper cent pieces. It boggles my mind.
Video killed the radio star and coin doctors killed the toned coin market.
" There are so many variables it is ignorant to generalize."
"None of these dates will ever appear blue unless chemically altered."
Correct me if wrong, but I perceive a conflict.
Sorry to say the 2014 version looks like it has been attacked. From your photos the coin in the before photo looks much nicer. Makes me wonder how many times a coin could be "touched up" with MS70 before the blue stops showing up.
"A dog breaks your heart only one time and that is when they pass on". Unknown
The before photo shows a heavily patinated copper half cent. What does not show up well in the images is that this coin was wiped and parallel hairlines are present on both obverse and reverse - hence a no grade with PCGS and a details grade with ANACS prior to me cracking it for the test. But like all coins, it probably went through many 'touch ups' before it got to me, and that might also dictate how MS70 reacted with it. HST, the coin in hand today after removing the patina with MS70, and after the blue disappeared, is tremendously nice, except for the parallel hairlines...
Best, SH
What about wood grain toning? Whether it results from improper planchet alloy, contaminants on the rollers, whatever, how does that factor into natural or fake blue toning? Here is a coin with wood grain toning, with blue toning in it.
YES, you haven't? Do you believe that these are all chemically altered?
Here is a 1926-S with blue toning in it. Do you believe that this coin has been chemically altered? ( Full disclosure: I own this coin.)
Ronyahski - First, you need to understand what is wood grain toning
Second - Every coin you displayed including your 1926 s has been chemically
Altered.
Azurescens - nice coin ,gorgeous color and totally original
Agreed
Well, just Love coins, period.
Afford:
CoinKat:
Whether the pictured coin is truly blue is beside that the point of this thread, as I understand it.
I have seen many 99+% copper and 95% copper coins with blue tones, sometimes strange deep blue tints that seem encompassing. In many cases, the blue tones are the result of deliberate artificial toning. On early copper coins, blue is sometimes a byproduct of treatments of corrosion, with oils or other substances. On occasion, natural blue tones may occur. Natural blue tones on small cents are somewhat uncommon and many blue tones, particularly on Indian cents and Lincoln cents, are AT.
Rick:
I disagree. There is a chemical tendency for copper coins to turn brown. They do not have to be in an envelope or exposed to much sulphur for this to occur. There are countervailing tendencies as well, though the tendency for copper to turn brown and eventually green (not blue) is powerful. Almost all coins are toning every day, really every slice of time. For most coins, the process is so slow that toning is not noticeable for many years or decades.
Rick:
No, coin doctors frequently add blue color to copper coins. Others do as well, through treatments for corrosion and/or with substances that are believed by the users to be harmless.
Keets:
Although I have never used this "MS-70" product myself. Keets' remarks are consistent with what I have been told by sources that are usually reliable.
Stewart:
Coin doctoring is a danger to all markets for rare or scarce coins.
The Specter of Coin Doctoring and The Survival of Great Coins
Let us get back to the OP's original question, How did this coin turn blue naturally?
And the answer is that it was exposed to Ammonium Hydroxide Vapor. This color did not come from sulfur in paper envelopes as has been commonly believed. Nor have these coins been dipped to create this color artificially. When I Googled copper compound colors, and how to create them, bluish and redish patination have a common ingredient in the agent used to create this effect........ammonia hydroxide. Ammonia hydroxide is ammonia gas in water solution. It will exist as liquid and vapor in this form, but ammonia gas only exists as a liquid at high pressures. Soooo, how did these coins become "doctored" with ammonia vapor?
Before the creation of Mr. Clean and 409 in the 1960's, the most common cleaning agent in houses and commercial buildings was ammonia in a water solution, ammonium hydroxide. I remember my mother cleaning the house with ammonia (as it was called) and the house would smell of ammonia for a few hours. And this would happen at least once a week. In my business we build ammonia refrigeration plants. Copper is so reactive with ammonia that you cannot use copper in contact with pure ammonia gas. The copper will just corrode away. I even found a method to create blue copper by suspending a copper sample above a paper towel saturated with ammonia hydroxide in a closed container. Expect results in 2-3 minutes to 2-3 hours depending on how much blue you desire. I will try this on some low value coins.
