orange coating on silver dollar

turbodog

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While doing estate work... found this. Ideas on the coating? Was this something normal/official? Or it is just something the prior owner put on there and should be cleaned off? There a numerous ones like this.

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ABTOMAT

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That's a fairly modern bullion round, not an actual dollar. Probably not any value over melt. If I had to guess someone may have glued a bunch of them as part of some artistic display that they later were dug out of.
 

chillinn

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Maybe you're reading this on mobile or something, but there's the silver oxidation and then a THICK layer of orange, probably 1/32 to 1/16 think in places.
Toning isn't necessarily thin or thick, and greatly depends on environmental conditions, but mostly what's happening there is the copper mixed in the silver is oxidizing in a reaction to something wherever it was kept. The oxidizing layer starts out orange and eventually will turn to the familiar green patina. It's basically rust, which is when iron oxidizes, but we don't call it rust with silver or copper or any metal mixed with precious metal. But rust is oxidization also, and it can get meters thick given enough time. You can do a flame test on it to prove it. Scrape off a little, pulverize it to increase surface area, wrap it in rolling paper and burn it. If the flame turns green, it's copper. This guy disolves it in an alcohol solution and sprays it on the flame, which is pretty clever. It'll be immediately obvious. There's an image of orange oxidized copper here, which also shows small areas where it is turning green, which is how the whole thing will be eventually.
 
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3_gun

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No harm in cleaning this with water, mild soap & a soft brush, if needed. Easy check to see if it is silver, after cleaning it balance it on a finger tip & lightly tap an edge with something steel. True .999 silver will "ring" with a clean high tone. A fake will make a short flat tone or even a thud. It's not 100% but it's a start
 

chillinn

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No harm in cleaning this with water, mild soap & a soft brush, if needed.
While I don't think this coin is very valuable, most numismatists would advise against cleaning coins, including with soap and water, as it can reduce its collector's value. Collectors want untouched coins. Again, I seriously doubt it matters with this non-circulated non-denominated "coin."
 

3_gun

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There is no collector or numismatists that would care about this coin as there is no way to know the numbers made, weather it was made for X many years or how many "mints" made coins. It's only value is its 1 troy oz weight + .999% purity, if either are really true
 

chillinn

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There is no collector or numismatists that would care about this coin as there is no way to know the numbers made, weather it was made for X many years or how many "mints" made coins.

Right, but it's possible someone at a later time may mistakenly follow the suggestion with another coin when it mattered.

It's only value is its 1 troy oz weight + .999% purity, if either are really true

The amount of copper leaching out of it and the amount of tarnish all but assures it's not, but if it weighs out, it could still have $20 worth of silver in it regardless of the amount of copper.
 
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jtr1962

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Too bad it wasn't a stash of gold coins. I keep hoping to find something like that when I'm digging around doing yard work.
 

nbp

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You may be a lot closer than you realize...

Gives me an idea where to look for more of these. Thanks.
The significant thickness of the red stuff and the fact that it seems concentrated in the crevices makes it look like something stuck on the coin, rather than a tarnish growing on the surface. Tarnish and patina is usually pretty thin and even in my experience.
 

chillinn

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Examples of copper toning, the patina already green. The last two coins are artificially toned, but this is effectively done by speeding up the natural process. Toning, just like rust and other oxidation processes, can be quite crusty and uneven.

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22HfbAW_d.webp

kQEmaoO_d.webp


All that needs done to confirm is to take a needle, scrape off a little, and burn it.
 

onaxis

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Examples of copper toning, the patina already green. The last two coins are artificially toned, but this is effectively done by speeding up the natural process. Toning, just like rust and other oxidation processes, can be quite crusty and uneven.

sPlynK1_d.webp

1jto9Wg_d.webp

qqFzuZB_d.webp

22HfbAW_d.webp

kQEmaoO_d.webp


All that needs done to confirm is to take a needle, scrape off a little, and burn it.
The color of the corrosion is vertagris.
Examples of copper toning, the patina already green. The last two coins are artificially toned, but this is effectively done by speeding up the natural process. Toning, just like rust and other oxidation processes, can be quite crusty and uneven.

sPlynK1_d.webp

1jto9Wg_d.webp

qqFzuZB_d.webp

22HfbAW_d.webp

kQEmaoO_d.webp


All that needs done to confirm is to take a needle, scrape off a little, and burn it.
Examples of copper toning, the patina already green. The last two coins are artificially toned, but this is effectively done by speeding up the natural process. Toning, just like rust and other oxidation processes, can be quite crusty and uneven.

sPlynK1_d.webp

1jto9Wg_d.webp

qqFzuZB_d.webp

22HfbAW_d.webp

kQEmaoO_d.webp


All that needs done to confirm is to take a needle, scrape off a little, and burn it.
The green corrosion is called Verdigris. It's poisonous.
 

chillinn

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The green corrosion is called Verdigris.
Right. It was once orange was my major point, before turning green (see OP's images). Most just call it patina, but that could be on anything, but formally it is called verdigris with copper, from the Middle English vertegrez, from the Old French, verte grez, meaning vert d'aigre, "greened by vinegar." But it's just oxidation of the copper, and even though the coin is silver, this one must have copper in it beyond the ".999 fine silver" claimed on it.

It's poisonous.
And you're right again, eating it would be bad.
 
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SYZYGY

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eh, look at it carefully (incl the thickness and texture and how the surrounding coin material looks in the immediate vicinity). it's almost certainly a foreign substance. oxidation from the coin? no, it looks nothing like that, lol.

OP's in the best position to determine what it is. scrape some off, get it wet, smell it, play with it. do basic qualitative chemistry tests on it. see what it's soluble in (if anything). you could try polar/nonpolar solvent, acid solution, etc. you could also do a flame test both to get an idea of metal ions and to check for thermal decomposition (which would happen if it's polymer).

could be red clay dirt. could be some kind of glue. could be some kind of casting or modeling clay. one more theory: soemone tried to make a mold from it.
 
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chillinn

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look at it carefully (incl the thickness and texture and how the surrounding coin material looks in the immediate vicinity). it's almost certainly a foreign substance. oxidation from the coin? no, it looks nothing like that, lol.


you could also do a flame test both to get an idea of metal ions and to check for thermal decomposition (which would happen if it's polymer).

You can do a flame test on it to prove it. Scrape off a little, pulverize it to increase surface area, wrap it in rolling paper and burn it. If the flame turns green, it's copper. This guy disolves it in an alcohol solution and sprays it on the flame, which is pretty clever. It'll be immediately obvious.

All that needs done to confirm is to take a needle, scrape off a little, and burn it.

What is kind of interesting and somewhat of a theme of this thread and at least a few others, if a CPF member has never seen something before, they just can't believe it.

There are only 25 blimps in the entire world.

The reason the chainsaw was invented was for surgery.

There are only 30 major dialects in the US.

New York City is further south than Rome.

The US has a 1.4B pound surplus of cheese.

Barcode scanners only scan the white areas in the barcode.

There are more trees than there are stars in the Milky Way.

How to make fire with ice.

Are there more McDonald's Restaurants in the US than libraries? Answer to yourself before looking, you're on the honor system.

The thing is, no one knows everything, and few seem to be willing to doubt their own impressions only supported by what they have and have never seen. The first thing we should doubt is our own assumptions.
 
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