I would love to see some phase diagrams produced from early Lincolns and IHCs. This I old-fashioned physical chemistry/metallurgy, and academics aren't really interested in this sort of thing anymore.
Member: EAC, NBS, C4, CWTS, ANA
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
Cool! You will donate your coin (or buy one) for this effort, won't you? And I would be pleased to support you to the tune of $100--I'm a big spender--when you publish the results. I might even say nice things about the paper.
Member: EAC, NBS, C4, CWTS, ANA
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
@RogerB said:
RE: "What's the point. We know the metals that the Mint used to compose the alloy. When they did not mix properly, to exhibit a single uniform color, they each retained shades of their normal color as pure."
Actually, we don't "know" that. Where is the empirical data? Why speculate when the technology is available to collect data? (Color is unimportant; it is a by-product of chemical composition - and that is the fundamental question.)
LOL, yes we do: Lincoln cent composition (1909-1958)
@RogerB said:
RE: "What's the point. We know the metals that the Mint used to compose the alloy. When they did not mix properly, to exhibit a single uniform color, they each retained shades of their normal color as pure."
Actually, we don't "know" that. Where is the empirical data? Why speculate when the technology is available to collect data? (Color is unimportant; it is a by-product of chemical composition - and that is the fundamental question.)
LOL, yes we do: Lincoln cent composition (1909-1958)
.950 Copper
.050 Tin and Zinc
No. You are confusing the macro alloy with the micro-alloy on a coin's surface. The first is a bulk measurement (or actually an assumption). The second is the alleged segregation of the elements constituting the alloy into patterns that oxidize differently. This segregation is supposed to produce the "wood grain" effect.
(PS: The proportions of tin, zinc and copper varied somewhat. After mid-Spring 1942, there was almost no tin.)
@RogerB said:
RE: "What's the point. We know the metals that the Mint used to compose the alloy. When they did not mix properly, to exhibit a single uniform color, they each retained shades of their normal color as pure."
Actually, we don't "know" that. Where is the empirical data? Why speculate when the technology is available to collect data? (Color is unimportant; it is a by-product of chemical composition - and that is the fundamental question.)
LOL, yes we do: Lincoln cent composition (1909-1958)
.950 Copper
.050 Tin and Zinc
I think Roger's point is that there could be an uneven distribution of metals. Personally, I would be surprised, but stranger things have happened.
hemical composition - and that is the fundamental question.)
LOL, yes we do: Lincoln cent composition (1909-1958)
.950 Copper
.050 Tin and Zinc
No. You are confusing the macro alloy with the micro-alloy on a coin's surface. The first is a bulk measurement (or actually an assumption). The second is the alleged segregation of the elements constituting the alloy into patterns that oxidize differently. This segregation is supposed to produce the "wood grain" effect.
(PS: The proportions of tin, zinc and copper varied somewhat. After mid-Spring 1942, there was almost no tin.)
This is interesting. There was no tin. Was there more zinc, more copper or both?
@RogerB said:
RE: "What's the point. We know the metals that the Mint used to compose the alloy. When they did not mix properly, to exhibit a single uniform color, they each retained shades of their normal color as pure."
Actually, we don't "know" that. Where is the empirical data? Why speculate when the technology is available to collect data? (Color is unimportant; it is a by-product of chemical composition - and that is the fundamental question.)
LOL, yes we do: Lincoln cent composition (1909-1958)
.950 Copper
.050 Tin and Zinc
No. You are confusing the macro alloy with the micro-alloy on a coin's surface. The first is a bulk measurement (or actually an assumption). The second is the alleged segregation of the elements constituting the alloy into patterns that oxidize differently. This segregation is supposed to produce the "wood grain" effect.
(PS: The proportions of tin, zinc and copper varied somewhat. After mid-Spring 1942, there was almost no tin.)
All you have posted is that Tin is no longer used. That makes the composition of the streaks on those dates even easier to determine.
The streaks on these coins usually goes deeper than the surface. Decades ago we proved it to ourselves. Unfortunately, a circulated Lincoln "Woodie" was lost to posterity.
