1788 counterfeit NJ copper

[Greylock]

I have found a few nj coppers but this is my first nj counterfeit so I'm pretty excited about that. Rang at a nice mid tone and in the mid 60's on the at pro. wasnt expecting a coin at all but when it came up and I seem the shield I knew it had to be a fake. Also found a few buttons as some iron but the iron goes right into some apple cider vinegar when I get home.

 

[Greylock]

So I took the coin to a scrap coin shop and it weighed 7 grams. A little on the low side but still very interesting

 

[Jyverb64]

Great coin and discussion about it

 

[Steve in PA]

Congrats on a super cool copper!

 

[CASPER-2]

 

[doninbrewster]

Don in SJ. Neither one is a counterfeit. I also have a Nova Eborac that is 78.9 grains and I've seen a Connecticut that was under 70 grains.

 

[doninbrewster]

I forgot to mention I have a 1788 CT M.16.3-N that weighs 71.8 grains and to the best of my knowledge it's the 3rd lightest known CT copper.

 

[Iron Patch]

A lot of fuss made about the weight but I would be much more interested in a tap test which is easy and only takes a minute!

 

[Greylock]

A lot of fuss made about the weight but I would be much more interested in a tap test which is easy and only takes a minute!

I just tried it and it seems to make the same ring as other coppers.

 

[Iron Patch]

I just tried it and it seems to make the same ring as other coppers.

Do you have any coins you know are cast? If you try those you'll see how they thud. I don't think this is by any means a full proof method, but was told to me by someone who wrote a book on counterfeits.

 

[Greylock]

Well I have this KG that I think is cast. The problem is I'm been cutting and splitting wood all day and I can't hear that well right now. Ill have to try it later on.

 

[hogge]

A lot of fuss made about the weight but I would be much more interested in a tap test which is easy and only takes a minute!

Oh....IT RANG OUT QUITE CLEAR WHEN I DROPPED IT ON MY DESK BY MISTAKE, Right in front of Tom. Personally.....I think do not think it's cft. I just think it was struck on a slightly smaller, bad, or odd shaped planchet. The one thing bugging me is that the variety, and strike, fits the smaller planchet. Aren't they supposed to be on a 29mm not 27mm? That would be the difference in weight. But the coin does" ring" out quite clear. Not a dull thud.

 

[Iron Patch]

Oh....IT RANG OUT QUITE CLEAR WHEN I DROPPED IT ON MY DESK BY MISTAKE, Right in front of Tom. Personally.....I think do not think it's cft. I just think it was struck on a slightly smaller, bad, or odd shaped planchet. The one thing bugging me is that the variety, and strike, fits the smaller planchet. Aren't they supposed to be on a 29mm not 27mm? That would be the difference in weight. But the coin does" ring" out quite clear. Not a dull thud.

If you compare you'll see it actually doesn't fit quite as well as a 29mm.

 

[Iron Patch]

...

 

[Greylock]

Definitely different than what I usually pull out but I'm happy with it either way. Thanks for everyone's help

 

[Rick (Nova Scotia)]

Said it before, and can always prove it anytime I want to, but the numbers on a detector will not tell the story. I have a coin that I thought had to be counterfeit because it was dark in color and rings in like a small tombac button. The conductive number should be a 28 on this particular coin, and it rings in at 8! I finally got curious enough to do a scratch test and low and behold the thing is copper and a genuine coin. Have never seen another ring in so low, but don't have to because that's enough proof you can't say a coin is counterfeit just because it rings in a bit lower.

A tap test would tell you more. Balance the coin on your thumb and grab another coin which you know is copper. You then strike down on the edge and it should ring like a bell. If it clunks, it's probably cast.

I couldn't agree more about ID numbers, and here's why, when I first started finding old coppers I was very puzzled why old, larger, heavier copper coins were often a lower ID number than a new, much smaller, lighter copper coin. My theory is that as the copper decomposes, and gets it's green (or other) coating it must change it's conductivity.

