Don’t ask me why it’s higher than 90% maybe the mixture on that particular batch of silver? Interesting for sure and I guarantee the Morgan is genuine...
The Annual Assay Commission reports never show a discrepancy like the ones illustrated. Melts were condemned long before any part of the melt reached this level. Although silver segregation was well known (but not understood at that time) it was never this high. (See From Mint to Mint.)
Please keep in mind that XRF is highly surface sensitive. While it may well need calibration, all the readings really tell you is the surface concentration of silver.
Here, you can read this about the surface enrichment of silver:
@jmlanzaf said:
Please keep in mind that XRF is highly surface sensitive. While it may well need calibration, all the readings really tell you is the surface concentration of silver.
Here, you can read this about the surface enrichment of silver:
@asheland said:
Don’t ask me why it’s higher than 90% maybe the mixture on that particular batch of silver? Interesting for sure and I guarantee the Morgan is genuine...
My guess is that it is only looking at the surface. The alloy may not have been mixed thoroughly.
That is really cool Asheland and thanks for taking the time to do this! I know nothing about them but an X-Ray looks inside things right? If this only sees the surface, it would not detect lead filled gold for instance, I am thinking.
@Wabbit2313 said:
That is really cool Asheland and thanks for taking the time to do this! I know nothing about them but an X-Ray looks inside things right? If this only sees the surface, it would not detect lead filled gold for instance, I am thinking.
It depends on the strength of the x-ray beam. Coming from a handheld device, it will be weak and will only penetrate the surface but so far. As x-rays pass through, the energy is absorbed or deflected. Maybe documentation that comes with the machine will give @asheland some insight.
@asheland said:
Don’t ask me why it’s higher than 90% maybe the mixture on that particular batch of silver? Interesting for sure and I guarantee the Morgan is genuine...
Can this be used as a sales pitch on eBay (i.e. silver enriched Morgan, silver coated gold Morgan, etc.)?
Yes the article is great! 4. Discussion are the answer(s). Thanks for posting this. So the xrf machine is working given the manner in which it is "reading" the metal surface. Peace Roy
@jmlanzaf ....Thank you for that very informative article...Clearly explains surface enrichment in Ag/Cu alloys.... and make it likely the XRF in the OP is correct (calibration questions aside). Cheers, RickO
@jmlanzaf said:
Please keep in mind that XRF is highly surface sensitive. While it may well need calibration, all the readings really tell you is the surface concentration of silver.
Here, you can read this about the surface enrichment of silver:
Great article. However, I wonder if this is applicable to modern coinage. The max Ag in the study was 80% and the samples were melted in a clay/graphite crucible and allowed to cool in the furnace. Would modern metallurgy with 90% Ag and the significantly faster cooling rates yield similar surface enrichment?
I believe the OPs XRF simply needs calibration. Surface enrichment is an interesting topic but without data on modern coinage, I don’t think surface enrichment is contributing much to the variation in the OPs results.
@RogerB said:
The Annual Assay Commission reports never show a discrepancy like the ones illustrated. Melts were condemned long before any part of the melt reached this level. Although silver segregation was well known (but not understood at that time) it was never this high. (See From Mint to Mint.)
Was the XRF calibrated prior to use?
Not really sure, my friend owns it, he just lets me use it occasionally.
I have had about a dozen coins tested via EDXRF at a laboratory here in New Mexico. I can say that results do vary depending on the type of test and the standards of calibration the machine is using as a baseline.
For example,
I have a 1943 LMC that has become a sort of per project for me. When it is tested for oxides the cent reads 91% Fe203 or Iron Oxide with significant levels (not trace) of Aluminum, Chromium, Silicone, Calcium etc. The composition based on those results tells me that it is not the low grade 1010 steel that the usual run of the mill 1943's are made of.
I had the cent tested again, this time with different results, because the basline standard of the second test was completely different, the type of results I received were different. The new test stated 99% Iron, but now showed that it contains Molybdenum, which was used during the experiments after production started in 1943.
