How to know when your silver coins have been Dipped?

TaylorMade

Years ago I purchased many UNC silver mexican Peso's and 50 Centavos while living in Ca. My question is, How can you know if your coins have been previously dipped, and if so will pcgs slab the coin?

JCMhouston

Generally the TPG's don't care if a coin has been properly dipped, now if the coin has sat in a dp solution long enough to etch the surface that is another matter. You can't really "know", unless you dipped it yourself, however if you have 100 year old coins that are blast white, then it is likely (or whatever term you prefer) that they have been dipped at some point. It is of course possible for 100 year old coins to be completely white if the storage conditions over the years were just right, I just don't personally think it is all that common.

As an example I have had a bunch of British Trade Dollars ranging from 1898-1930 where the majority of them were white with no signs of toning even on the rims, my personal belief is that they had probably been dipped. But the dipping had been done right and the surfaces did not show it, except that they were white, and they were all PCGS/NGC graded.

Lancastercoin

Many coins that were bag stored in quantity (Morgans, Brit T$, post-1920 Mexican silver, year 23 restrike China dollars, 1898 Mo Mexico peso restrikes, the list goes on) have large populations that are naturally white or nearly white. But JCM is right, properly dipped MS/PF 60+ coins can't generally be identified as such until they start to retone.

JCMhouston

Aaron, I agree with you that there are some all white coins to be had. But I remember back in the 70's when I started collecting a lot of dealers were doing a lot of dipping because all white coins were the in thing. And yes, I witnessed a lot of the dipping at my favorite dealers. They didn't even bother to evalute whether it was attactive or not, everything went in their little dip tank. I was a newbie at the time and really didn't know what it was all about but he explained that's what all the dealers did.

MacCrimmon

If you have access to a SEM (scanning electron microscope), you can tell even the most minute "flash-dip" as it will etch (or flatten) the peaks of the coin known as radials. Alas, the last time I had one to "play" with was about 1977 when I was engaged in analysis of Miller Indices for experimental silicon wafers. OMG, I'm getting too old.


Here's the SEM/Swiatek reference to dipping. I believe the Numismatist (or maybe Coin World) published the SEM photos at that time.

folderholder

Very nice website and collection JCM. I enjoyed reading your comments, too.
Best wishes,
Peter Anthony
www.pandacollector.com

Lancastercoin

Mac, I forgot about SEM when I added "generally" but was thinking that a very accurate XRF spectra of the surface would probably show a much higher surface silver content on a dipped silver coin than an undipped. You think so, or am I wrong here?

wybrit

Alas, the last time I had one to "play" with was about 1977 when I was engaged in analysis of Miller Indices for experimental silicon wafers.

Back when you were a mere lad of 60. Didn't know they had SEMs back in those old days! Of course, once the Guilford Courthouse collection is sold, you could buy one with cash!

a very accurate XRF spectra of the surface would probably show a much higher surface silver content on a dipped silver coin than an undipped. You think so, or am I wrong here?

More than likely. There might be a lower O content in a dipped coin as well, but O is so prevalent that maybe not...

canadacolornut

I think I know the answer to this but asking it anyway in case someone has come up with a solution.

Is there any way at all to remove spotting from a uncirculated, proof like or proof penny without damaging
it or changing the color?


Thanks for any responses.....

Lancastercoin

<< <i>I think I know the answer to this but asking it anyway in case someone has come up with a solution.

Is there any way at all to remove spotting from a uncirculated, proof like or proof penny without damaging
it or changing the color?


Thanks for any responses..... >>



Changing the color - not to my knowledge
Damaging it - define damage; strip and retone might or might not depending on a lot of things. EAC guys on the US board know volumes on the answers to that question.

7Jaguars

wow, mac, too bad to see the "Bertie" florin to go and wish I had the money for it...

docday2003

<< <i>wow, mac, too bad to see the "Bertie" florin to go and wish I had the money for it... >>



what do you think about the estimate for what they think it will sell for?