[Jewelry making - Article 01038] - Re: [Orchid] Test For Sterling Silver

[John Burgess]

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>         A lady came into my store the other day with an old teapot
>     that belonged to her grandmother.  I don't deal in antique silver,
>     but I wanted to at least tell her if it was solid sterling silver
>     or not. It "looked" like silver.  There was a manufacturer's name
>     on the bottom but nothing like "925" or "sterling". 

    G'day;   Firstly I would suggest that if it isn't stamped with the
    usual marks is is most likely plated.  The pot could be
    electroplated, or if it is really an antique it could be what used to
    be called 'Sheffield plate'  This was made by rolling silver or
    sterling onto a piece of base metal such as one of the brasses to
    make a thin laminate, and is worth more than modern plate; rarity
    value. Another base metal was EPNS;  electroplated nickel silver.
    (nickel silver contains no silver!) 

    A simple test for silver is to dissolve a tiny bit in a drop of warm
    nitric acid. Add common salt solution to the result and if silver is
    present you will get a white precipitate of silver chloride which
    coagulates upon shaking and turns purple-ish in direct sunlight.   If
    you add ammonia dropwise to this the precipitate will re-dissolve,
    then if you continue to add ammonia a pale blue colour will indicate
    the presence of copper.  So the metal could be sterling silver, or it
    could be a brass, silver plated.   Without very specialised equipment
    it is difficult to give a scientifically based opinion on which it
    is. 

Cheers for now,
John Burgess;   johnb AT ts.co.nz of Mapua Nelson NZ

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