Needless to say, if you want to know what your Coin is composed of, a hand held scanner is only going to leave you with more questions, not answers. I found a laboratory here in the Albuquerque area who happens to have previous experience testing coins, (A late 1800's heist of silver coinage was transported by revolutionary banditos to a seized mint in Mexico, melted down and reminted as mexican coins. Mexican coinage was tested to see if they were created from US Silver Dollars.) The Dr. who owns the lab only charges 35 to 50 dollars. That's worth it to me to have credentials behind the testing.
By the way, thanks for starting a tread on the subject and I hope you can find the professional results that you want and need.
@jmlanzaf said:
Please keep in mind that XRF is highly surface sensitive. While it may well need calibration, all the readings really tell you is the surface concentration of silver.
Here, you can read this about the surface enrichment of silver:
Great article. However, I wonder if this is applicable to modern coinage. The max Ag in the study was 80% and the samples were melted in a clay/graphite crucible and allowed to cool in the furnace. Would modern metallurgy with 90% Ag and the significantly faster cooling rates yield similar surface enrichment?
I believe the OPs XRF simply needs calibration. Surface enrichment is an interesting topic but without data on modern coinage, I don’t think surface enrichment is contributing much to the variation in the OPs results.
There are other references that show similar effects. Here, you read them all. People love to make up facts rather than look them up.
@Wjpmill said:
I have had about a dozen coins tested via EDXRF at a laboratory here in New Mexico. I can say that results do vary depending on the type of test and the standards of calibration the machine is using as a baseline.
For example,
I have a 1943 LMC that has become a sort of per project for me. When it is tested for oxides the cent reads 91% Fe203 or Iron Oxide with significant levels (not trace) of Aluminum, Chromium, Silicone, Calcium etc. The composition based on those results tells me that it is not the low grade 1010 steel that the usual run of the mill 1943's are made of.
I had the cent tested again, this time with different results, because the basline standard of the second test was completely different, the type of results I received were different. The new test stated 99% Iron, but now showed that it contains Molybdenum, which was used during the experiments after production started in 1943.
Needless to say, if you want to know what your Coin is composed of, a hand held scanner is only going to leave you with more questions, not answers. I found a laboratory here in the Albuquerque area who happens to have previous experience testing coins, (A late 1800's heist of silver coinage was transported by revolutionary banditos to a seized mint in Mexico, melted down and reminted as mexican coins. Mexican coinage was tested to see if they were created from US Silver Dollars.) The Dr. who owns the lab only charges 35 to 50 dollars. That's worth it to me to have credentials behind the testing.
By the way, thanks for starting a tread on the subject and I hope you can find the professional results that you want and need.
William.
I imagine that there are many trace elements to be found in recycled (i.e., "scrap") steel.
TD
Numismatist. 50 year member ANA. Winner of four ANA Heath Literary Awards; three Wayte and Olga Raymond Literary Awards; Numismatist of the Year Award 2009, and Lifetime Achievement Award 2020. Winner numerous NLG Literary Awards.
A precious metals analyzer that only, or was even primarily, provided information about the composition of the Surface, would be next to (or worse than) useless.
Technology is great stuff - but it has to be used by knowledgeable technicians, and the results properly interpreted.
All US Mint assays of the Morgan dollar period were physical assays taken a multiple stages of metal processing and coinage. No US silver coin could have 94% silver and there would never be a discrepancy of almost 1% between one face and the other. Every delivery was independently checked by special assay in Washington and the coins were supposed to remain unreleased until results confirmed correct weight and alloy. (Sometime they were paid out too early, but I've never see a special assay result anywhere near the posted results.) Any large discrepancy would have triggered a major investigation and probably several removals from office.
The posted article is interesting but not related to modern coinage.
@RogerB- if that's you than you already know your book is on my wish list and am familiar with my coin I'm referring to. (Is that really you?)
In case you haven't read it or don't own it, there is a fantastic reference written by Roger Burdette on Trials, patterns and Experimental Cents of the WW2 era entitled, yep, United States Pattern & Experimental Pieces of WWII.
Ill get the XRF data and device info etc, up for you guys to read later after I get up this afternoon.
@jmlanzaf said:
Please keep in mind that XRF is highly surface sensitive. While it may well need calibration, all the readings really tell you is the surface concentration of silver.
