Pitting In Silver Coins

[Andy2640]

Just a quick one chaps (Do we have any chapess's) ........anyways, what causes pitting in silver coins.  I found a 1898 coin yesterday and it has micro pitting in it.  Never had that in any coin ive ever found.  Thats why i like silver, cus its always in good condition.  But these pits baffled me.  The soil at this location is generally a mild PH, and very dry sandy soil - which to my mind is great for preservation, but bad on abrasion.  But i have found over 15 silvers here, and none have pitting.   So considering these conditions, what it is that would cause the pitting?

 

I defer to your expertise,

 

Thank you.

[Alluminati]

Is there a chance its a fake coin?

If not I suppose salt etc. could do it.

[Andy2640]

Just now, Alluminati said:

Is there a chance its a fake coin?

Arhhh never considered that, very interesting suggestion.  I dont know.  Got me thinking now.  Never crossed my mind that these old coins im finding could be forgeries. .

[Alluminati]

Its probably real, just the description made it sound like it was cast with poorer metal. Some old coins do have lots of fakes though.

In reality the coin could have spent part of it's life in the water. Even freshwater can pit a coin after 50 or so years, it depends and the coin and more specifically the alloy. A higher alloy sterling silver might pit less then "coin" silver.

[Nig the Dig]

chemical reaction in the soil. lot of acidic fertilisers used and if it's a George the third it's probably low grade silver too.

forgeries tend to be base metal with a silver wash

[Andy2640]

7 hours ago, Nig the Dig said:

chemical reaction in the soil. lot of acidic fertilisers used and if it's a George the third it's probably low grade silver too.

forgeries tend to be base metal with a silver wash

Sorry should of mentioned, its a Late Victorian shilling (so my date might be off, as pitting has partly erased it, and i was going off an online coin site, which may be off too knowing the internet) but it is high grade silver 92.5% sterling silver.  Anything in Britain under 1920 was the same.  Thing is, the other coins which were pre-1920 have no pits and i literally found a few other silvers within 10 metres of it .  As i mention, in my experience, silver tends to preserve very well  but this one....well im scratching my head.  I can be very pedantic, needing to know the hows, whats and why's, very annoying i know, but my brain is my brain, got no other to swap it with unfortunately ?  So i think there is a slim chance it could be a forgery, but a chance non the less, but like you guys say though, the pitting could be caused by a host of other reasons. 

Any metallurgic (EDIT: Metallurgy) experts about, please feel extra free to chime in.

 

Thanks you lot, your awesome.

 

Andy.

[BigSkyGuy]

Hi Andy,

I have found a few silvers with this type of pitting, but not many. My theory on how these may become pitted is as follows;

1. The silver coin reacts with sulfur in the air while at the surface (before burial) to form silver sulfide on the surface of the coin.

2. Following burial, under different pH and/or redox conditions, the silver sulfide dissolves leaving pits.

I have cleaned silver coins with thick silver sulfide spots (using electrolysis) and the coin was left with very similar pits where the silver sulfide was. Coins with uniform thin coatings generally turn out better following cleaning (in my experience).

Just a guess. Congrats on the silver!

Kent

[Randy Dee]

Andy

Your Victoria Shilling is a forgery and the base would be of poor copper then dipped in silver, the shillings and sixpences of George III were more susceptible to being forged than most other reigning sovereign and here below  is a forged George II Shilling in the first stages of deterioration similar to yours.

Over the years I have found many forged coins especially the Bullhead tanners (Sixpence) of George III he was called Bullhead because of his fat large head.

 

Forged George III Shilling

This is the best shilling example with most of the original silvering remaining. It's very convincing now and would have probably been undetectable without scratching the silvering of in 1819! In comparison with a real one it would seem this coin was either struck in inferior metal with the original (stolen) Royal mint dies or copied by a very very talented engraver. The artistic aspects of this coin are parallel with the original and there are no differences whatsoever with the quality and positioning of the design elements. Well done that forger!

[Andy2640]

This is now the 3rd time Randy has come good with expertise that just blow me away!  Thank you.

 

Well......Im actually over the moon i have a unique forgery.  Its something different, and that to me means more than the real thing (which i have a few of anyways).

 

Its getting too much this detecting game, I'm far too happy for my own good these days. 

Once my mortgage is paid off, ill be in heaven on earth ? 

 

Bloody brilliant, thanks all.

 

Andy.

[Alluminati]

That is cool, I think I'd rather have the forged coin as well.