@Sonorandesertrat said:
I'm reporting you to the ASPCC (American Society for the Prevention of Cruelty to Coins).
Go ahead, nothing will happen to me. I'm a charter board member of the CDOA (Coin Dippers of America). Thus, I have been given dispensation long ago for any coins in my care that I may destroy.
I did about 45 years ago, after I destroyed a gem 1918 Standing Liberty quarter---given to me by my grandmother---by overdipping. I totally stripped it, leaving no hit of luster left. Haven't touched the stuff since.
Member: EAC, NBS, C4, CWTS, ANA
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
@RogerB said:
RE: "What's the point. We know the metals that the Mint used to compose the alloy. When they did not mix properly, to exhibit a single uniform color, they each retained shades of their normal color as pure."
Actually, we don't "know" that. Where is the empirical data? Why speculate when the technology is available to collect data? (Color is unimportant; it is a by-product of chemical composition - and that is the fundamental question.)
LOL, yes we do: Lincoln cent composition (1909-1958)
.950 Copper
.050 Tin and Zinc
No. You are confusing the macro alloy with the micro-alloy on a coin's surface. The first is a bulk measurement (or actually an assumption). The second is the alleged segregation of the elements constituting the alloy into patterns that oxidize differently. This segregation is supposed to produce the "wood grain" effect.
(PS: The proportions of tin, zinc and copper varied somewhat. After mid-Spring 1942, there was almost no tin.)
All you have posted is that Tin is no longer used. That makes the composition of the streaks on those dates even easier to determine.
The streaks on these coins usually goes deeper than the surface. Decades ago we proved it to ourselves. Unfortunately, a circulated Lincoln "Woodie" was lost to posterity.
This is doubly interesting. How deep did it go? Oxidation [with or without actual oxygen] should not happen below the surface unless there is a contaminant in the melt. So, if the woodsie Lincoln didn't leave the mint already grainy and the streaks run deep, it argues for some kind of foreign substance. If the woodsie Lincoln left the mint already grainy, wouldn't someone have noticed?
Look in the thread. Mint Red Lincoln's exist with bright brass streaks - as struck. The colors are not due to the environment, foreign substances, or oxidation. Oxidation only changes the colors.
@Insider2 said:
Look in the thread. Mint Red Lincoln's exist with bright brass streaks - as struck. The colors are not due to the environment, foreign substances, or oxidation. Oxidation only changes the colors.
Even greater reason to know the composition of "streaks." We don't have to depend on guesses and arcane assumptions. I do not understand the resistance to obtaining objective data; is it to use the available supply of emotional excuses, or to protect the "received ignorance" of the past, or something else ?
@Insider2 said:
Look in the thread. Mint Red Lincoln's exist with bright brass streaks - as struck. The colors are not due to the environment, foreign substances, or oxidation. Oxidation only changes the colors.
Well then, I'm with Roger. If there are bright brass streaks as struck, those streaks would have to have a composition difference. That composition difference could be an alloy difference, a foreign substance in the mix, oxidation or some other chemical process.
"Oxidation", "sulfurization" and other chemical process can happen with aging but they are NOT strictly defined by aging.
What is the resistance to chemical analysis of the streaks? XRD/XRF is much less invasive than whatever you did to the woodsie Lincoln back in the day.
Wood Grain effect refers to a specific type of toning. To my knowledge
Copper coins were never struck with wood grain toning. . It was developed
later.
The earliest examples of wood grain
Toning, that I have seen were on 1864
Bronze Indian cents. The most common copper coins with wood grain toning
are 1909 Lincoln cents.
The greatest challenge for TPG
Is determining whether the coin should be graded red or red/brown. I can state
about an 1872 Indian cent with totally obvious wood grain effect toning
graded as ms 66 r/b. It was sold for
$ 10,000 by Angel Dees to an upgrader
who got a grade of ms 66 red from
PCGS. The coin was immediately
sold to an active set registry participant
for $ 60,000. To make the story short,
PCGS wound up buying the coin back
and down graded it to 66 r/b.