Here, you can read this about the surface enrichment of silver:
Great article. However, I wonder if this is applicable to modern coinage. The max Ag in the study was 80% and the samples were melted in a clay/graphite crucible and allowed to cool in the furnace. Would modern metallurgy with 90% Ag and the significantly faster cooling rates yield similar surface enrichment?
I believe the OPs XRF simply needs calibration. Surface enrichment is an interesting topic but without data on modern coinage, I don’t think surface enrichment is contributing much to the variation in the OPs results.
There are other references that show similar effects. Here, you read them all. People love to make up facts rather than look them up.
I have no disagreement with surface enrichment of ancient coins. The original article you posted was interesting. I also appreciate you doing a lit search, however, these articles are on Ag-Au alloys, Ancients and one on Ag-Pd alloys. There is nothing on 90Ag10Cu alloys using modern smelting methods.
You could even say that the Beck et.al, paper makes an argument against surface enrichment on modern coins because they show that slow cooling allows time for silver rich regions to form near the surface. I would expect quenching to inhibit the formation these regions by quickly solidifying the melt before it had a chance to segregate. Yes, I know it's a stretch, but no more so than extrapolating data from ancient coins onto Morgan dollars.
If you have any references on Ag surface enrichment of modern (post 1850) US or European coinage, I would love to read it. I don't think it's likely, but will always love to "listen to the data".
So back to the OP; I don't believe surface enrichment is a viable explanation for the variation in Ag levels
@RogerB- if that's you than you already know your book is on my wish list and am familiar with my coin I'm referring to. (Is that really you?)
In case you haven't read it or don't own it, there is a fantastic reference written by Roger Burdette on Trials, patterns and Experimental Cents of the WW2 era entitled, yep, United States Pattern & Experimental Pieces of WWII.
Ill get the XRF data and device info etc, up for you guys to read later after I get up this afternoon.
@RogerB- if that's you than you already know your book is on my wish list and am familiar with my coin I'm referring to. (Is that really you?)
In case you haven't read it or don't own it, there is a fantastic reference written by Roger Burdette on Trials, patterns and Experimental Cents of the WW2 era entitled, yep, United States Pattern & Experimental Pieces of WWII.
Ill get the XRF data and device info etc, up for you guys to read later after I get up this afternoon.
Yep. Right here. From Mine to Mint will also answer the questions from 'Oldhoopster' about quenching/cooling procedures for silver and gold ingots. Thanks for the nice comments about United States Pattern & Experimental Pieces of WWII -- a lot of research went into that!
@RogerB said:
Technology is great stuff - but it has to be used by knowledgeable technicians, and the results properly interpreted.
All US Mint assays of the Morgan dollar period were physical assays taken a multiple stages of metal processing and coinage. No US silver coin could have 94% silver and there would never be a discrepancy of almost 1% between one face and the other. Every delivery was independently checked by special assay in Washington and the coins were supposed to remain unreleased until results confirmed correct weight and alloy. (Sometime they were paid out too early, but I've never see a special assay result anywhere near the posted results.) Any large discrepancy would have triggered a major investigation and probably several removals from office.
The posted article is interesting but not related to modern coinage.
I disagree. That article is simply one of dozens if not hundreds of articles about silver segregation in alloys. The phenomenon exists even at very low silver content. While I find no specific references on modern Mint planchets, the phenomenon seems to be virtually ubiquitous in binarey or ternary alloys of silver.
[silver segregation in alloys](silver segregation in alloys "silver segregation in alloys")
Quant'X Thermo Scientific Energy Dispersive XRF. The machine looks like a very large printer or copy machine.
I'm not an expert in the testing by any means. When I was there hanging out during one of my tests, I asked if the DR. Would place the coin on it's side and if the results would be different, as the x-rays would penetrate through it's side. There is a groove in the side of the coin so that's why I asked. The results were the same.
If you scroll down the page on this link, you can find out more about the machine and testing procedures.