There are definitely chemical changes going on, the green stuff is mainly CuCO3, and whether or not this proves my theory, or anything for that matter this is interesting. I took two coins, one not dug, and one dug with an even green coating on it, both same size, and composition, the detector IDed them at 82, and 72 respectively. The ONLY varible was the green coating on the second coin. Next I took an ohm meter and checked them across their width, as expected the clean coin had zero (for practical purposes) resistance, the green coin I could not even get a connection on while pressing the leads hard. So there is definitely less conductivity. I'm sure, (but haven't tested/tried) different types of coatings would give even wider ID ranges. I think personally, I've found coppers from high 80s to low 60s.

Anyone with a detector, a couple of coins, and a 12 dollar multi tester can verify all this. It don't count if after you found the coin you clean all that stuff off.

 

[Iron Patch]

I couldn't agree more about ID numbers, and here's why, when I first started finding old coppers I was very puzzled why old, larger, heavier copper coins were often a lower ID number than a new, much smaller, lighter copper coin. My theory is that as the copper decomposes, and gets it's green (or other) coating it must change it's conductivity.

There are definitely chemical changes going on, the green stuff is mainly CuCO3, and whether or not this proves my theory, or anything for that matter this is interesting. I took two coins, one not dug, and one dug with an even green coating on it, both same size, and composition, the detector IDed them at 82, and 72 respectively. The ONLY varible was the green coating on the second coin. Next I took an ohm meter and checked them across their width, as expected the clean coin had zero (for practical purposes) resistance, the green coin I could not even get a connection on while pressing the leads hard. So there is definitely less conductivity. I'm sure, (but haven't tested/tried) different types of coatings would give even wider ID ranges. I think personally, I've found coppers from high 80s to low 60s.

Anyone with a detector, a couple of coins, and a 12 dollar multi tester can verify all this. It don't count if after you found the coin you clean all that stuff off.

Here's a question on the topic I'm curious about, not that I expect it to be answered. What's the lowest % of copper a coin can have before it loses the dominant color. For example would a 50% copper 50% white metal still look copper, or would it appear to be white metal? The two "coppers" I have that read extremely low are Ships Colonies tokens. They are copper colored as I did a scratch test, but I wonder if the copper is dominant when it comes to color, but another metal is what is bringing the signal down so much. Both are black coins when basically every other ships token I've dug is green and registers high, and I've found at least 20.

 

[Rick (Nova Scotia)]

Here's a question on the topic I'm curious about, not that I expect it to be answered. What's the lowest % of copper a coin can have before it loses the dominant color. For example would a 50% copper 50% white metal still look copper, or would it appear to be white metal? The two "coppers" I have that read extremely low are Ships Colonies tokens. They are copper colored as I did a scratch test, but I wonder if the copper is dominant when it comes to color, but another metal is what is bringing the signal down so much. Both are black coins when basically every other ships token I've dug is green and registers high, and I've found at least 20.

An educated guess is no, an alloy of 50% copper, and 50% white metal would not look copper. As in 18K white gold is 75% gold and only 25% white "stuff" no longer has any gold color at all. What exact percentages would get noticable color changes I would not know, but it may not be all that much. I wonder what the black stuff is. Green, and brown crusts are common, but black sounds more rare.

 

[Iron Patch]

An educated guess is no, an alloy of 50% copper, and 50% white metal would not look copper. As in 18K white gold is 75% gold and only 25% white "stuff" no longer has any gold color at all. What exact percentages would get noticable color changes I would not know, but it may not be all that much. I wonder what the black stuff is. Green, and brown crusts are common, but black sounds more rare.

Yeah I believe it still would look copper but wonder how much white before it changes. Maybe my ships tokens are counterfeit, just look copper because it's still the dominant metal. Given they ring in so low that does sound like the most viable explanation.