Research on US "brown nickels"

I have been doing some research on Canadian "brown" 5-cent coins, 1982 to 1992, and while a majority of the ones I find are instantly recognizable as environmental damage, I am find a small population of nice, clean brown nickels that are in excess of 80% copper when I test on the XRF in my lab. The post-1981 Canadian 5-cent planchets are supposed to be 75% copper and 25% nickel (like the US ones). Planchet size and weight conforms to Royal Canadian Mint tolerances for the 5-cent coins - so I think they are the result of a copper-rich alloy mixing error (possibly procured from an external smelter). I published my results in the Canadian Numismatic Journal in June of 2012.

I am now finding similar US 5-cent coins. Again, most are environmentally damaged, and within mint specifications (75% Cu / 25% Ni). But, then I find lustrous brown Liberty nickel with 81% copper and a brown buffalo nickel with almost 83% copper. Before I roll up my sleeves, and dive into a hunt of finding more US brown nickels and putting them under the XRF, are any of the US nickel error experts here able to tell me if there is published work already available on this subject matter?? My searches here, online in general, and in CONECA publications are coming up empty (exceptions to my searches are, of course, when nickels are struck on penny or foreign planchets - but that is not what I am talking about here).

 

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I am somewhat surprised, given the depth of error expertise here, at the lack of response. I can only assume very little has been published or documented on alloy mixing errors of US Cu-Ni nickels?

Here is an example, a 1924 Buffalo nickel, quite brown in colour. This particular coin is 81.96% Cu (supposed to be 75%), I published it as an example to the brown Canadian 5-cent coins we see, of similar elevated Cu values from 1982-1990, in The Canadian Numismatic Journal (June 2012).

Does anyone here have US nickels (Liberty, Buffalo, Jefferson) that look like this Buffalo nickel?? Are you willing to let me borrow those coins for (nondestructive) XRF analysis?? I would eventually want to publish the results, probably with CONECA.

 

Here is a recent Canadian example - this particular coin contains 80.28% Cu (RCM specifications are 75% Cu - 25% Ni). I am not sure if I have enough posts to allow anyone to contact me - but if anyone is interested in a copy of the paper I published on 'brown nickels' and alloy mixing errors in The Canadian Numismatic Journal, drop me a message on my 'home page' here and I can send a PDF out to you.

 

This is a topic I find very interesting, but I'm afraid I don't have much to contribute. Does your XRF provide a full-depth measurement, or is it weighted toward surface composition?

 

I have a dateless Buffalo nickel that is brown in color.

 

For some odd reason all of our newer coins not counting the cents will tone to a brillant deep copper color . now all of my graded and authenticated ultra detached leg 2005 nickels are a beautiful golden color. at first this bothered me but now I'm enjoying the way they look. brand new dimes and quarters will also do this if they have not been in circulation. I have found out by doing some experiments that when I gently wash the coins in warm water and soap then rinse them off then dry them with a super soft cloth they will not tone back to the brown or gold color.

This pretty much proves that whatever the mint is washing the coins with is the cause of this brown and gold color toning.

if you don't believe me get some coins directly from the mint in the collector rolls then open the rolls and leave the coins in a open box then look at them after about a month. if you don't want to open the rolls just take a look at the exposed coins at the end of the rolls.

I have plenty of naturaly toned golden brown nickels and quarters already in coin holders here somewhere. I can probably find them if anyone is interested in seeing them. PM me if you want to talk , I'm disabled and enjoy emails.

 

I have recently found one Liberty and three Jefferson nickels, also as brown as the Buffalo above. After analysis, all were above 80% Cu content....

I have the power of the beam cranked up pretty high, so I am positive there is penetration of the coin. In fact, I tested a Canadian chrome-plated 1944 5-cent, and it didn't even pick up the chrome plating, the beam penetrated right through it, and gave me an analysis of the coin's composition under the plating.

 

Have your results been confirmed by third parties with their own equipment?

 

The instrument I use, is one used in my daily research, in a Canadian federal government research institution (see my profile). The instrument is entirely new as of April 2011, and I am held to the highest research standards, much like any academic research institute. I am bound by professional (registered) and research ethics, and I apply the same practice whether it is with my soil samples using aqueous chemistry or XRF analysis of my coins. I am bringing my research passion to numismatics.

