Blue Toned Jefferson Nickels Explained?

[WoodenJefferson]

My contentions and suspicions that highly colored bluish proof Jefferson nickels arise from the amount of cobalt contained within the nickel-copper alloy. The basic nickel itself that is alloyed into the copper does attribute to the green color spectrum, whereas the copper yields the reddish-orange colors because copper reflects red and orange light and absorbs other frequencies in the visible spectrum.

There are many proof specimens that have a mixture of these colors blue, green, red on the obverses and reverses but not all proof nickels acquire natural color tones. I believe it's the basic metal alloys that were delivered to the US Mint smelters that will determine the amount of color a proof Jefferson eventually takes on.

 

Nickel is used in many industrial and consumer products, including stainless steel, magnets, coinage, and special alloys. It is also used for plating and as a green tint in glass. Nickel is pre-eminently an alloy metal, and its chief use is in the nickel steels and nickel cast irons, of which there are innumerable varieties. It is also widely used for many other alloys, such as nickel brasses and bronzes, and alloys with copper, chromium, aluminum, lead, cobalt, silver, and gold.

 

Because of its permanence in air and its inertness to oxidation, nickel is used in coins, for plating iron, brass, etc., for chemical apparatus, and in certain alloys, such as German silver. It is magnetic, and is very frequently accompanied by cobalt, both being found in meteoric iron. It is chiefly valuable for the alloys it forms, especially many super alloys, and particularly stainless steel.

 

Nickel is one of the five ferromagnetic elements. However, the U.S. "nickel" coin is not magnetic, because it actually is mostly (75%) copper. The Canadian nickel minted at various periods between 1922-81 was 99.9% nickel, and these are magnetic.

 

Cobalt is not found as a native metal but generally found in the form of ores. Cobalt is usually not mined alone, and tends to be produced as a by-product of nickel and copper mining activities. The main ores of cobalt are cobaltite, erythrite, glaucodot, and skutterudite.

 

In 2005, the Democratic Republic of the Congo was the top producer of cobalt with almost 40% world share followed by Canada, Zambia, Russia, Brazil and Cuba, reports the British Geological Survey.

 

A small collection of Bristol Blue decorative glassware, hand blown in Bristol, England.

Photographed by Adrian Pingstone in March 2004 and released to the public domain.

The intense blue color is due to the occurrence of Cobalt.

 

Of course the all important method of storage comes into play with toned and highly toned Jefferson nickels, including temperature and humidity. But, I have seen on occasion where two different years were kept together under the same conditions, one toned and the other one did not tone at all, hard to explain.

 

I know this is only theory and speculation in layman‘s terms, but something is going on here that can be explained through physics and chemistry, your basic ingredients for change.

 

Note:

1.some years where colored Proof Nickels were prevalent: 1960-64, 1971-74

2.excludes the Wartime Silver Alloy nickels from 1942-45

3.Some business strike Jefferson Nickels take on the hues described but are not as vibrant as the proofs.

4.Of course, artificially toned Jefferson’s attempt to emulate what nature can give us but fail in comparison.

5.I did not know some Canadian nickels were magnetic

 

 

 

[MikeInFL]

WJ, Thank you for your post. Very thought provoking! Would you please explain the following in more detail? I'm not sure I follow your logic:

 

My contentions and suspicions that highly colored bluish proof Jefferson nickels arise from the amount of cobalt contained within the nickel-copper alloy. The basic nickel itself that is alloyed into the copper does attribute to the green color spectrum, whereas the copper yields the reddish-orange colors because copper reflects red and orange light and absorbs other frequencies in the visible spectrum.

I was under the impression that the color of toning had to do with thickness of the thin film of patina (sulfides) on the surface of coin, and not the actual metal per-se.

