Why does some silver not tarnish?

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Cantiaci
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Why does some silver not tarnish?

Post by Cantiaci » Fri Aug 31, 2018 11:57 am

Hi all, just wondering why most silver finds are heavily tarnished but a few silver finds of mine have come out tarnish free?
It may be an obvious reason but always willing to learn👍


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Re: Why does some silver not tarnish?

Post by oldartefact » Fri Aug 31, 2018 12:08 pm

thats a brilliant question ... but dont know the answer.
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Re: Why does some silver not tarnish?

Post by Sir Upanotch » Fri Aug 31, 2018 12:10 pm

Down to the silver content, normally the older the purer, but not always.
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Re: Why does some silver not tarnish?

Post by Shaneb3 » Fri Aug 31, 2018 12:16 pm

Maybe ground conditions? I'm not 100% but I've noticed a difference at my permission with coppers. Out in the open every copper coin of any date I have found has some form of bronze disease or is completely blank. The one time I went into the wooded area I found a few victorian coppers in immaculate condition. I figured the soil was a lot looser and free draining compared to the heavy clay of the open areas.

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Re: Why does some silver not tarnish?

Post by f8met » Fri Aug 31, 2018 12:32 pm

The alloy of the silver makes a difference. My avatar is just as it came out of the ground so there must be a difference in the silver purity. That is also why a lot of the early saxon are so brittle and I have a sterling imitation which is shiny but also brittle.

Soil can also have an effect and it is noticeable from the purse loss of pennies I have that some are shinier than others and you can see where 2 have laid on each other.
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Re: Why does some silver not tarnish?

Post by Cantiaci » Fri Aug 31, 2018 12:57 pm

Thanks for the replies chaps! One of my finds I assumed was aluminium and dropped last year but it’s certainly silver thus the question. The few silver coins I’ve found there have all been tarnished to a point although one Roman silver the tarnish just rubbed off lightly using my thumb.
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Re: Why does some silver not tarnish?

Post by ScoopyDoo » Fri Aug 31, 2018 4:52 pm

Regarding modern silver, which will probably mostly be of interest to beach detectorists, any jewellery with a makers mark and/or a 925 stamp, is likely to have a low silver content or could possibly be electro plate. What you really want to see is a makers mark and a full set of hallmarks which includes an assay office mark.

I've found loads of 925 stamped jewellery at the beach, and it almost always turns up looking severely blackened, unless it's a very recent loss.

I'm yet to find any high quality fully hallmarked silver at the beach, so I would be interested to know how it fares in salt water.
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Re: Why does some silver not tarnish?

Post by Swany » Fri Aug 31, 2018 5:07 pm

I think soil conditions. Found a David II groat that came out nice and shiny from sandy soil. Other coins even Viccy milled from clay soil are always tarnished.
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Re: Why does some silver not tarnish?

Post by slowsweep » Fri Aug 31, 2018 5:26 pm

ScoopyDoo wrote:
Fri Aug 31, 2018 4:52 pm


I've found loads of 925 stamped jewellery at the beach, and it almost always turns up looking severely blackened, unless it's a very recent loss.

I'm yet to find any high quality fully hallmarked silver at the beach, so I would be interested to know how it fares in salt water.
925 is the British standard for silver, all modern silver is stamped either "925" or "Stirling" there is no higher quality only pure silver and that is too soft to be used for any real purpose,

tarnish and oxidisation all comes down to what alloy is used to harden/strengthen the silver and the ground conditions that its been laying in for X amount of years.
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Re: Why does some silver not tarnish?

Post by fred » Fri Aug 31, 2018 5:31 pm

ScoopyDoo wrote:
Fri Aug 31, 2018 4:52 pm
Regarding modern silver, which will probably mostly be of interest to beach detectorists, any jewellery with a makers mark and/or a 925 stamp, is likely to have a low silver content or could possibly be electro plate. What you really want to see is a makers mark and a full set of hallmarks which includes an assay office mark.

I've found loads of 925 stamped jewellery at the beach, and it almost always turns up looking severely blackened, unless it's a very recent loss.

I'm yet to find any high quality fully hallmarked silver at the beach, so I would be interested to know how it fares in salt water.
I acid test most of my beach silver and it is almost always OK whether it is marked 925, hallmarked or even unmarked. You do occasionally get foreign silver with odd marks like 800 and 830 but it's still legitimate as those are standards in some countries. If it's sterling silver it all comes out looking the same. The only real variable on beaches are whether it's in the wet or the dry sand and how long it's been there.