I routinely run registered calibration standards for each analysis. If the instrument passes the calibration standard, then it is accurate and precise. Why would I compare those results with a second instrument elsewhere, which may not have the same beam power, hardware/software setup and analytical protocols? I could send the coins for destructive analysis, but that tends to significantly reduce my investment and harshly impacts the grade of my error coins. :devil:

If you want the gory details, I use an INNOV-X X-5000 Series Bench Top Instrument, with a 10 Watt X-ray tube, 50 keV, 200 μA (max) and a silicon drift detector. Analyses were conducted in “Alloy” mode, which analyzes a suite of elements in two beams (Beam #1: Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Hf, Ta, W, Re, Ir, Pt, Au, Pb, Bi, Zr, Nb, Mo, Rh, LE, Pd, Ag, Sn, Sb; Beam #2: Ti, V, Cr, Mn, Fe, Co). The instrument was set up to run and repeat this two- beam analysis three times, for a total of 75 seconds, and results were generated from an average value of the three runs.

 

I don't have a clue what any of that means, so I'll just get it out. Nobody really cares that much because it's not something you'll easily pick up just by looking at a coin. It's not obvious like a cud or a clipped planchet, or a blank planchet. The fact I have to analyze the coin with a machine (and what sounds like a very, very expensive one at that) makes it rather difficult for me to care if my nickel is 75/25 or 80/20 or whatever. People care about improper planchet mixtures on LWC and LMC because they have that notorious "woodie" look. On nickels? If anything, I can see it being a negative.

With that said, I hope you find whatever you happen to be looking for. I hope you find some sucker out there that wants to pay you 1,000 times face for one of these. It'll give me something else to look for when I search through nickels.

 

Here's why I was asking about penetration depth.

I've bulk-"restored" a bunch of dateless cull Buffalo nickels in white vinegar (5% acetic acid). Looking strictly at the activity series, it should preferentially attack the nickel, sparing the copper, although I realize it's probably not that simple in an alloy.

I left a few of them in for a number of months. When I checked them, they had indeed turned dark coppery brown, and the supernatant liquid's color looked more like Ni2+ than Cu2+. I believe they were visibly thinner, although I don't think I actually dried and weighed them; I should go ahead and do that (they're in water now).

So, if a CuNi coin sustains damage in an acid environment, I'd expect the surfaces to be enriched in copper. Based on my own limited experimentation, it can produce the color change you've described as well. What I don't know is how the composition changes with depth. I'd be happy to provide a sacrificial nickel for you to grind down, measuring composition as you go, or cross-section and do a profile across the interior (if your spot size is small enough).

 

Hey that sounds like fun! I would use the SEM to analyze the freshly ground surface... alternatively, I could just take a slice, and run a laser ablation microprobe traverse right across the width of the coin...

Quite the contrary, they stick out like a sore thumb in any nickel junk bin. The Canadian counterparts are now sought out by error collectors, once we knew exactly what we were looking for...

 

My intent is not driven by profit, otherwise I would not share and publish my findings. It is driven by wondering why, asking questions and thinking how to answer those questions, and bringing a bit of science to a wonderful hobby. Part of the reason why I started this thread, was to see if any advanced error collectors here, or through a contact within the US, have already given this topic some or any thought and/or research. I prefer to do my homework first, so that if I decide to study this aspect of US coins, I don't step on any toes or unnecessarily re-invent the wheel... ultimately, I intend to write a paper, whereby those who are interested can have some interesting data to compare to.

Coins are a fascinating hobby - some people like to dive into details about the dies, machine doubling or different die matrices and hubs for tracking coins, other people, like me, wonder how the coins were made, what they were made of, and nuances therein - to each their own.

 

I just tested a "brown" 1939 Jefferson nickel with the XRF, VF grade, and it came back well over 84% copper. That is almost 10% more than mint specifications, and not a small enrichment by differential leaching of metals. I am reluctant to publish my findings until I have analyzed a lot more (to have statistical relevance). To date, I have found brown:

- 1908 liberty nickel (~79% Cu)
- 1924 buffalo nickel (~82% Cu)
- 1936 buffalo nickel (~79% Cu)
- 1939 Jefferson nickel (~85% Cu
- 1940 Jefferson nickel (~82% Cu)
- 1953 Jefferson nickel (~78% Cu)

On another forum, a roll hunter who has searched more than 260,000 nickels has a small hoard of those brown coins, saved only because they looked different. Hopefully, I can borrow those for analysis and to speed up the hunt...

Stay tuned.

 

I just wanted to say, as a nickel enthusiast, I think this is an interesting project. I'm looking forward to your findings, so keep posting!

 

Yes I have a 73 Jefferson.

 

Very interesting topic I would like to study, only need a few thousand for an XRF now...


-SC.

 

I have a 1936 buffalo nickel that is solid brown on both sides it doesnt even look like it has silver in it

 

Cool. It actually doesnt have silver in it. 75% copper and 25% nickel. Well possibly more copper for your specimen.

 

How much do these XRF Scanners go for? 1500? Id like one but never knew how much they cost.