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D-Mint Plain Edge Dollar Coins Might Be Told Apart From P-Mint Dollars

By March 11, 2007

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Leading error coins expert Tom DeLorey has given me a statement regarding the possibility that plain edge Denver Washington Dollars might be able to be told apart from the Philadelphia specimens. This is a theory I first proposed back in the last week of February, based on the scores of photos I had seen of plain edge coins that had been sent by my site visitors.

On Wed., March 7, I arranged a meeting between myself, Chicago Ron (who found the Presidential Dollar Plain Edge Discovery Specimen as well as numerous other Denver specimens in the Chicago area,) and error coin expert Tom DeLorey, plus a couple of other top-notch coin experts from leading dealer Harlan J. Berk's staff who joined in. Chicago Ron had acquired 10 Philly plain edge specimens, plus we had one other Philly from another area in Florida. DeLorey examined the specimens we had available (among about 20 Denvers and the 11 Phillys) and concluded tentatively that based on what he could see in the color differences between the coins from each mint, as well as certain edge characteristics, that my theory that we could authenticate the very rare Denver specimens might have some merit.

Despite my jubilant mood (this is, after all, my first big "event" since taking over the About.com Coins Guide role, and one of the first important theories about error coins I had ever dared to utter publicly,) I held off on making any public announcement because Tom also said that despite the evidence in front of him, we had way too few coins, from way too early in the overall distribution process, to make any kind of certain determination at all.

After consulting with other leading experts around the country, DeLorey gave me a statement that pretty much shot down my hopes for being correct based on my original logic. Here is the text of Tom DeLorey's statement:

Statement From Tom DeLorey Regarding Determining the Mint for Plain Edge Washington Dollars

"After talking to other experts, I think that I have to say that my theory that the Denver Mint Plain Edge Presidential Dollars can be identified by the brass coating over the copper core on the edge cannot be proven conclusively.

"It would appear that for now the Denver Mint coins, both regular and plain edge, do consistently come with their edges coated with a film of brass. I suspect that this film of brass is deposited during the planchet burnishing process, wherein the planchets are also coated with some unknown anti-tarnishing agent.

"I do not know what this anti-tarnishing agent is, or if it itself is brass-colored, but it is likely that some of the brass in the cladding layers is becoming rubbed off of the planchets and suspended in the anti-tarnishing solution during the burnishing process, and then redeposited on the edges of the planchets as the anti-tarnishing dries on the coin.

"The Denver Mint coins that I have seen all show this brass coloring on the edge, and Fred Weinberg told me that he had noticed the brass coloring on the edges of normal coins independently of my observations. The Philadelphia coins that I have seen all show the copper core on the edge to some degree, though it is possible that some show a weak brass coating on the edge.

"The problem is, this brass plating of the edges of the planchets is a non-standard result of a newly-introduced manufacturing process, and cannot be relied on. Although many of the Denver Mint coins appear to have been burnished in a solution that was used too long, so that too much brass became suspended in the solution, later Denver coins might be burnished in clean solution.

"Meanwhile, at the Philadelphia Mint, it is impossible to say that at some point they did not use a batch of burnishing/anti-tarnishing solution that had gotten old and full of suspended brass. I have not seen such a coin, but I cannot say it did not happen.

"In conclusion, I have no doubt that Plain Edge Washington Dollars were released by the Denver Mint. I believe that these can be tentatively identified by the solid brass color on the edge, but not provably so. I did saw a normal Denver Mint coin in half to see if I could detect a noticeable thickness to the brass coating on the edge, and could not. This proves, to me at least, that it is just a very thin surface coating, that could be easily duplicated by plating a coin after it left the Mint.

"The only sure way to prove that a plain edge coin came from either mint would be to find a coin struck from the same obverse and reverse dies but with a lettered edge. This might be possible in a roll or original box."
(Emphasis is mine - Susan)

"Tom DeLorey"

I emphasized the last paragraph to draw attention to the fact that although my original theory is probably not going to hold up for the long haul, there might still be a way to authenticate the Denver specimens (meaning I am probably right, but for the wrong reason.) I strongly recommend that anybody who finds a Denver specimen save the entire roll of coins, any other rolls you got with it, and the whole box of 40 rolls if you have them. An expert might be able to find a die match between your plain edge coin and a Denver mint marked normal specimen, and thereby prove that the plain edge coin is from the Denver Mint.

I would again like to express my sincere gratitude to Tom DeLorey for the time and expertise he has so generously shared with me throughout this whole plain edge dollars event. I would also like to thank Fred Weinberg, who has given freely of his time and expertise as well, and who saved me from a horrible faux pas had he not warned me in advance that something I was about to publish was total hogwash. (I had been given information that was just flat out wrong, and I'm glad I double check everything before I publish things!)

I would also like to thank the more than 1,200 site visitors and others who sent error coin reports, information, and photographs. Although I have covered these dollars extensively this past few weeks, there are many more fascinating coins out there to collect, so my normal coverage of general coin collecting topics will resume following this post. I will still post major Presidential Dollar news, as appropriate, and for those who don't want to miss any further Presidential Coin coverage, you can subscribe to an RSS feed for my blog, or join my FREE weekly About Coins newsletter, where I will keep everyone up to date on this remarkable and unprecedented plain edge error, as well as other site updates and important coin news.


March 12, 2007 at 12:58 pm
(1) Kevin says:

Ok, so I’m looking into the rolls I’ve got remaining after my Ebay auctions, and yes… there are some coins that have a 2 tone effect on the edge, I guess it looks brassy. And then some coins that are more sparkeling golden color.

When held together in a stack, you can see the color difference between the coins. So, which is which?? Denver the brighter solid color? Or are they MAYBEE the ones that have the 2 tone washed over effect??

Wondering which ones to hold onto for my private collection.


February 24, 2009 at 1:00 pm
(2) John P. says:

I have noticed that some of the P mint Plain edged Washington dollars were struck with an abraded reverse die west of Liberty’s neck. I have seen these abrasion lines on NGC slabbed examples. If a P Mint dollar with edge devices can be matched with the same abrasions, this should prove a Philadelphia strike on those plain edged dollars.

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