I'll disagree with your disagree, but agreeably. Ancient silver and modern refined silver are very different critters, and the analysis of composition also differs. Ancient silver is especially prone to crystallization - the phenomenon that makes Greek tetradrachms and decadrachms so fragile. Ancient silver is also subject to many factors that affect surface purity and alloy (as the L. Beck, et al article mentions). These do not usually impact modern silver, yet there are other environmental factors to consider.
Mint M&R people and Assayers deliberately biased silver ingots - especially dollars and halves - so that the overall assay was slightly low, but the rolled strip center, where the blanks were cut, was 0.900.
The effect is more pronounced at lower silver concentrations, but US mints did not refine to low purity. (They also did not like getting doré silver that requires a lot of work to refine.)
I realize that the effects were probably minimal, and this has nothing to do with the percentages shown in the OP, but what effect did the blanching of planchets have on the surface fineness?
After WW2 Australia changed its silver to a quartenary alloy. That I think was 500 silver, 400 copper, 50 zinc and 50 nickel. Before striking the planchets were severely pickled so that the surfaces were very high grade silver. They looked great when new. But after a bit of circulation the inside quickly showed through on the high points and toned a sickly yellow.
Numismatist. 50 year member ANA. Winner of four ANA Heath Literary Awards; three Wayte and Olga Raymond Literary Awards; Numismatist of the Year Award 2009, and Lifetime Achievement Award 2020. Winner numerous NLG Literary Awards.
RE: "...what effect did the blanching of planchets have on the surface fineness?"
"The necessity of accuracy and the difficulty in maintaining a uniform standard is appreciated only by those who are in daily touch with the work.
"The mixing of gold and silver, while in a heated condition, with their respective alloys, casting into ingots, rolling and cutting into planchets, annealing and whitening, and finally the stamping, all depend, more or less, upon the skill and judgment of the operator.
"No set rules can be laid down for this work that will give uniform results for the different melts, or even for two strips in the same heat, which often vary beyond the tolerance, although they have passed through identical operations, so far as human judgment can determine."
"The planchets are then annealed by rotary-heating machines and cleaned with a diluted solution of sulphuric acid." A 1903 article by Church notes that planchets go direct from a rotary annealing furnace to the whitening solution without exposure to air.
["MINTING MACHINERY AND APPLIANCES" by EDWIN S. CHURCH. Superintendent of Machinery U. S. Mint, Philadelphia. FRANKLIN INSTITUTE, December 1901. pp.401-419]
As noted also in From Mint to Mint, this would enhance the surface silver slightly by removal of copper oxide ("fire scale"), alloy copper and other contaminants. Planchets were not mentioned as being soaked in acid for a long time - only long enough for visual whitening. (See also the illustration from the New Orleans Mint of silver in various steps of the operation.
A surface enhancement of nearly 5% seems very unlikely. However, all Mint assays were on bulk samples - surface and sub-surface analysis was impossible when silver dollars were current.
Can additional Morgans of this date & mint be analyzed? As with one-cent coin composition, maybe our assumptions are not as firmly based as we thought. The means exist to expand out knowledge, if those with available resources will support the research.
The coin for the test was just a random coin pulled from the junk pile at my friend's shop. Highly unlikely that I could find the exact coin again to re-test.
OK. However, my point is that surface elemental analysis of a bunch of Morgans might show similar silver enhancement not attributable to alloy but to "whitening" of planchets before coins were struck. Although this would not change assay reports if true, it would add to a better understanding of the full US Mint coining operation, and require updating of materials so that future collectors are not mislead.
Also, it might give us additional tools to combat counterfeits of the correct alloy.
@RogerB said:
OK. However, my point is that surface elemental analysis of a bunch of Morgans might show similar silver enhancement not attributable to alloy but to "whitening" of planchets before coins were struck. Although this would not change assay reports if true, it would add to a better understanding of the full US Mint coining operation, and require updating of materials so that future collectors are not mislead.
Also, it might give us additional tools to combat counterfeits of the correct alloy.
So you may be starting to disagree with your disagree of my disagree?
asheland
Posts: 22,694 ✭✭✭✭✭
Comments
@Wabbit2313
The reverse:
My YouTube Channel
Don’t ask me why it’s higher than 90%
maybe the mixture on that particular batch of silver? Interesting for sure and I guarantee the Morgan is genuine...