 

Thanks...Mike

 

[MikeInFL]

FWIW, I have noticed that blue (and yellow) are the most common colors for Buffalo and Jefferson nickels to tone. The coin below is very typical (please excuse the scratched slab):

 

 

Occasionally you also see cherry red and green, as you can barely see in the toned business strike Jefferson below:

 

 

Have fun...Mike

[WoodenJefferson]

WJ, Thank you for your post. Very thought provoking! Would you please explain the following in more detail? I'm not sure I follow your logic:

 

My contentions and suspicions that highly colored bluish proof Jefferson nickels arise from the amount of cobalt contained within the nickel-copper alloy. The basic nickel itself that is alloyed into the copper does attribute to the green color spectrum, whereas the copper yields the reddish-orange colors because copper reflects red and orange light and absorbs other frequencies in the visible spectrum.

I was under the impression that the color of toning had to do with thickness of the thin film of patina (sulfides) on the surface of coin, and not the actual metal per-se.

 

Thanks...Mike

It is a difficult task to relate what you mean to say in precise words and explanations are sometimes more confusing, but here goes..

 

Even though the mint explains that a Jefferson nickel is comprised of .250 nickel and .750 copper they do not list the impurities like cobalt. I would not consider cobalt an impurity but a natural occurring element in the alloys the mint uses to coin the Jefferson nickel series. Cobalt ions appear blue in the color spectrum, the more cobalt, the more intense the blue color will become.

 

The other metals used in the alloy contribute their own spectrum colors. Copper yields reddish-orange and nickel transmits the green hues. These colors will either change and blend together or prevail one another into one intense color pattern.

 

These metals contribute their own light refracting hues that you see on the surface of a toned Jefferson nickel as opposed to other toned coinage such as copper or silver.

 

Did that help?

 

edit:I was under the impression that the color of toning had to do with thickness of the thin film of patina (sulfides) on the surface of coin, and not the actual metal per-se.

 

100% true but the sulfides arose from the alloys held within the coin, a much varying reaction to oxides, temperature and moisture. Hence the varying colors you actually see in our coinage.

 

[MikeInFL]

Thank you for the explanation. However, I'm not sure I agree.

[physics-fan3.14]

Interesting theory. Not sure I subscribe just yet, but it is a good starting place for someone to do some research. Thanks for the well thought out and original post!

[rrantique]

Thank for a most interesting post Woody. (thumbs u

 

BTW some beautiful toned nickels.

[RWB]

Begs the questions: "Has anyone measured the composition of five-cent coins and if so what are the results? Has this been done for pieces of different dates? Can the suppliers of Cu-Ni coin blanks be connected with specific alloy compositions?

[TomB]

I don't agree with the premise of your post. However, many AT nickels from the 1960-1964 range have found themselves in PCGS holders and these are incredibly deep blue and purple, so folks should exclude them from your discussion.

[James_OldeTowne]

FWIW, I have noticed that blue (and yellow) are the most common colors for Buffalo and Jefferson nickels to tone.

I have found that in Dansco albums, yellow is far and away the predominant color for typical Jefferson nickels, with green being the next most common. Older Whitman albums tend to cause a whole spectrum of colors.

[WoodenJefferson]

Thanks for all the comments pro, indifferent or con. The intention of the original post was meant to intrigue as well as an attempt to perhaps explain why some Jefferson Nickels take on such vibrant colors, while others do not.

 

If someone can explain in better terms or has their own postulation please add on to this thread.

[Zoins]

I don't agree with the premise of your post. However, many AT nickels from the 1960-1964 range have found themselves in PCGS holders and these are incredibly deep blue and purple, so folks should exclude them from your discussion.

Have these been exposed as AT? Are there also very blue ones in that date range that are not AT?

[BillJones]

I once had a "cull" Jefferson nickel in a 1962 or '63 Proof set that had turned deep blue. I was a bit of dealer at the time (mid 1970s), and I decided to break the set to sell it. When I cut open the plastic film, a sharp smelling gas escaped from the pocket where that nickel had been held. I think that some sort of sealer that had been used to close the package caused the blue toning to happen.

 

Like I said, back then such a coin was a "cull." Today people flock to buy it.

[Zoins]

I followed a PCGS blue one a while back that eventually sold for $180. I was interested to get one to satisfy my curiosity but more than a few people wanted it more than I did. I heard that they sold for a lot more earlier as well.