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Unusual Coin Find #2

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A couple friends in Louisville invited me down to search a spring on one of their properties.  Louisville (https://en.wikipedia.org/wiki/Louisville,_Kentucky), being on the Ohio River, was one of the earlist settlements in the USA west of the Applalachian Mountains, founded in 1778 by Revolutionary War hero William Rogers Clark, better known as the older brother of William Clark of the Lewis and Clark Expedition which explored the Louisiana Purchase (https://en.wikipedia.org/wiki/Louisiana_Purchase) at the commission of Thomas Jefferson.  It's likely the spring was in existence well before Europeans arrived but how long it has been visited by humans isn't known.  Of course I was hopeful of finding some very old coins and relics.

There is currently a catch pool a few square meters in size.  I didn't know its depth until I carefully stepped into its murky waters.  Fortunately my hip waders were just high enough to keep me dry.  The bottom of the pool had a hard (rock?) floor but a layer of mud and decaying organic matter was next and 30+ cm deep.  I was swinging (more like probing) the Minelab Equinox 800 with both 6" and 11" coils.  Once finding a target I (blindly) felt around with the Garrett Carrot.

Searching the pool was difficult and besides a couple electric lights (unknown to the current owner) I surprisingly got no hits.  I didn't search the entire pool as it was quite difficult to traverse the mud.  I decided to move downstream to a manufactured series of steps (mini-waterfalls).  In the very first one I got a 30 TID and was able to recover the metal disk shown in the photo.


My first thought (make that 'hope') was that I had found a US half cent (first minted in 1793 and last in 1857).  It appeared to be about the correct diameter.  Those were made of pure copper which was consistent with the TID.  I quickly noted how thin it was, but rationalized that was due to wear.  I recall a story my uncle told me from when he was in the Army stationed in Puerto Rico in the early 1950's.  He said that the silver coins circulating there at that time were Barber dimes, quarters, and half dollars and had been worn down to literally half their original thickness.  I imagined half cents getting that much usage....  I could see no detail, but again, heavy wear can do that.

Always skeptical, I wasn't ready to claim victory.  The excitement began to fade when my friend pointed out that the edge was reeded.


I was pretty sure that USA half cents and cents have never been reeded.  As I later found out, reeding was implemented to discourage the unscrupulous from nipping off the edges of coins made with precious metals.  Copper didn't qualify as precious.

When I got home I measured the diameter (~23.9 mm) and thickness (varying between 1.2 and 1.3 mm).  The diameter was just a bit large for half cents (which were minted with three different diameters over their years of production, from 22.0 mm to 23.5 mm).  Weight was 3.38 grams.  The lightbulb eventually turned on in my head.  Equinox TID of 30, appearance of copper, ~1.25 mm thick, and especially telling:  reeded edge,  Can you now see the light?

Here are the nominal size and weight of the pure copper core of a US clad quarter:  24.3 mm diameter, 1.17 mm thickness, 3.78 grams in weight.

What still surprises me is the question: what happened to the cupro-nickel top and bottom layers?  Unlike Zincolns (copper coated zinc pennies) and the 1943 zinc coated steel pennies, the cladding on modern US coins is rather thick and makes up 1/3 of the coin's weight and thickness.  Then I recalled another discovery I had made this fall while hunting one of my local parks:

I chose the oldest looking tree I could find (and it was definitely an old hardwood) and started hunting around its trunk.  I recovered three coins in different locations but all within inches of the trunk, one a US 5 cent piece ('nickel') which was quite discolored (red) and corroded.  I've always thought this was a sign of time in the ground and was hopeful it was an oldie.  Imagine my disappointment when I got home and found it was from the late 1990's.  How did it get so deteriorated?  My hypothesis is that it's the decaying leaves which are more likely to survive (away from lawn mowers) next to the tree's trunk.

Apparently the clad layers of this modern quarter had been attacked by the acid from the decaying leaves in the springs catch pool!  Even moderately dilute acid can eat away metal if you give it a lot of time to soak, and that coin had spent most of its lifetime bathed in acidic water

In one point-of-view, a disappointing find, but another learning experience to compensate.

Postcript:  I did search the land around the spring a bit and found the following advertising pocket knife with readable wording.  I also show a pristine one whose photo I found on the internet.  I really don't know the age but the company was in business from the late 1800's at least through the mid-1960's.  My WAG is that it is from the 1940's or 50's.


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Looks like some the dimes I dug at the beach.

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On 12/17/2019 at 12:08 AM, kac said:

Looks like some the dimes I dug at the beach.


20 hours ago, fredmason said:

In the 50’S and 60’s my grandmother collected coins...we found mercs, barbers, buffs

some were extremely thin.

Always good to hear confirmation that my observations are matched by others.  Of course disagreement/counterarguments are welcome, too, but maybe not quite as satisfying.  😁

In particular I was wondering if others had seen similar, gross deterioration of 25%-nickel 75% copper.  Apparently salt water (which unfortunately attacks even 90% silver) is guilty, too.


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Blackened metal I found is from hydrogen sulfide. It is more common in water that has a lot of rotting matter. Good example is a local pond I fished a ton has some houses around it and they use a fertilizer company to keep those lawns looking like a golf course. In turn that caused massive algae blooms that chocked out much of the natural plant life. I was pulling blackened lead sinkers. No old dimes but the new ones were darkened. With silver Hydrogen Sulfide causes Silver Sulfide (tarnish). On copper it causes Copper Sulfide (patina). Beach coins are subjected to electrolysis which makes them thin especially the alloys like zinc/copper pennies.

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Hi GB,

What I think you have found is a clad quarter which was minted with a poorly bonded planchet. Prior to minting the nickel layers of the sandwich are bonded to the copper layer creating the sandwich. When impurities are present between the layers, the bonding process is ineffective. Sometimes the layers separate prior to coining (stamping the impressions), resulting in a copper colored coin on one or both sides. These types of mint errors are quite rare and valuable. In your case, I believe the bonding was weak and separation of the layers occurred after coining, resulting in a blank copper core planchet.


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