My YouTube Channel
Perhaps the device requires calibration to reference standards, and/or the operator requires training in the standard operating procedure.
Liberty: Parent of Science & Industry
I used it properly, I’m guessing it needs calibration.
My YouTube Channel
Lead and iron?
The iron is only in the obverse
Liberty: Parent of Science & Industry
Let's get it calibrated in the next week. LOL!!!
The Annual Assay Commission reports never show a discrepancy like the ones illustrated. Melts were condemned long before any part of the melt reached this level. Although silver segregation was well known (but not understood at that time) it was never this high. (See From Mint to Mint.)
Was the XRF calibrated prior to use?
Please keep in mind that XRF is highly surface sensitive. While it may well need calibration, all the readings really tell you is the surface concentration of silver.
Here, you can read this about the surface enrichment of silver:
bsaxton.com/stuff/silverenrich.pdf
I have a calibrated sigma metalic pro unit but it sits in the closet in its case.Never really used it. But its calibrated.
It is interesting to see the numbers! It needs to be calibrated, but this is still fascinating to see.
YN Member of the ANA, ANS, NBS, EAC, C4, MCA, PNNA, CSNS, ILNA, TEC, and more!
Always buying numismatic literature and sample slabs.
My guess is that it is only looking at the surface. The alloy may not have been mixed thoroughly.
Of course the others make a good point about calibration issues as well.
I want one of these XRF devices.
That is really cool Asheland and thanks for taking the time to do this! I know nothing about them but an X-Ray looks inside things right? If this only sees the surface, it would not detect lead filled gold for instance, I am thinking.
It depends on the strength of the x-ray beam. Coming from a handheld device, it will be weak and will only penetrate the surface but so far. As x-rays pass through, the energy is absorbed or deflected. Maybe documentation that comes with the machine will give @asheland some insight.
May I borrow the device @asheland ? I'd go through all of my jewelry
Can this be used as a sales pitch on eBay (i.e. silver enriched Morgan, silver coated gold Morgan, etc.)?
If y'all actually read the article I posted, you'd have your answer without the need to speculate.
Yes the article is great! 4. Discussion are the answer(s). Thanks for posting this. So the xrf machine is working given the manner in which it is "reading" the metal surface. Peace Roy
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@jmlanzaf ....Thank you for that very informative article...Clearly explains surface enrichment in Ag/Cu alloys.... and make it likely the XRF in the OP is correct (calibration questions aside). Cheers, RickO
Attractive "rust colored" ....toning.... on the obverse. A real treasure for the discriminating numism.......
Great article. However, I wonder if this is applicable to modern coinage. The max Ag in the study was 80% and the samples were melted in a clay/graphite crucible and allowed to cool in the furnace. Would modern metallurgy with 90% Ag and the significantly faster cooling rates yield similar surface enrichment?
I believe the OPs XRF simply needs calibration. Surface enrichment is an interesting topic but without data on modern coinage, I don’t think surface enrichment is contributing much to the variation in the OPs results.
Not really sure, my friend owns it, he just lets me use it occasionally.
My YouTube Channel
I have had about a dozen coins tested via EDXRF at a laboratory here in New Mexico. I can say that results do vary depending on the type of test and the standards of calibration the machine is using as a baseline.
For example,
I have a 1943 LMC that has become a sort of per project for me. When it is tested for oxides the cent reads 91% Fe203 or Iron Oxide with significant levels (not trace) of Aluminum, Chromium, Silicone, Calcium etc. The composition based on those results tells me that it is not the low grade 1010 steel that the usual run of the mill 1943's are made of.
I had the cent tested again, this time with different results, because the basline standard of the second test was completely different, the type of results I received were different. The new test stated 99% Iron, but now showed that it contains Molybdenum, which was used during the experiments after production started in 1943.
Needless to say, if you want to know what your Coin is composed of, a hand held scanner is only going to leave you with more questions, not answers. I found a laboratory here in the Albuquerque area who happens to have previous experience testing coins, (A late 1800's heist of silver coinage was transported by revolutionary banditos to a seized mint in Mexico, melted down and reminted as mexican coins. Mexican coinage was tested to see if they were created from US Silver Dollars.) The Dr. who owns the lab only charges 35 to 50 dollars. That's worth it to me to have credentials behind the testing.