Many people in this thread are confusing streaky toning as wood grain.
It is not toning with a wood grain effect
Orange peel has to do with the skin on copper and gold coins.
Also streakiness due to chemically
altered coins has nothing to do with
Wood grain effect toning. Wood grain effect toning is a completely natural
Occurance.
Lastly to answers Rogers question
If a metallurgical analysis has ever been done on a wood grained copper coin, not
to my knowledge.
All metals handled by our mints were subject to possible contamination during handling. The most commonly discussed was "fire scale" which was often seen in copper melts and found in rolled out ingots. Metal flecks could get on strips and be rolled into the metal, ending up in struck coins. As explained by members in earlier posts, a tiny spot of inconsistency or surface contamination could be rolled out into oval streaks of indeterminate length. In short, a lot of things could produce wood grain appearance or alloy inconsistency leading to wood grain. But our bottom line is: What are the metallurgical differences that result in visible wood grain?
Anyone care to provide unslabbed coins for examination or professional lab services to do the tests?
@Insider2 said:
Look in the thread. Mint Red Lincoln's exist with bright brass streaks - as struck. The colors are not due to the environment, foreign substances, or oxidation. Oxidation only changes the colors.
Well then, I'm with Roger. If there are bright brass streaks as struck, those streaks would have to have a composition difference. That composition difference could be an alloy difference, a foreign substance in the mix, oxidation or some other chemical process.
"Oxidation", "sulfurization" and other chemical process can happen with aging but they are NOT strictly defined by aging.
What is the resistance to chemical analysis of the streaks? XRD/XRF is much less invasive than whatever you did to the woodsie Lincoln back in the day.
Duh, If I strike a coin on a .999 fine copper planchet it will be copper color. If I strike a coin on a planchet that is .999 fine copper on the right half and yellow brass on the other half I'm going to have a brilliant, frosty, original coin that is Red-pink on one side and yellow brass on the other AS STRUCK! Why complicate this with fantom impurities?
I have my eye on a wood-grained 1937 proof Buffalo nickel a friend has, PCGS PR65. It is marked as a Mirrored type, but it is a Satin. You either love it or hate it. It should lower the price due to appearance since most people want their proofs to be shiny and silvery, so I have to make him the proverbial "offer he can't refuse."
@EagleEye said:
The conclusion is that it is a property of the planchet, not the dies.
You see it on proof surfaces because the mirrors bring it out more. The "watery" surface is the grain size of the planchet metal and is not at all associated with the die.
This seems reasonable. Still need to read the article. Until then I did some research. This was posted from an old CU thread by another member:
Here’s Rick Snow’s (Eagle Eye Rare Coins - he specializes in Indian Head Cents) description as to how this occurs:
“After the dies are hubbed and the date is applied, the die is given multiple polishes with progressively finer and finer polish. The last polish given to the dies prior to being hardened gives the field a surface quite like a mirror. This is the deepest mirror attainable on the dies. When the die is hardened, the metal shrinks slightly creating a wavy effect on the polished surfaces. It looks somewhat like the surface of an orange. When you see orange peel on a proof issue you can be sure that it is one of the first examples struck from those dies. Later polishing to the already hardened dies will produce a flatter and shallower mirror."
"I would add that the dies don't have to be re-polished for this look to disappear - after the first few coins are struck, the metal to metal contact from the striking process has its own "polishing" effect and the waviness is minimized to the point where it is no longer visible on the struck proofs. (The same is true regarding the Cameo look of the first struck coins: after successive strikings, this cameo looks disappears, I believe due to the die wear that has initially "polished" away the "roughness" of the recessed devices of the coin die and perhaps also the filling of the recessed portions of the die with dirt, dust, oil, etc. that would tend to minimize the "cameo frost" on the struck coin."
So we probably will not disagree much except for the usage of the term "Orange Peel" and whether it results from the dies or the preparation of the planchet. I hope Mr. Carr can do an experiment for us.
This ripple effect is seen quite a bit on modern British proof coins, and I assumed it was due to their practice of hand-polishing their dies, rather than just lapping them on a table.