Rick Snow's research provides great historical perspective to this issue. It was found that the Proskey hoard of proof Indian Cents were mostly brown, but were irredescent.......in the late 1930's. And certainly Proskey allowed the use of ammonia hydroxide as a cleaning agent near the storage of the coins. The envelopes may have had an effect if they had sulfur, but the sulfur would have created different colors.
So Stewart Blay is correct when he asserts that these coins have been chemically altered to create the color. But it was not done by coin doctors to ruin his business. Most of these coins were blue before Stewart was born. And I will reassert my concern that most old copper that grades as RD has been dipped to maintain the original color. Coins fresh out of the mint do not have original skin. Original skin is the first layer of tarnish that the coin naturally attains. Blue IHC's do have original skin. RD IHC's have been "conserved" with chemicals to eliminate the tarnish. What is Original about that?
OINK
The coin looks to have been cleaned at some point and looks unnatural to me regardless of the MS70 debate.
Yes.
I have a hard time believing that most blue copper coins have come in contact with household cleaning vapors let alone sufficient quantities to cause significant color changes like the coins in this thread. Any ammonia vapor would be small and seemingly too dilute to do much of anything.
I think that you are on a witch hunt. JT Lee described his photography angles that show the coin as brown and with a different angle the colors show. I previously posted the remarkably "blue" IHC PR:
This what this coin looks like in the slab:
It is a BN coin with irredescent toning as has been historically described by Rick Snow since about 1930. Blay want to whine about "blue" coins are all doctored. These coins were blue before he was born. The blue is Original Skin caused by exposure to ammonium hydroxide vapor ( basically NH3 vapor) which was to predomnant household cleaning agent prior to about 1960. The 1885 IHC PR posted above was toned very uniformly by vapor, and certainly not by MS70 which would be applied in liquid form and with a brush or Q-Tip. The skin on the 1885 is totally Original as it was the first layer of tarnish on the coin. RD IHC's that have Original Surface are a very large leap of faith as copper is much too reactive to be perfectly RD after 100+ years.
OINK
I'm not on a witch hunt at all, nor am I making broad proclamations that all or even most blue copper either is or is not AT/chemically treated. I would like to see the answer resolved scientifically to provide a definitive answer. I simply find your NH4OH argument unpersuasive for the reasons cited in my other post (largely based on dilution and ammonia fume availability/exposure). Regardless of whether natural blue copper exists, the IHC from JTL has surfaces that look unnatural and the color also looks unnatural to me.
These coins were exposed to NH3 vapor not for one instance, but in very low doses over a period of at least 50 years. I know of few other chemicals that are as reactive with copper as is ammonia. My company builds ammonia refrigeration plants. Copper components cannot be used with NH3 because ot will completely destroy copper. It does not take much to change the color of copper with NH3 vapor. And the reaction will make the copper blue.
A link to a process with NH3 that will turn copper blue:
http://www.instructables.com/id/Blue-Patina-on-Copper/
Seemingly not too hard to do. I will have to try this on an actual IHC proof to see if the effect can be reproduced quickly, or if it will take very low doses applied over a long period of time.
It sounds like you have the resources to test your theory. Toning will depend on time and the amount of NH3 exposure. Due to the high reactivity, increasing the amount/exposure should compensate for the shorter time frame. Expose red copper to varying amounts of NH3 over varying time periods in a controlled environment and analyze. Compare the amount of NH3 used to impart a blue color to known or estimated atmospheric NH3 levels.
I say this not as a smart alec, but as someone who cares about arriving at scientifically sound conclusions. If you are correct that atmospheric NH3 is the culprit, this would go beyond household cleaners but also create new questions.
"I say this not as a smart alec, but as someone who cares about arriving at scientifically sound conclusions. If you are correct that atmospheric NH3 is the culprit, this would go beyond household cleaners but also create new questions."
My premise is that ammonia was the predominant household cleaning agent before 1960 +/-. I am old enough to remember my mother using it and the whole house would smell of ammonia for at least an hour or so. Products like Mr. Clean and 409 were developed to eliminate the ammonia smell issue. And they to this day do not clean as well. But ammonia was all people used for hundreds of years. Coins were not in slabs, they were in paper envelopes or maybe just a coin cabinet. They were exposed to very low doses on about a weekly basis for many years. Hard to duplicate that, but identification as NH3 as the principal bluing agent would add a lot to our understanding of copper toning.