By the way, thanks for starting a tread on the subject and I hope you can find the professional results that you want and need.
William.
There are other references that show similar effects. Here, you read them all. People love to make up facts rather than look them up.
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C33&q=surface+enrichment+of+silver&btnG=
@Wjpmill
to the boards.
My YouTube Channel
I imagine that there are many trace elements to be found in recycled (i.e., "scrap") steel.
TD
A precious metals analyzer that only, or was even primarily, provided information about the composition of the Surface, would be next to (or worse than) useless.
Liberty: Parent of Science & Industry
Fascinating.
What make and model is the XRF?
Also, do you see variation if you take multiple readings in the same place? Variation in multiple places on the same side?
Would tell us a lot about the units capabilities.
“In matters of style, swim with the current; in matters of principle, stand like a rock." - Thomas Jefferson
My digital cameo album 1950-64 Cameos - take a look!
Have you tried it on some 90% and some silver bars 99.9999 to see what they read on that scanner.
Technology is great stuff - but it has to be used by knowledgeable technicians, and the results properly interpreted.
All US Mint assays of the Morgan dollar period were physical assays taken a multiple stages of metal processing and coinage. No US silver coin could have 94% silver and there would never be a discrepancy of almost 1% between one face and the other. Every delivery was independently checked by special assay in Washington and the coins were supposed to remain unreleased until results confirmed correct weight and alloy. (Sometime they were paid out too early, but I've never see a special assay result anywhere near the posted results.) Any large discrepancy would have triggered a major investigation and probably several removals from office.
The posted article is interesting but not related to modern coinage.
BTW you can learn more about silver segregation in the book From Mine to Mint.
Unfortunately I cannot answer that. I just use it on rare occasions. I know very little about the machine.
My YouTube Channel
@cameonut, @ashland ill get back to you in this thread later today.
@RogerB- if that's you than you already know your book is on my wish list and am familiar with my coin I'm referring to. (Is that really you?)
In case you haven't read it or don't own it, there is a fantastic reference written by Roger Burdette on Trials, patterns and Experimental Cents of the WW2 era entitled, yep, United States Pattern & Experimental Pieces of WWII.
Ill get the XRF data and device info etc, up for you guys to read later after I get up this afternoon.
I have no disagreement with surface enrichment of ancient coins. The original article you posted was interesting. I also appreciate you doing a lit search, however, these articles are on Ag-Au alloys, Ancients and one on Ag-Pd alloys. There is nothing on 90Ag10Cu alloys using modern smelting methods.
You could even say that the Beck et.al, paper makes an argument against surface enrichment on modern coins because they show that slow cooling allows time for silver rich regions to form near the surface. I would expect quenching to inhibit the formation these regions by quickly solidifying the melt before it had a chance to segregate. Yes, I know it's a stretch, but no more so than extrapolating data from ancient coins onto Morgan dollars.
If you have any references on Ag surface enrichment of modern (post 1850) US or European coinage, I would love to read it. I don't think it's likely, but will always love to "listen to the data".
So back to the OP; I don't believe surface enrichment is a viable explanation for the variation in Ag levels
Welcome and looking forward for you waking up
Yep. Right here. From Mine to Mint will also answer the questions from 'Oldhoopster' about quenching/cooling procedures for silver and gold ingots. Thanks for the nice comments about United States Pattern & Experimental Pieces of WWII -- a lot of research went into that!
I disagree. That article is simply one of dozens if not hundreds of articles about silver segregation in alloys. The phenomenon exists even at very low silver content. While I find no specific references on modern Mint planchets, the phenomenon seems to be virtually ubiquitous in binarey or ternary alloys of silver.
[silver segregation in alloys](silver segregation in alloys "silver segregation in alloys")
Quant'X Thermo Scientific Energy Dispersive XRF. The machine looks like a very large printer or copy machine.