@thefinn said:
As a side note, not that many shell casings were used to make sense. It was a publicity stunt that was impractical.
Sorry, but your comment is completely false. If you pick up a copy of Pattern and Experimental Pieces of WW-II you can read about what was done to recycle brass military shell casings for US Mint coinage.
Short version: Brass shell cases, mostly 50 cal., were a problem for military training bases. Test batches were sent to the San Francisco Mint in 1943 but there was so much zinc volitization on melting, and the initial volume so great that the mints could not deal with the material that was shipped in boxcars. The military then shipped the cases to a contractor who melted the brass, cast it into usable bars, and sent it to US Mints. There, the bars were melted under makeshift collection hoods and sufficient pure copper was added to bring the alloy to 95% Cu, 4.9% Zn and a trace of tin. This was used for all one-cent coinage from 1944 through part of 1947 and was entirely satisfactory. Shell case cents have the same alloy as late 1942 cents, and the same basic alloy was used after the supply of shell cases was exhausted.
(Note: Brass shell cases cannot be recycled directly into new cases. The brass becomes brittle and cases made from it are not strong.)
@Insider2 said:
Look in the thread. Mint Red Lincoln's exist with bright brass streaks - as struck. The colors are not due to the environment, foreign substances, or oxidation. Oxidation only changes the colors.
Well then, I'm with Roger. If there are bright brass streaks as struck, those streaks would have to have a composition difference. That composition difference could be an alloy difference, a foreign substance in the mix, oxidation or some other chemical process.
"Oxidation", "sulfurization" and other chemical process can happen with aging but they are NOT strictly defined by aging.
What is the resistance to chemical analysis of the streaks? XRD/XRF is much less invasive than whatever you did to the woodsie Lincoln back in the day.
Duh, If I strike a coin on a .999 fine copper planchet it will be copper color. If I strike a coin on a planchet that is .999 fine copper on the right half and yellow brass on the other half I'm going to have a brilliant, frosty, original coin that is Red-pink on one side and yellow brass on the other AS STRUCK! Why complicate this with fantom impurities?
the impurity was only one possibility. You could verify the composition difference of the brass versus copper as well. You are ASSUMING that you know there is a specific alloy difference rather than simply verifying it with a simple test.
The proposition is very straight forward: Any change in color, even locally, must have a cause. Careful, professional XRF measurements can determine if alloy segregation or contamination are a cause.
Just took an image of a 1914-D 1c with a streak of silver. I've seen this several times before just as a silver coin with copper (much more common). I'll post it this week.
The only XRF analysis I have seen on shellcase Cents showed potassium and manganese in the brightly-colored areas. These elements are present in the primers on WW2 ammo, so this is the likely source for the "shellcase" color.
Here's a 46-S Shellcase Cent, with some woodgrain streaking:
PM me for coin photography equipment, or visit my website:
@RogerB said:
Silver color is not necessarily silver metal; same for copper color. The means are available to know not guess. Use it.
Thanks for the correction. I should have posted "streak of silver color. Not interested in what it is as I don't own this one. I have similar coins but they are in the bank and the silver COLORED streaks are larger. All I have seen have been rolled into the planchet so it could be silver, nickel, or even a steel filing. It is not iron. Nickel is the best guess as it is not tarnished.
Good to have the potassium and manganese contamination information. With sufficient date it might become part of a way to authenticate real bronze 1943 cents.
A production environment, such as the mints, is always filled with micro contaminates as well as macro materials. To assess a coinage alloy, one should have several hundred individual specimen measurements, then calculate the mean and median, plus standard deviation. Outliers would be expected. Presence of potassium and manganese would be expected to vary with the pre-melt cleaning of cases, plus exposure to Mint contamination from 5-cent coin alloy.
PS: Aluminum contamination should also be expected - the 5-cent alloy actually included a little aluminum that was used to volatilize oxides.
@RogerB said:
Good to have the potassium and manganese contamination information. With sufficient date it might become part of a way to authenticate real bronze 1943 cents.
