Hi all, I'm new to coin collecting. I got a cheap usb microscope and have been going through a jar of pennies. I came across this and the closest description for this I can find online is split plating. Is that what's causing this? Is it common? I came across this in a couple of 1990 and a 1989 penny. Thanks for any help!
You're correct, it's split plating. As the coin is struck, the metal flows into the Letters and devices. The copper plating is about 8 microns (0.0003") thick, so it can get stretched and split. This is more common on coins from the 80's. Over time, the mint improved their process and it's less common now. It's considered damage. You can see the corrosion starting on the exposed zinc in your second pic.
Great, thanks guys. Even if it's a spender I think I'll hold onto them. My first damaged (at the mint) coin find
What you consider to be damage is a vary curious effect of the minting process. Therefore, coin's as this are straight graded as it is not considered to be damage.
Well, it's an error but if you saved all of them you come across you'd have a pile of rotten zombie zincoln after a while. I think.. I don't know I don't keep 'em!
Oh hey, speaking of this and hijacking my own thread, I've found what I'm going to call my first zombie coin as well.
I keep extreme examples of split plating myself, perhaps they don' t have a market or collector value, But I collect it,,, to an extent... he's my pride and joy split plater! Just saying you aren't crazy to hang on to it if you like, it cost ya one cent!
Plate splitting on current copper plated cents is a bane of the collector, in my opinion. This is why I seldom even bother to look at cents with dates after 1982. Just my thing I guess.
yeah I assume so! hahaha. No idea if it's wear on the obverse or something else going on, this coin is all kinds of funky, the L in liberty is almost gone, the 0 is week in the date, and there's like almost a sanding appearance on that side on and near lincoln, I didn't find it in 1990 though, it was more like 1992-93, so that stuff might be post minting damage, but this is the most split plating I've ever seen on one coin so I hang on to it as a curiosity. makes me think something wasn't right on this strike. Think it will straight grade? Maybe MS66? LOL!
Thanks Sal. Hmm, yeah, that example does show deterioration, doesn't it. Evan's right, I'll probably look back on this coin in a few years and find a nice disc of corrosion.
Not really, like I said, I've had mine for,,, jeesh, must be nearing 30 years. the key to longevity with exposed zinc, is to keep it dry and leave it alone as much as possible, the exposed zinc will crust over the top layer a fine dust of zinc oxide and that's it and stop, but every time it's wet or rubbed, banged or knocked off, it will sacrifice more zinc to zinc oxide in order to protect the rest of the exposed zinc. it's why they don't last long in circulation. the zinc oxide keeps getting knocked off as soon as it forms day in and day out. simply putting it in a 2x2 or coin flip or capsule and keep it dry and it will not corrode further. Mine hasn't. I expect my 1990 will be around long after I'm gone or until someone stops protecting it from circulation and sets it free on the world again. scientifically, "zinc rot" is galvanic corrosion. you got zinc, and you have copper, two dissimilar metals on top of each other and in contact. add some moisture or water and the water becomes an electrolyte and you have a galvanic cell and a reaction between it causing rapid corrosion. Remove the electrolyte and no reaction, instead the exposed zinc sacrifices a fine surface layer to protect the exposed zinc and stops until that layer gets knocked off, or water is introduced to start the reaction. In Sals link, the corrosion on the D is due to this galvanic reaction from water/moisture exposure. a sweaty hand, a drop of sweat, someone let it sit in a cup holder and put a cold can on top of it,,, who knows, but no moisture, no Hydrozincite crystal formation. just a light layer of zinc oxide. Zincite is the mineral form of zinc oxide, Hydrozincite is zincite with water as the name implies. SCIENCY!
I seem to find split plating more evident on coins from worn dies where a ridge ring begins to form. Though this can be found most anywhere else also.