[Jewelry making - Article 00725] - Re: [Orchid] Does sterling silver ever rust?

[Peter W . Rowe]

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>        Wow, talk about confusing!  OK, next time I go to a show, how
>     will I know if what I'm buying is sterling?  And, if .925 is mainly
>     silver and part copper, what percentage is then allocated to the
>     nickel and rhodium plating? 

    Sterling silver is 92.5 percent silver, and 7.5 percent copper.  The
    electroplated finishes that may be applied over the sterling silver
    are not generally considered as part of the main metal content.  An
    error, technically, but since the plated layers are usually extremely
    thin, their actual effect on the overall "by weight" composition of
    the object is usually very little, probably not enough to affect the
    legal definition of sterling silver..  But I suppose you are correct
    in wondering if it makes the marking for sterling silver inaccurate,
    and it might indeed do so on things made of very thin metal 

    Personally, I prefer to buy only sterling silver that is not plated
    at all. I don't especially like the color of rhodium plating on
    sterling.  It's an improvement when done to white gold, which often
    is not all that white, but on sterling, though it does prevent
    tarnish, the purpose of the plating, it totally masks the wonderfully
    white color of the silver.  Useful on things like those styles of
    chains or objects where one cannot clean off tarnish, and an
    oxidized finish on recessed areas isn't desired.  But I'd much rather
    avoid it when I can. 

    By the way, I'd note that while I mentioned that the nickel
    underplate layer on a rhodium plated item might show some magnetism,
    I doubt that it would ever be that strong an attraction, due to the
    very thin nature of that layer.  And nickel is not that strongly
    magnetic in any case.  Also, in checking a few items I've got, only
    some showed detectable magnetic attraction, using a rather strong
    magnet.  If the nickel barrier layer is very thin, perhaps you don't
    notice magnetic effects at all, especially if you're not using a
    powerful magnet.  Of the things I checked in my scrap pile and
    assorted sterling chains, most of the stuff I think is rhodium plated
    showed at least faint attraction to my magnet, with is one of those
    rare earth very powerful ones.  Two items were strongly attracted to
    the magnet, and in checking, I noted that both those scrap chains
    were not marked, made of links that were just crimped shut, not
    soldered, and upon further testing, turned out to be actually made of
    silver plated steel wire.  There were things I found at garage sale
    lots, or the like,  so who knows where they were purchased  or
    whether their owners thought them to be silver. Nevertheless, the
    rhodium colored surface was otherwise indistinguishable from the other
    rhodium finished stuff, an indication that suggests some care may be
    needed in buying things from uncertain sources. 

Peter

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