A production environment, such as the mints, is always filled with micro contaminates as well as macro materials. To assess a coinage alloy, one should have several hundred individual specimen measurements, then calculate the mean and median, plus standard deviation. Outliers would be expected. Presence of potassium and manganese would be expected to vary with the pre-melt cleaning of cases, plus exposure to Mint contamination from 5-cent coin alloy.
PS: Aluminum contamination should also be expected - the 5-cent alloy actually included a little aluminum that was used to volatilize oxides.
I don't think any "shellcase" composition Cents were made until at least 1944 (I have personally never seen any) or 1945 (I've seen mostly S-Mint but some P-Mint also look to be shellcase). So 1943 coppers would likely not have any shellcase composition elements in the mix. Do you have a scenario where 1943 coppers could have shellcase elements?
PM me for coin photography equipment, or visit my website:
"So 1943 coppers would likely not have any shellcase composition elements in the mix."
That's the point. If a "1943 bronze" cent showed those contaminants or more than a trace of tin, the composition would be inconsistent with the 1942 planchet alloy used from May-Dec 1942. A legitimate error made from a 1942 planchet stuck in a tote bin, should be copper and zinc with a trace of tin. Late-year contamination from manganese might be present but not potassium.
Rick is on Vacation but it is time to "bump this thread."
So far I think we can all agree that "woodies" are caused by an improper mixing of a coin's alloys. I posted an image of block crystals of a different composition from the surrounding surface. Crystals in metal are common and depend on cooing/age/whatever.
I have a problem calling these crystals "ORANGE PEEL" as used by metallurgists because numismatists use that term for another characteristic found on our coins.
That caused this thread to evolve into a discussion of "orang peel" and its causes. One member has stated it is not found on silver coins. This is NOT TRUE! Some say the effect is caused by the annealing temperature of the planchet. Others believe it is due to the dies. BOTH MAY BE CORRECT.
However, in another thread here, Mr. Carr made some comments on a Peace dollar (with orange peel) he made and said it resulted from his die. I'm going to try to find out how to paste my question to him and his answer into this thread. I know I'm suppose to create a file first but....
@RogerB said:
RE: "So far I think we can all agree that "woodies" are caused by an improper mixing of a coin's alloys."
No. Show me the metallurgical analysis, then we can agree on what these empirical tests demonstrate.
I've already written that in the 1970's, the folks at Treasury who analyzed the output of all our Mints told us that (improper mixture) was the reason for the streaks. I assure you they were aware of the problem and did not wish to be striking what they called "Zebra cents."
What you have asked me to do is like proving a car tire is made of a rubber compound. Therefore I'm not interested in your challenge. Folks can believe me or not. However, I will say this: One day in your research, you are going to stumble upon that answer all by yourself and write about it in a book! Perhaps the second edition of From Mine to Mint! .
Comments
I would love to see some phase diagrams produced from early Lincolns and IHCs. This I old-fashioned physical chemistry/metallurgy, and academics aren't really interested in this sort of thing anymore.
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
XRF surface spot analysis of a dozen or so cents should help identify alloy differences. XRD could determine phase.
True, but I would like to see what happens as a function of temperature---through the melting and cooling processes.
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
OK. Now, let's get some of those 1909-VDB proofs as samples....
Cool! You will donate your coin (or buy one) for this effort, won't you? And I would be pleased to support you to the tune of $100--I'm a big spender--when you publish the results. I might even say nice things about the paper.
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
OK...let me pick one from the original roll.
LOL, yes we do: Lincoln cent composition (1909-1958)
.950 Copper
.050 Tin and Zinc
I see a lot of "woodgrain toning" on copper but I really like the more dramatic differences when the metals don't mix properly.
I even have a two cent proof (in a doily holder) with the woodgrain look.