On land it seems to mostly depends upon the soil conditions. ::g
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Re: Why does some silver not tarnish?

Post by fred » Fri Aug 31, 2018 5:36 pm

slowsweep wrote:
Fri Aug 31, 2018 5:26 pm
ScoopyDoo wrote:
Fri Aug 31, 2018 4:52 pm

925 is the British standard for silver, all modern silver is stamped either "925" or "Stirling" there is no higher quality only pure silver and that is too soft to be used for any real purpose,

tarnish and oxidisation all comes down to what alloy is used to harden/strengthen the silver and the ground conditions that its been laying in for X amount of years.
Actually there is still the 958 Britannia Standard which has been available for use in the UK since 1697. The hallmark is a seated Britannia rather than the lion. Not that common but still sometimes encountered. :D
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Re: Why does some silver not tarnish?

Post by Koala » Fri Aug 31, 2018 5:55 pm

I have dug both a roman and Henry VII that have been shiny like the day they were dropped. However they soon turned black once dug, handled and oxygen has gotten to them.


Same with silver plated livery/military buttons.



As a side note I have a few bits of silver that doesn't pass the spit and foil test including a Victorian 4 pence which hasn't gone black.

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Re: Why does some silver not tarnish?

Post by chrisbham » Fri Aug 31, 2018 6:52 pm

That's a very good question and it seems no real answer gives all the info. I have found several silvers (as in medieval) of the same date on the same field within a few feet and one would be grotty and worn flat and one would be pristine. Perhaps one would have previously been deeper with different soil conditions and since raised to the surface through ploughing, but I think it could also be to do with the condition when it went into the ground. If one had greasy fingers or oily residue when dropped and one was clean then surely that would have a difference over a century or millennia in the ground.

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Re: Why does some silver not tarnish?

Post by slowsweep » Fri Aug 31, 2018 9:45 pm

fred wrote:
Fri Aug 31, 2018 5:36 pm
slowsweep wrote:
Fri Aug 31, 2018 5:26 pm
ScoopyDoo wrote:
Fri Aug 31, 2018 4:52 pm

925 is the British standard for silver, all modern silver is stamped either "925" or "Stirling" there is no higher quality only pure silver and that is too soft to be used for any real purpose,

tarnish and oxidisation all comes down to what alloy is used to harden/strengthen the silver and the ground conditions that its been laying in for X amount of years.
Actually there is still the 958 Britannia Standard which has been available for use in the UK since 1697. The hallmark is a seated Britannia rather than the lion. Not that common but still sometimes encountered. :D
sometimes encountered where exactly ? :-/
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Re: Why does some silver not tarnish?

Post by sweepstick47 » Fri Aug 31, 2018 10:14 pm

u;@ Under Fred's search coil presumably :D ss47
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Re: Why does some silver not tarnish?

Post by littleboot » Fri Aug 31, 2018 10:31 pm

I know of Britannia standard but was under the impression it was more or less obsolete these days.
Sterling silver 925 is not 'low grade' but very much the norm. I get quite a lot of silver coins here in France which are 900 or less. 900 is pretty much standard but low-grade 'silver' (less than half silver and known as Billon) was normal for smaller denomination coins and it does make them very brittle. I know this to my cost. They are very brittle when first out of the ground and very prone to fracturing so now I immediately swaddle them up in cotton-wool. (I have found that after a few weeks in their new environment they seem to firm up again and become much less prone to break. I don't attempt to touch them or clean them before then otherwise I end up with a mini jigsaw puzzle instead of a coin.)

I had a couple of belting early 19th century milled 5 franc pieces that came out of the ground tarnished. But it was simply surface blacking and a simple wipe with the ball of my thumb made them as clean as the day they were minted....well almost. A couple of very big milled 18th century silvers (ecus) from a couple of hundred yards away came out clean as a whistle tarnish-wise....just a bit of coil in the detail. Yet on paper the standard of silver was no different...if anything the 19th century stuff was better. I think its down to dampness in the soil,....the blackened ones were in damper ground.
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Re: Why does some silver not tarnish?

