Back to Ganoksin | FAQ | Contact

Copper & Silver [was: Gold teeth]


#1

How can I test the ?silver?

G’day; The standard test for silver is firstly, get it into
solution by dissolving a very small amount in nitric acid. (It
might also be possible get a little into solution by boiling with
ferric nitrate if you don’t fancy nitric acid) To a portion of
the solution, add common table salt and the presence of silver is
indicated by the appearance of a milky precipitate which
coagulates on shaking and turns a violet colour on exposure to
strong light. A confirmation is obtained by adding plenty of
ammonia (slowly!) when the precipitate dissolves to give a clear
solution.

To another portion of the solution add ammonia (slowly!) and
after the acid is completely neutralized a blue colour will
appear, indicating the presence of copper. This test can
determine whether the original metal was fine silver or a copper
alloy like sterling.

Oh, and as the ‘hardened toothpaste-like material looking like
silver’ was mentioned, be very careful with this as it might be
an amalgam of silver and mercury. If you really want, you could
test for the presence of mercury using the same solution as
above, because the white precipitate won’t dissolve in ammonia
and won’t change colour with light. As silver is fairly cheap,
you may not want to mess about with that particular material.
Cheers,

    /\      John Burgess
   / /
  / /      Johnb@ts.co.nz    
 / /__|\
(_______)  "New and Improved" appears in advertisements a

lot now. My experience of that is; ‘Half the value and twice the price’