The Penny Lady®
@ThePennyLady
I can see why you like those examples, thanks for posting them
Successful transactions with : MICHAELDIXON, Manorcourtman, Bochiman, bolivarshagnasty, AUandAG, onlyroosies, chumley, Weiss, jdimmick, BAJJERFAN, gene1978, TJM965, Smittys, GRANDAM, JTHawaii, mainejoe, softparade, derryb
Bad transactions with : nobody to date
No. You are confusing the macro alloy with the micro-alloy on a coin's surface. The first is a bulk measurement (or actually an assumption). The second is the alleged segregation of the elements constituting the alloy into patterns that oxidize differently. This segregation is supposed to produce the "wood grain" effect.
(PS: The proportions of tin, zinc and copper varied somewhat. After mid-Spring 1942, there was almost no tin.)
I think Roger's point is that there could be an uneven distribution of metals. Personally, I would be surprised, but stranger things have happened.
hemical composition - and that is the fundamental question.)
This is interesting. There was no tin. Was there more zinc, more copper or both?
All you have posted is that Tin is no longer used. That makes the composition of the streaks on those dates even easier to determine.
The streaks on these coins usually goes deeper than the surface. Decades ago we proved it to ourselves. Unfortunately, a circulated Lincoln "Woodie" was lost to posterity.
I'm reporting you to the ASPCC (American Society for the Prevention of Cruelty to Coins).
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
Go ahead, nothing will happen to me. I'm a charter board member of the CDOA (Coin Dippers of America). Thus, I have been given dispensation long ago for any coins in my care that I may destroy.
Repent!!!!
I did about 45 years ago, after I destroyed a gem 1918 Standing Liberty quarter---given to me by my grandmother---by overdipping. I totally stripped it, leaving no hit of luster left. Haven't touched the stuff since.
RMR: 'Wer, wenn ich schriee, hörte mich denn aus der Engel Ordnungen?'
CJ: 'No one!' [Ain't no angels in the coin biz]
This is doubly interesting. How deep did it go? Oxidation [with or without actual oxygen] should not happen below the surface unless there is a contaminant in the melt. So, if the woodsie Lincoln didn't leave the mint already grainy and the streaks run deep, it argues for some kind of foreign substance. If the woodsie Lincoln left the mint already grainy, wouldn't someone have noticed?
My condolences on your loss.
Look in the thread. Mint Red Lincoln's exist with bright brass streaks - as struck. The colors are not due to the environment, foreign substances, or oxidation. Oxidation only changes the colors.
Even greater reason to know the composition of "streaks." We don't have to depend on guesses and arcane assumptions. I do not understand the resistance to obtaining objective data; is it to use the available supply of emotional excuses, or to protect the "received ignorance" of the past, or something else ?
Chris is a metallurgist.
Well then, I'm with Roger. If there are bright brass streaks as struck, those streaks would have to have a composition difference. That composition difference could be an alloy difference, a foreign substance in the mix, oxidation or some other chemical process.
"Oxidation", "sulfurization" and other chemical process can happen with aging but they are NOT strictly defined by aging.
What is the resistance to chemical analysis of the streaks? XRD/XRF is much less invasive than whatever you did to the woodsie Lincoln back in the day.
Wood Grain effect refers to a specific type of toning. To my knowledge
Copper coins were never struck with wood grain toning. . It was developed
later.
The earliest examples of wood grain
Toning, that I have seen were on 1864
Bronze Indian cents. The most common copper coins with wood grain toning
are 1909 Lincoln cents.
The greatest challenge for TPG
Is determining whether the coin should be graded red or red/brown. I can state
about an 1872 Indian cent with totally obvious wood grain effect toning
graded as ms 66 r/b. It was sold for
$ 10,000 by Angel Dees to an upgrader
who got a grade of ms 66 red from
PCGS. The coin was immediately
sold to an active set registry participant
for $ 60,000. To make the story short,
PCGS wound up buying the coin back
and down graded it to 66 r/b.
Many people in this thread are confusing streaky toning as wood grain.
It is not toning with a wood grain effect
Orange peel has to do with the skin on copper and gold coins.
Also streakiness due to chemically
altered coins has nothing to do with
Wood grain effect toning. Wood grain effect toning is a completely natural
Occurance.
Lastly to answers Rogers question
If a metallurgical analysis has ever been done on a wood grained copper coin, not
to my knowledge.