Post by fred » Fri Aug 31, 2018 10:34 pm

[quote=slowsweep post_id=925087 time=1535748320

Actually there is still the 958 Britannia Standard which has been available for use in the UK since 1697. The hallmark is a seated Britannia rather than the lion. Not that common but still sometimes encountered. :D
[/quote]

sometimes encountered where exactly ? :-/
[/quote]

Anything at all silver hallmarked in Britain between 1697 and 1720 for a start. This would include items like cutlery which could be found with a detector. ::g

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Re: Why does some silver not tarnish?

Post by Ricky p » Thu Dec 13, 2018 11:18 am

its because of the purity of the material used to make SILVER OR GOLD items,
(IE not made with copper or other base metals)that oxidise in the ground.

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Re: Why does some silver not tarnish?

Post by slowsweep » Thu Dec 13, 2018 12:36 pm

fred wrote:
Fri Aug 31, 2018 10:34 pm
[quote=slowsweep post_id=925087 time=1535748320

Actually there is still the 958 Britannia Standard which has been available for use in the UK since 1697. The hallmark is a seated Britannia rather than the lion. Not that common but still sometimes encountered. :D
sometimes encountered where exactly ? :-/
[/quote]

Anything at all silver hallmarked in Britain between 1697 and 1720 for a start. This would include items like cutlery which could be found with a detector. ::g

https://www.antiquesilverspoons.co.uk/p ... spoon.html
[/quote]
Read my post, all "Modern" silver 8-|
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Re: Why does some silver not tarnish?

Post by Easylife » Thu Dec 13, 2018 7:17 pm

925 = 92.5% silver by weight, same as 900 = 90.0% and 800 = 80.0%.
For example 925 (92.5%) silver also contains 7.5% other metals which could be zinc, copper etc.
So the degree of tarnishing is due to the metal combination and environment it is in.
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Re: Why does some silver not tarnish?

Post by Koala » Thu Dec 13, 2018 9:13 pm

some silver is platted with rhodium until it wears off it will never tarnish ?

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Re: Why does some silver not tarnish?

Post by fred » Thu Dec 13, 2018 9:29 pm

slowsweep wrote:
Thu Dec 13, 2018 12:36 pm
fred wrote:
Fri Aug 31, 2018 10:34 pm
[quote=slowsweep post_id=925087 time=1535748320

Actually there is still the 958 Britannia Standard which has been available for use in the UK since 1697. The hallmark is a seated Britannia rather than the lion. Not that common but still sometimes encountered. :D
sometimes encountered where exactly ? :-/
Anything at all silver hallmarked in Britain between 1697 and 1720 for a start. This would include items like cutlery which could be found with a detector. ::g

https://www.antiquesilverspoons.co.uk/p ... spoon.html
[/quote]
Read my post, all "Modern" silver 8-|
[/quote]


In that case look at these designer rings:

https://www.google.com/search?q=britann ... 8&bih=1024

It ain't common but it's still out there! And if it's out there some poor sap will lose it. :D
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Re: Why does some silver not tarnish?

Post by hammy20 » Wed Jul 17, 2019 9:19 am

Recently pulled a silver ring of the beach,thought it was a washer! Turns out to 10gm of "Argentium" silver:
Argentium silver is a brand of modern tarnish-resistant silver alloys, containing either 93.5% or 96% silver. Argentium alloys replace some of the copper in the traditional sterling silver alloy (92.5% silver + 7.5% copper) with the metalloid germanium. Argentium's patents refer to percentages of Zinc and Boron present in Argentium silver. Both Argentium alloys exceed the standard required for hallmarking as sterling silver and Argentium silver 960 meets the standard for hallmarking as Britannia silver (95.84% silver).
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Re: Why does some silver not tarnish?

Post by Bootneck45RM » Wed Jul 17, 2019 4:11 pm

Hi Hammy20,
Heres one I recovered from 10 inches of damp sand/fine gravel at my local beach. It is fully hallmarked, with "TGF 925, plus lion etc etc" and apart from a soapy wash is as I found it. Apart from the band being slightly out of shape its eminently wearable.
Then - when you compare two George sixpences, one prior to 1920 and the other after, it does seem to indicate (generally) that the less pure the silver, the more likely to any corrosion.
I know this dosnt give any reason, but seems to give credence to the former posts.
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