I'm not an expert in the testing by any means. When I was there hanging out during one of my tests, I asked if the DR. Would place the coin on it's side and if the results would be different, as the x-rays would penetrate through it's side. There is a groove in the side of the coin so that's why I asked. The results were the same.
If you scroll down the page on this link, you can find out more about the machine and testing procedures.
http://www.swxrflab.net/labfees.htm
RE: jmlanzaf
I'll disagree with your disagree, but agreeably. Ancient silver and modern refined silver are very different critters, and the analysis of composition also differs. Ancient silver is especially prone to crystallization - the phenomenon that makes Greek tetradrachms and decadrachms so fragile. Ancient silver is also subject to many factors that affect surface purity and alloy (as the L. Beck, et al article mentions). These do not usually impact modern silver, yet there are other environmental factors to consider.
Mint M&R people and Assayers deliberately biased silver ingots - especially dollars and halves - so that the overall assay was slightly low, but the rolled strip center, where the blanks were cut, was 0.900.
The effect is more pronounced at lower silver concentrations, but US mints did not refine to low purity. (They also did not like getting doré silver that requires a lot of work to refine.)
I realize that the effects were probably minimal, and this has nothing to do with the percentages shown in the OP, but what effect did the blanching of planchets have on the surface fineness?
After WW2 Australia changed its silver to a quartenary alloy. That I think was 500 silver, 400 copper, 50 zinc and 50 nickel. Before striking the planchets were severely pickled so that the surfaces were very high grade silver. They looked great when new. But after a bit of circulation the inside quickly showed through on the high points and toned a sickly yellow.
Asheland, scan your forehead!
@Wabbit2313 I’m thinking just that after all these discussions.
My YouTube Channel
Well I’ve concluded this machine is accurate. I scanned a 2014 silver eagle. Dead on:
My YouTube Channel
Was "Wabbit's" coin re-tested?
RE: "...what effect did the blanching of planchets have on the surface fineness?"
"The necessity of accuracy and the difficulty in maintaining a uniform standard is appreciated only by those who are in daily touch with the work.
"The mixing of gold and silver, while in a heated condition, with their respective alloys, casting into ingots, rolling and cutting into planchets, annealing and whitening, and finally the stamping, all depend, more or less, upon the skill and judgment of the operator.
"No set rules can be laid down for this work that will give uniform results for the different melts, or even for two strips in the same heat, which often vary beyond the tolerance, although they have passed through identical operations, so far as human judgment can determine."
"The planchets are then annealed by rotary-heating machines and cleaned with a diluted solution of sulphuric acid." A 1903 article by Church notes that planchets go direct from a rotary annealing furnace to the whitening solution without exposure to air.
["MINTING MACHINERY AND APPLIANCES" by EDWIN S. CHURCH. Superintendent of Machinery U. S. Mint, Philadelphia. FRANKLIN INSTITUTE, December 1901. pp.401-419]
As noted also in From Mint to Mint, this would enhance the surface silver slightly by removal of copper oxide ("fire scale"), alloy copper and other contaminants. Planchets were not mentioned as being soaked in acid for a long time - only long enough for visual whitening. (See also the illustration from the New Orleans Mint of silver in various steps of the operation.
A surface enhancement of nearly 5% seems very unlikely. However, all Mint assays were on bulk samples - surface and sub-surface analysis was impossible when silver dollars were current.
Can additional Morgans of this date & mint be analyzed? As with one-cent coin composition, maybe our assumptions are not as firmly based as we thought. The means exist to expand out knowledge, if those with available resources will support the research.
The coin for the test was just a random coin pulled from the junk pile at my friend's shop. Highly unlikely that I could find the exact coin again to re-test.
My YouTube Channel
OK. However, my point is that surface elemental analysis of a bunch of Morgans might show similar silver enhancement not attributable to alloy but to "whitening" of planchets before coins were struck. Although this would not change assay reports if true, it would add to a better understanding of the full US Mint coining operation, and require updating of materials so that future collectors are not mislead.
Also, it might give us additional tools to combat counterfeits of the correct alloy.
Shhhhh! Do you think the Chinese are listening? Peace Roy
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你认为中国人在听吗？我们会看到。
So you may be starting to disagree with your disagree of my disagree?