@STEWARTBLAYNUMIS
Very nice explanation, thanks
Successful transactions with : MICHAELDIXON, Manorcourtman, Bochiman, bolivarshagnasty, AUandAG, onlyroosies, chumley, Weiss, jdimmick, BAJJERFAN, gene1978, TJM965, Smittys, GRANDAM, JTHawaii, mainejoe, softparade, derryb
Bad transactions with : nobody to date
All metals handled by our mints were subject to possible contamination during handling. The most commonly discussed was "fire scale" which was often seen in copper melts and found in rolled out ingots. Metal flecks could get on strips and be rolled into the metal, ending up in struck coins. As explained by members in earlier posts, a tiny spot of inconsistency or surface contamination could be rolled out into oval streaks of indeterminate length. In short, a lot of things could produce wood grain appearance or alloy inconsistency leading to wood grain. But our bottom line is: What are the metallurgical differences that result in visible wood grain?
Anyone care to provide unslabbed coins for examination or professional lab services to do the tests?
Duh, If I strike a coin on a .999 fine copper planchet it will be copper color. If I strike a coin on a planchet that is .999 fine copper on the right half and yellow brass on the other half I'm going to have a brilliant, frosty, original coin that is Red-pink on one side and yellow brass on the other AS STRUCK! Why complicate this with fantom impurities?
I have my eye on a wood-grained 1937 proof Buffalo nickel a friend has, PCGS PR65. It is marked as a Mirrored type, but it is a Satin. You either love it or hate it. It should lower the price due to appearance since most people want their proofs to be shiny and silvery, so I have to make him the proverbial "offer he can't refuse."
As a side note, not that many shell casings were used to make sense. It was a publicity stunt that was impractical.
This ripple effect is seen quite a bit on modern British proof coins, and I assumed it was due to their practice of hand-polishing their dies, rather than just lapping them on a table.
MS62BN
Gonna get me a $50 Octagonal someday. Some. Day.
Sorry, but your comment is completely false. If you pick up a copy of Pattern and Experimental Pieces of WW-II you can read about what was done to recycle brass military shell casings for US Mint coinage.
Short version: Brass shell cases, mostly 50 cal., were a problem for military training bases. Test batches were sent to the San Francisco Mint in 1943 but there was so much zinc volitization on melting, and the initial volume so great that the mints could not deal with the material that was shipped in boxcars. The military then shipped the cases to a contractor who melted the brass, cast it into usable bars, and sent it to US Mints. There, the bars were melted under makeshift collection hoods and sufficient pure copper was added to bring the alloy to 95% Cu, 4.9% Zn and a trace of tin. This was used for all one-cent coinage from 1944 through part of 1947 and was entirely satisfactory. Shell case cents have the same alloy as late 1942 cents, and the same basic alloy was used after the supply of shell cases was exhausted.
(Note: Brass shell cases cannot be recycled directly into new cases. The brass becomes brittle and cases made from it are not strong.)
the impurity was only one possibility. You could verify the composition difference of the brass versus copper as well. You are ASSUMING that you know there is a specific alloy difference rather than simply verifying it with a simple test.
The only thnig anyone can assume is I'm ZZZZZZZZZZZZZzzzzzzzzzzzzzzzzzzzzzzzzz.
The proposition is very straight forward: Any change in color, even locally, must have a cause. Careful, professional XRF measurements can determine if alloy segregation or contamination are a cause.
Would this be a woody? The coin exhibits bright orange all over but not in this cell pic.
Good thread topic.
Does anyone know if the woodgrain appearance is present on any Lincoln Memorial Cents and on any Lincoln brilliant proof cents from 1936 through 1964?
Just took an image of a 1914-D 1c with a streak of silver. I've seen this several times before just as a silver coin with copper (much more common). I'll post it this week.
Silver color is not necessarily silver metal; same for copper color. The means are available to know not guess. Use it.
The only XRF analysis I have seen on shellcase Cents showed potassium and manganese in the brightly-colored areas. These elements are present in the primers on WW2 ammo, so this is the likely source for the "shellcase" color.
