1999S Proof Cent Mint Error?

[Gabev71]

I thought i would post this here instead of the coin section because of all the looks and posts that come up here. Went thru a box of pennies today, mostly because the lack of luck lately on halves. Went thru a roll and there were actually a couple of proofs in it. The one i have a question about is the one pictured. On the reverse side where the memorial is there is a stain of some kind and when held right it looks like most of the copper layer is missing. Is some kind of mint error or just damage from whoever had this penny before.

 

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[Immy]

Waited till I got to work so I could see it on a better computer but I still can't really tell what it is. Is there a slight depression (recessed area) below the steps? If so, it could be a planchet flaw or defect of some kind. Not sure of value. Unusual for a proof coin though because they get more of an inspection than business strike coins.

 

[Gabev71]

there isnt any depression of any kind from what i can tell...just that where the stain is on the memorial and under it the proof shine is still there. almost like the planchet was stained or altered before it got pressed into the proof. and under a magnifier every stair line is there but the copper is missing to the point where zinc is starting to show thru.

 

[Immy]

Ah, I see it now. That may be what's called a sintered planchet. When the coin blanks were heated (annealed) prior to minting some copper dust may have clung to the planchet surface, causing the discoloration that appears to be "under" the design elements. Normally a sintered planchet is much darker though, almost black in fact. But maybe the minting characteristics of proof coins (they're struck twice with highly polished dies) makes it appear lighter. Neat find either way!

 

[Gabev71]

never heard of a sintered planchet before, but gives me a reason when i have time to take it by a coin shop i go to once in awhile. on the 3rd pillar from the left there is a black spot that fades slowly away going to the 2nd pillar could be the darkening u mentioned. guess i'll have to make a trip and find out. thanks for the help Immy, and im jealous u still have casinos that deal with coins.

 

[Immy]

thanks for the help Immy, and im jealous u still have casinos that deal with coins.

You bet!

I'm lucky but I know the days coin slots are numbered, so I'm hittin' 'em hard. One of my fave local spots for nickels just went coinless but it's doubly bad because it was literally a block from my place.

As the pros say, gotta keep pluggin'!

 

[VERMONTPACKRAT]

The coin looks to me to have some "target toning" Sometimes the coins react with the holder they are in and they start to color over time. Do a search for target tone or rainbow tone on ebay. You will see alot of them in various stages of tone.


VPR

 

[GMan00001]

I'm lucky but I know the days coin slots are numbered, so I'm hittin' 'em hard. One of my fave local spots for nickels just went coinless but it's doubly bad because it was literally a block from my place.

Doesn't that mean you need to move downtown where they still use coins...

 

[Immy]

Doesn't that mean you need to move downtown where they still use coins...

No kidding, I was looking at some of the smaller houses in the area and thinking how nice it would be to just walk acoss the street to my penny casino.

Just my luck they'd go coinless the day I close escrow...LOL