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 Post subject: Re: How to test for sterling
PostPosted: Sun Jul 26, 2015 3:38 pm 
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The Disney version is close to the truth, the story that is authoritatively recorded is that he told his slave to fill his bath. The slave, cracking daft (as we say here) fills the bath to the brim and walks off. Archimedes, rather than search him out to take some of the water out, gets in anyway and the surplus water starts to splash over the sides. At this point he realizes that the water displaced is equal to the volume of his body and thus he has a method of measuring the volume of an irregular solid and also that the water exerts an upward thrust equal to the weight of water displaced. Hence legging it through the streets of Syracuse to the Royal Palace shouting "Eureka" (I have found it). Quick witted does not begin to describe it!


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 Post subject: Re: How to test for sterling
PostPosted: Sun Jul 26, 2015 5:21 pm 
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Alan F. wrote:
A drip of the acid dichromate solution is quicker and more certain, only silver gives the orange colouration.

The orange color only proves that there is some silver in the alloy. It does not determine the material is sterling.


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 Post subject: Re: How to test for sterling
PostPosted: Sun Jul 26, 2015 6:12 pm 
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The shade of orange is a pretty good indicator, base metals in the alloy darken the orange colour and provide the varying shades. It is a lot more reliable in detecting fakes than checking S.G. as any competent metallurgist could mix up an alloy that looked silver(ish) and had the S.G. of sterling silver.


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 Post subject: Re: How to test for sterling
PostPosted: Mon Jul 27, 2015 3:24 pm 
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Alan F. wrote:
The shade of orange is a pretty good indicator, base metals in the alloy darken the orange colour and provide the varying shades. It is a lot more reliable in detecting fakes than checking S.G. …

What kind of a gemologist are you? :D :D You must be kidding :D :D Now, you are advocating a destructive test on the surface is better than a harmless test on the bulk of the material. :D
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… as any competent metallurgist could mix up an alloy that looked silver(ish) and had the S.G. of sterling silver.

What inexpensive metal would one use to raise the S.G. to 10.3, other than lead? However, that would lower the melting point and one could not use silver solder.


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 Post subject: Re: How to test for sterling
PostPosted: Tue Jul 28, 2015 7:20 am 
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What sort of a gemmologist am I? A highly suspicious one! I am not a metallurgist, but tungsten springs to mind as a reasonably priced heavy metal. On the other hand, what is wrong with lead? The fact that it cannot be silver soldered is surely immaterial, silver plated lead solder will do to deceive.
To my mind the deciding factor is convenience, setting up the specific gravity balance on the dealers counter is likely to be tedious but a quick whizz of the file and a dab of acid/dichromate solution takes seconds. Of course, the dealer may refuse to allow a test, in which case walk away. If he is not prepared to back up his claims for his merchandise it is almost certainly fraudulent. I always say to the dealer that if the silver comes up to scratch I buy and polish out the test mark myself, if it doesn't come up to scratch he will want to get it out of sight before it is seen by Trading Standards, for that would let him in for confiscation and a hefty fine. I don't often get an argument.


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