Here's a 46-S Shellcase Cent, with some woodgrain streaking:
http://macrocoins.com
Thanks for the correction. I should have posted "streak of silver color. Not interested in what it is as I don't own this one. I have similar coins but they are in the bank and the silver COLORED streaks are larger. All I have seen have been rolled into the planchet so it could be silver, nickel, or even a steel filing. It is not iron. Nickel is the best guess as it is not tarnished.
Good to have the potassium and manganese contamination information. With sufficient date it might become part of a way to authenticate real bronze 1943 cents.
A production environment, such as the mints, is always filled with micro contaminates as well as macro materials. To assess a coinage alloy, one should have several hundred individual specimen measurements, then calculate the mean and median, plus standard deviation. Outliers would be expected. Presence of potassium and manganese would be expected to vary with the pre-melt cleaning of cases, plus exposure to Mint contamination from 5-cent coin alloy.
PS: Aluminum contamination should also be expected - the 5-cent alloy actually included a little aluminum that was used to volatilize oxides.
My Type III Indian Cent resembles that remark;
BST transactions: dbldie55, jayPem, 78saen, UltraHighRelief, nibanny, liefgold, FallGuy, lkeigwin, mbogoman, Sandman70gt, keets, joeykoins, ianrussell (@GC), EagleEye, ThePennyLady, GRANDAM, Ilikecolor, Gluggo, okiedude, Voyageur, LJenkins11, fastfreddie, ms70, pursuitofliberty, ZoidMeister,Coin Finder, GotTheBug, edwardjulio, Coinnmore, Nickpatton, Namvet69,...
I don't think any "shellcase" composition Cents were made until at least 1944 (I have personally never seen any) or 1945 (I've seen mostly S-Mint but some P-Mint also look to be shellcase). So 1943 coppers would likely not have any shellcase composition elements in the mix. Do you have a scenario where 1943 coppers could have shellcase elements?
http://macrocoins.com
"So 1943 coppers would likely not have any shellcase composition elements in the mix."
That's the point. If a "1943 bronze" cent showed those contaminants or more than a trace of tin, the composition would be inconsistent with the 1942 planchet alloy used from May-Dec 1942. A legitimate error made from a 1942 planchet stuck in a tote bin, should be copper and zinc with a trace of tin. Late-year contamination from manganese might be present but not potassium.
OK, makes sense. Potassium should be a very identifiable marker.
http://macrocoins.com
Unless they soaked the planchets in rotting bananas....
Rick is on Vacation but it is time to "bump this thread."
So far I think we can all agree that "woodies" are caused by an improper mixing of a coin's alloys. I posted an image of block crystals of a different composition from the surrounding surface. Crystals in metal are common and depend on cooing/age/whatever.
I have a problem calling these crystals "ORANGE PEEL" as used by metallurgists because numismatists use that term for another characteristic found on our coins.
That caused this thread to evolve into a discussion of "orang peel" and its causes. One member has stated it is not found on silver coins. This is NOT TRUE! Some say the effect is caused by the annealing temperature of the planchet. Others believe it is due to the dies. BOTH MAY BE CORRECT.
However, in another thread here, Mr. Carr made some comments on a Peace dollar (with orange peel) he made and said it resulted from his die. I'm going to try to find out how to paste my question to him and his answer into this thread. I know I'm suppose to create a file first but....
RE: "So far I think we can all agree that "woodies" are caused by an improper mixing of a coin's alloys."
No. Show me the metallurgical analysis, then we can agree on what these empirical tests demonstrate.
I've already written that in the 1970's, the folks at Treasury who analyzed the output of all our Mints told us that (improper mixture) was the reason for the streaks. I assure you they were aware of the problem and did not wish to be striking what they called "Zebra cents."
What you have asked me to do is like proving a car tire is made of a rubber compound. Therefore I'm not interested in your challenge. Folks can believe me or not. However, I will say this: One day in your research, you are going to stumble upon that answer all by yourself and write about it in a book! Perhaps the second edition of From Mine to Mint!
.