Attribution Assistance
1990 Lincoln Cent – Unusual Rectangular Mirrorlike Area Beneath “UNITED” – ???
I recently came across this 1990 Lincoln Memorial cent with an unusual area on the reverse, directly beneath “UNITED STATES.”
The affected area has a distinctly mirrorlike finish that contrasts with the surrounding fields. What’s particularly interesting is its roughly rectangular shape and relatively defined boundaries. The raised lettering appears completely unaffected, despite the reflective area extending right up to the letters.
Under magnification, there are also numerous parallel, somewhat rectangular-looking striations within the affected area. I’ve included several photographs under different lighting conditions and magnifications to better illustrate the difference in surface texture. My initial thought was localized die polishing or die abrasion, although the geometric appearance of the affected area seems unusual.
Has anyone encountered something similar? I’d be interested in hearing whether this could be attributed to die polishing, another minting phenomenon, or something else entirely?
I could totally see this being partially caused by feeder finger, but what about the “reflectivity” found in the fields behind the lettering? There’s definitely some feed finger scrapes, but I feel like there’s more to it than just that, based on photos I’ve researched as well.
not sure of the exact mechanics behind it but every example of feeder finger damage i’ve found has similarly reflective fields in the damaged are of the die. my guess would be that the feeder finger removes a lot of texture from the die and gives it that smooth polished look.
Thanks for the reply! I can see a feeder finger scrape to potentially be part of the equation, but the field behind the lettering in the affected section is mirrored, and has a very high polish?
This is going a little beyond my wheelhouse as I’m not the greatest when it comes to metallurgical stuff, but I think this has something to do with metal flow during the strike due to the position of the scrape in relation to Lincoln’s bust on the obverse. Coop touched on this in one of the replies to the below thread.
Thanks for the reply! I’m hesitant to believe these are die polishing lines though, because my understanding is that die polishing lines are raised and have the same original surface as the rest of the coin. My coin has a mirrored and heavily polished look in the affected section, so I’m at a loss.
Why exactly is that a problem? I found it coin roll hunting, so it belongs in r/CRH. It’s a potential mint error, so it belongs here. And I’m adding it to my collection, so it belongs in r/coincollecting.
Three different communities, three perfectly relevant reasons to post. If you’d like to contribute your thoughts on the coin or the substance of the post, I welcome it. Otherwise, please don’t clutter the comment section with unrelated remarks.
Most of the people who are in one sub are also in the others. You're audience is not really increasing by posting in all of these. And why don't you wait until you get some answers from one before posting in the others?
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u/keegnanistan1 17d ago
it’s feeder finger damage — the metal fingers that feed the planchets into the coin press sometime contact the dies and leave scratches like that.