On another note, Bob Simpson's collection of US Pattern coins was auctioned by Legend in late January this year at the PCGS Members Show in Las Vegas. Most ALL of those coins were colorfully toned as many were struck in copper or brass. You certainly cannot believe that somebody AT'd all of those unique coins?
>
This is a strawman argument. I never said the pieces were AT nor did I reach any conclusion about whether NT blue copper is plentiful or whether it exists at all. My comments in this thread have mostly centered around disagreement with your theory that atmospheric levels of NH3 exist at levels sufficient to cause the supply of blue copper and specifically your argument that fumes from household cleaners are the culprit.
Edited to add: Looking back, I did call out one raw IHC here as AT. I stand by that conclusion. That coin is not on the same level as the other coins in this thread or the Simpson coins in my opinion. No offense meant to any poster.
@OldIndianNutKase
Check out this website which lists homemade recipes for adding a patina to bronze and copper artifacts. Interestingly, NH4OH (the ingredient you cited) is listed as a formula to create a purple to light green patina. An NH4Cl compound could create a blue patina; however, other sites where I have seen ammonia based compounds used appear to produce a thick, opaque color (most result in the formation of a crystalline structure). There is a formula for a transparent blue patina (as one would expect on a coin) involving the use of a sulfur-based compound.
https://www.sciencecompany.com/Patina-Formulas-for-Brass-Bronze-and-Copper.aspx#13
.
The Owner and all her previous owners listened to lot of Muddy Waters
Steve
as more thought is added to my inquiry by different members I find myself thinking in different directions and trying to keep an open mind. in one hand I have what my experience and observation has taught me, in the other I have what conclusions members have drawn from their experience. balanced on my head I have chemical equations and science I hadn't thought about before. it is a peculiar conundrum.
if I ponder and understand Rick Snow's assertion, it is that the "color" we see on these coins has formed naturally but has been obscured by debris on the coin surface. when that debris is removed we see the color. the twist with this line of thought seems to be the MS70:
--- is it the lone component that can effectively remove the debris on some coins so we see the color??
--- is it reacting with the coin surface to produce the color??
I think that is the debate distilled down to its simplest form.
some of what has been mentioned vis-a-vis the chemical discussion has me wondering --- it seems to be human nature for coin collectors to mess with their coins in order to improve there appearance, not the opposite. we need to be instructed to NOT CLEAN OR OTHERWISE ALTER a coin's appearance. it isn't a leap to assume that the collectors of the past Centuries thought the same, that they sought ways to improve how their coins looked. I have 2-3 old school publications from the 1940-1960 era relating to Coin Chemistry, Preservation and for lack of a better term, Doctoring.
I would ask the obvious questions --- why do we always assume that the coins we see are original and have never had anything non-destructive done to them?? why do we always assume that no collector(s) in the past ever tried to enhance the appearance of their coins?? why do we always assume that the mentality of the Modern collector in regards to these matters is something new, not some innate human quality??
I wonder what the mentality is that wants exotic colors, rather than subtle or natural ones? 50 years ago, 100 years ago did collectors want colored coins?
And you wonder what the liklihood is that the coins won't turn in the holders once subjected to treatment? The grading services only guarantee these for a limited time, maybe they need to be kept in a climate controlled environment. There was the old MS70 and the newer one, most people I've talked to liked the old one.
The Jenks collection of proof coinage did not have blue proof Indian cents. It was one of the finest collection of proof coins . Remember the 1909 VDB that graded PR 67 R/B + ? There was no blue on that coin
If you like Larry Shepards assortment of colorfully psychedelic Indian cents then enjoy them.
OldIndianNut Case - You absolutely do not know what original skin is on a coin.It is not tarnish. It is luster.mint bloom.
When I exhibited my collection of copper in 2008 in Baltimore there were no blue coins .
How many dipped coins did anyone see ?
There was an 1807Large Centgraded Ms 66 red and it was original.
There was a 1795 Talbot Alum and Lee almost full red that was not dipped.
There was an 1856 Flying Eagle Paytern that was 85% red and undipped
My collection of Indian cents were at least 98 % original undipped
I have bought proof copper coins out of Bowers and Merena and Stacks auctions that were
Taken out of mint issued tissue paper. I know original color
So OldIndianNutCase Oink Oink to you
I miss old forum member Shylock, he had a photographic memory for IHC's and kept very, very extensive picture files. that was quite helpful here at uncovering before/after IHC's. can anyone else provide some pictures of the coins doctored by GMarguli and his partner??
