Ways of Testing Silver Content?

Questions on polishing, restoration, conservation + manufacturing techniques

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blackice1981
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Ways of Testing Silver Content?

Postby blackice1981 » Thu Feb 21, 2008 6:55 am

Hi!

Was wondering what methods I can use to test silver content on silver flatware. Sometimes I get the odd piece that is hard to tell if it's silver or not when the hallmarks are questionable (having a test that can id silver vs plate would be good). If there is a method of determining silver content (ie .800 vs .925) that would be even better.

I've seen a "Pen" like device being sold on eBay. Has anyone tried one of those?

Also seen "acid" drop tests, but worry that might damage a piece.

Any suggestions?

Thanks!
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rheta
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Postby rheta » Thu Feb 21, 2008 9:19 am

I use the acid test. The acid is designed to eat away at everything that is not sterling silver, therefore causing a bubbling or discoloration that tells you it isn't the real deal. The acid doesn't damage the piece visibly and it's always best to do it in an inconspicuous spot. They key is you have to dig down beneath the surface metal to get a truly accurate test, a bit of rough sandpaper or file does the trick. Again, it needs to be done in an inconspicuous spot and a very small spot. The sanding or filing spot can be buffed back to its original state if it's solid silver.
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salmoned
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Postby salmoned » Thu Feb 21, 2008 2:28 pm

Density.
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byron mac donald
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Postby byron mac donald » Fri Feb 22, 2008 3:33 am

Hi Blackice-

Wow... have you opened up a can of worms here! Hopefully someone will post a thread to some past ideas on how to test for purity, I can not find the discussion from a couple of months ago. The best answer that would identify the true content; was to have it assayed, the problem is that it would have to be destroyed to do so.
The second best method seems to have been, as Salmoned has stated a density test. The problem here is that you need very... very... sensitive scales (expensive and complicated).
The third option was as rheta has mentioned, an acid test; here the problem is that you have to mar the piece in an area to perform it.
Hopefully, the admin or others will be able to find the long discussion I am reffering to, regretably I did not save it.
As far as the hallmarks being questionable, I do not see why they should be considered so. If it says sterling, than it is most likely sterling.

Regards- Byron
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Postby dragonflywink » Fri Feb 22, 2008 1:53 pm

Bit bothered by this post, as a collector of both silver and some silverplate (the design is the important thing for me), wish I could take all the acid testing kits, sandpaper(!), files, buffing wheels, etc. out of the majority of hands, some of the damage is quite disfiguring (and I'm not all that picky). Most silver can be IDed by the marks if proper research is done, and unless you're planning to scrap it, the intrinsic value of the various silver contents (800 as opposed to 925...) really isn't all that important. My acid testing kit hasn't been touched in at least 15 years, and was really only for use with a touchstone when I was dealing in unmarked antique gold jewelry, and then, frankly, a jeweler friend told me to put it away and let someone who knew what they were doing test for me. If you're talking small pieces, my jeweler has determined metal content for me with his specific gravity scale, coin dealers also usually use this method.

~Cheryl
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salmoned
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Postby salmoned » Fri Feb 22, 2008 3:03 pm

I do specific gravity tests in a matter of 5 minutes or so with a used Ohaus Cent-o-Gram scale purchased on eBay for less than $40. It can measure up to 10 troy ounces to .01 grams. I weigh the object (a). I suspend the object with fishing line and reweigh (b). I immerse the suspended object in water and weigh it once again (c). Density (in g/cc)=a/(b-c). This value is added to my record of the object for future reference. By measuring numerous objects of known composition, I establish density ranges for different compositions.
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blackice1981
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Postby blackice1981 » Mon Feb 25, 2008 6:31 am

Hello Everyone, Thank you for all the posts.

"salmoned", I am going to give the Specific Gravity test a try, since I don't wish to damage the items I'm testing. The test seems easy enough to do, although I'm going to need to pick myself up a new scale.

I have a specific question regarding your Ohaus scale. The cup/beaker of water has a weight which would max out the scale (as it would weigh more than 10oz). I assume you can just manually dial the scale into zero (with the cup/beaker on it) before you suspend the item in it, correct?

Seems like a silly question in a way, but having never used this type of scale I figure it's best to be sure before buying a scale. I already have a scale (digital) that can measure up to 100g to .01 g, but am sure it couldn't zero out the weight of a cup unfortunately.

Thanks again everyone for the posts, I appreciate the info!

Best Regards!
Paul
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salmoned
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Postby salmoned » Mon Feb 25, 2008 2:53 pm

You don't weigh the water! You only weigh the object [suspended in the water]. It will lose a portion of it's weight, so if you can weigh the object itself, you can perform this test.

Also, there is no need to reset the scale's zero - it's just added effort to no effect. When I suspend the object, the small weight of the fishing line adds to the total weight, but then subtracts out when I subtract the weight of the object suspended in water. In determining the volume, it's only the weight difference that matters.
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blackice1981
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Postby blackice1981 » Mon Feb 25, 2008 7:06 pm

Good Afternoon,

Thanks for reply.

I'm going to pick myself up a new scale & give this a try.

Best Regards,
Paul
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salmoned
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Postby salmoned » Mon Feb 25, 2008 8:33 pm

You may be able to use your current scale by rigging a contraption that will suspend the object from your scale's weighing surface. As long as the weight of the device (such as a coat hanger wire bent into a 'C' shape) and the object doesn't exceed your 100 gram maximum.
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kaystiles
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Re: Ways of Testing Silver Content?

Postby kaystiles » Wed Oct 17, 2012 12:52 pm

Try foundation, yes, make up "foundation" rub a tiny amount on back of hand then take metal you are testing across your hand across the make up and if it leaves a dark mark 99.9 times out of a hundred
the dark mark means real gold and real silver. Now other metals leave marks they are light, alot lighter.


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