Rare 1840 (O) half dollar

https://forums.collectors.com/discussion/898050/originality-toning

Here is an old thread I wrote on PCGS that might help with originality.

You should look for;
Skin and toning are two different things

Layers of ages on consistent planes
Typically the worn areas will be different than protected. On unmolested the protected areas will be lighter. On lightened examples the protected areas will hold their color longer.
Wiping will exspose silver in the open areas and leave grime by the rim

 

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Another example - maybe more appropriate: also w CAC (sent it in myself last month). I suppose it might be silly to assume that CAC folks will only sticker something they think has original surfaces, but it seems clear that they value that. This one is pretty shiny in pictures but much less so in hand.

 

Looks to have original toning but not it's original skin. Soap bath/mineral oil was common practice for generations on old cruddy silver

 

That, sir (Crypto79) is one heck of a great post! I will study it thoroughly and repeatedly. I love your examples and explanations and - it makes sense! Wonderful!

 

Crypto79 - how do you define "skin"? I assume Patina is skin - ? But of course not every coin has patina. So is patina one form of skin perhaps?

 

That is a lovely quarter

 

Skin is dirt, grim and oils left after many years, tone is chemically reactive metals. If you have an old coin and dip it in acetone you will clean all the dirt and oil away but the colored metal will remain. Tone and skin are two different things but they influence each other. Dirt can slow or speed up the toning process

 

Original surfaces on a circulated 100+ year-old silver coin will be an even grey usually with a lighter greay (called "circulation cameo") on the higher points of the devices, like this quarter:



Yes, in circulation, the patina (H2S bonded to the silver to form Ag2S) does wear off, creating a light pale silvery color like on the relatively-modern silver coins you see in the junk bins. However, 200 years of sitting around in a high-sulfur environment (remember: these coins sat through the industrial revolution, where tons of sulfur were pumped into the air every day), so they almost always toned this way.

The "dark residue" you speak of is actually the previous layer of patina. Notice how there is a dark halo around all of the devices. This is sometimes due to grime buildup in the crevaces, but if the fields are significantly lighter, that means the main part of the patina was stripped away (aka cleaning) while leaving the patina in the hard-to-reach areas. A harsh, vigorous cleaning will get rid of the patina in these crevaces, but that is not the case here.

The wild colors on toned AU and Uncirculated coins is caused by a phenomenon called "Thin Film Interference." You can read about it in my article here: http://www.coincommunity.com/forum/topic.asp?TOPIC_ID=186193

Note that coins that grade less than AU-55 should not have rainbow toning with the exception of residual luster in grades as low as VF-35. These can be discerned by color appearing very tightly around the devices. I'll upload a couple pictures of coins like this shortly.

In terms of detecting a cleaned coin, the "look" is not at all subjective. It is a matter of fact that is repeated very consistently delending on the coin's history. The glossiness comes from an attempt to shine up the metal. Wear from circulation and a thick (>1000nm) patina will greatly dull the surface of a coin. When this patina is removed and some friction is used to "polish up" the coin a bit, the surfaces get a little bit of an unnatural shine for the grade. There is a large difference in the appearance of the OP coin and the Bust Dollar. Look at the two side-by-side and note the differences.

That being said, the Bust Dollar has also had a cleaning, though it was much older and less abrasive than the one the half had. Compare it to my quarter. Notice the paleness to the surface. If left alone for 200 years, it would look like my quarter. However, when cleaned, the surface resets itself and begins retoning. This coin has been retoning for a very long time, and it looks attractive, even if it is not 100% original. Look through a bin of "junk" 90% quarters and halves and you'll see coins in various stages of the retoning process after being taken from circulation.

That quarter is perfectly original. You say it isn't shiny in hand. That is the look you should go for in an EF 100+ year-old coin.

Every coin has a patina (with the exception of many gold coins due to the lack of reactivity of gold), with some having a thicker layer than others. There is also the dirt and grime aspect as well, as @crypto79 points out.

 

Here are a couple examples of what I am talking about. Notice how the luster in the protected areas seems to POP out. Also notice how the colorful toning abruptly ends when the luster ends.



Here is an example of a coin that was cleaned and retoned. Notice how the colored areas seem flat and don't have an abrupt stop. They just gently fade away. Almost all retoned (with colorful toning) cleaned coins apprear this way. Also notice the pale, slightly-glossy fields this coin has that the above capped bust half does not.

 

Thank you, typecoin971973. I super appreciate the information and the examples. Wow. Terrific learning day for me!

And I love your article on toning - hard to follow the science and graphing part without a considerable amount of focus - but the narrative/explanation and conclusion act like an executive summary - seems like great way to distinguish artificial toning from natural in an objective way - could a computer be set up do that? Maybe you addressed that and I certainly could have missed it.

thanks, again.

 

crypto79, posted: https://forums.collectors.com/discussion/898050/originality-toning Here is an old thread I wrote on PCGS that might help with originality.

Thanks, cannot wait to read it!

You should look for;
Skin and toning are two different things.

Very well said. It's an important distinction and I shall steal it.

Layers of ages on consistent planes
Typically the worn areas will be different than protected. On unmolested the protected areas will be lighter. On lightened examples the protected areas will hold their color longer.
Wiping will exspose silver in the open areas and leave grime by the rim.

I need some clarification on this please. The layer concept is important as wear changes color of the surface. The 1813 Half dollar in the post above provides an excellent example. What I always thought is shown on the half: On unmolested coins, the protected areas will be darker.

 

I have the same question! Is it perhaps dependent on the definition of "darker"?

 

I wouldn't swear that the 1813 is perfectly original. Typically colorful cirs have had a soap or acetone bath and the recently raw/exposed silver becomes reactive and colorful. Esp when stored in methods prevalent before flips and slabs. That said it is the current market perferred look which is another point that true originality does not necessarily equal eye appealing. If fact it often doesn't.

 

Could you be more clear about the color of the surface? Let's leave the Capped Bust Half dollar out of it as all the colors seem to have confused the issue I raised above: "On unmolested coins, the protected areas will be darker."

Again, wear changes the color of a natural surface that over time has become dark - often shades of gray. In my limited experience, far below yours, when a naturally dark silver coin becomes worn, the gray surface becomes lighter; yet stays dark (darker) in the protected areas. Thus, my experience is directly opposite yours . Please help!

 

I asked this question above:

"Could you be more clear about the color of the surface? Let's leave the Capped Bust Half dollar out of it as all the colors seem to have confused the issue I raised above: "On unmolested coins, the protected areas will be darker."

Again, wear changes the color of a natural surface that over time has become dark - often shades of gray. In my limited experience, far below yours, when a naturally dark silver coin becomes worn, the gray surface becomes lighter; yet stays dark (darker) in the protected areas. Thus, my experience is directly opposite yours . Please help!"

Thanks for getting me to think it out. If a coin is dirty or darkly toned, any original surface where the dirt or toning did not reach (protected area) may have some remaining luster that will make that part of the coin, next to the relief, lighter.

 

Updated picture of OP coin. Better in hand than in the pictures. This picture is a bit more in focus. I think there might be a chance of passing CAC muster. I may send it in sometime - when I have a few worth submitting together. Based on the information I could find in on-line Gobrecht Journals I think this is the earliest and most relatively common of two die marriages (WB-101?) for this rare New Orleans issue . Thanks for all the discussion and info about originality, etc.

 

Nice new photo...now I'm on the side of the members who posted: not original, old cleaning.

 

Yeah, I think that's it. Not too bad!