If some copper coins turn blue and the color is obscured by dirt/oxide and the color comes forth by using MS70 but later disappears or dissipates or is canceled out by an application of oil does this indicate most blue coins have had MS70 or some other cleaner applied?
"A dog breaks your heart only one time and that is when they pass on". Unknown
This one was mine. Pulled it from a dealer's binder as MS for $3... lol. PCGS PR67BN,
the explanation for those colors in that time period has been well documented, including the causes.
https://forums.collectors.com/discussion/976944/proof-indian-cent#latest
MS70 is a detergent. It was originally designed as an industrial golf ball cleaner at driving ranges. The solution is designed to remove dirt from range balls. Not sure how much it is still used today . .
Drunner
Seems like a good experiment to try by suspending a copper coin above a ammonia hydroxide saturated paper towel in a closed container. Please post your images when you try it.
Out of curiosity, is the number of blue coins increasing, stable or decreasing?
The toned proof Lincoln and IHC look natural to me; maybe proof copper coins can tone blue (although of course this doesn't mean all proof blue-toned copper coins are natural) but business strikes cannot?
Gobrecht's Engraved Mature Head Large Cent Model
https://www.instagram.com/rexrarities/?hl=en
IMO natural in that AT is rampant. Chlorides and chlorites as well as allied oxidants can also impart bluish tone, so not just ammonia compounds.
I really do not see how old exposure to cleaning solutions and solvents, even if true or proposed as the cause of blue and/or purple toning can now be written off now as NT!
Well, just Love coins, period.
Coins can be filthy and carry germs. No reason not to consider a super light bath just to remove toxins as being a bad thing. The coin (and you) will live longer. Careful though! Too much of a good thing and copper turns pinkish.
I think I owed it or one like it before selling it to a forum member. Did you sell your coin?
The Sun and the Blue-toned rooster
Since there are way too many posting on various tangents, I decided to start a new thread to share my findings.
Yes, I sold it to someone who sold it on eBay for about double the price I sold it to him for. My knowledge of it ends there.
CameoNut:
Yes, this theory is flawed.
Old Indian NutKase:
Using some kind of ammonia dominated compound, not necessarily a vapor, is one way that coin doctors and others deliberately change the color of coins. It is not the only way that blue color may be imparted on copper. I have talked to enough coin doctors and to graders who try hard to detect doctoring to know for sure that there are many ways to doctor copper coins. Ammonia is part of some techniques and not part of the others. Copper sulphate is blue, too.
Old Indian NutKase:
No, fifteen years ago, there were very few such blue toned copper coins in PCGS holders. Quantities of recently blue-toned copper coins that have been PCGS graded have increased a great deal in recent years. It is a current issue!
Old Indian NutKase:
Since most us have not seen the coin pictured in the original post, it would make sense for us to stop talking about photography and talk about the many blue-toned copper coins that have received high grades from PCGS and ATS in recent years. Stewart seems to be arguing that all of these are the work of coin doctors. I am agreeing in large part. Probably, most of them are AT. Without seeing all of them, I will not comment on all of them. There are some blue hues that naturally occur on copper coins, as there are some pink shades that are NT on silver. In a majority of cases (far from always), blue on copper and pink on silver are deliberate AT.
In any event, taking a brown coin and turning it blue and then sending it to PCGS to be assigned a numerical grade is not an ethical activity, in my opinion. Such behavior is harmful to the coin community.
Stewart Blay:
This is an important point. John Story Jenks had an amazing run of late 19th and early 20th century Proof sets that were purchased in 1921 by one buyer and then stored at a coin store in NY for many decades before being handled by Eric Streiner circa 1990. These were naturally toned. I saw many of them, too. I looked at them carefully. If Stewart would acknowledge that I am an expert grader too, and stop making nasty remarks, we could further help people understand the difference between NT and AT.
Stewart Blay:
No kidding, I wrote an article about it!
Is the Naftzger-Blay 1807/6 the only Gem Quality & Full Red ‘Early Date’ Large Cent?
Also, I mentioned Jenks in my most recent article. If people learned more about the great collections of the past, they would be better suited to detect AT in the present:
The Marvelous Pogue Family Coin Collection, Part 22: Epic Sales in the Same League
Wow. I've read through this "chemistry" discussion, and can't resist making a few polite comments.