I'd like to pass on as much info as possible on the new Argentium
stock many suppliers are now carrying. But first I would like to say
that it is a relatively new material and experience tells me there
will no doubt be growth and a bit of a learning curve. That's what
makes this Orchid group so great, we're all growing and sharing our
experiences. I'm not going to pretend I know everything about this
material, far from it really, but it is our responsibility as a
supplier to provide as much technical as possible.
Everyone in North America is obtaining Argentium from the same mill.
That mill has traditionally been set up to make traditional
sterling. Great pains are taken to eliminate oxygen from the
environment when producing traditional sterling silver. (Avoiding
oxygen is paramount to avoid fire stain issues.) Since the
Argentium is produced on the same equipment as the traditional
sterling is, the Argentium comes from the mill oxygen-starved.
Rio Grande will be happy to inquire with our mill about the
possibility of the Argentium being prepared in an oxygen-rich
environment, so that the germanium is "activated". However, in most
cases after purchase the silver will be formed, soldered, sanded and
polished, thus rendering the mill's "germanium activation" useless.
For now, when the final finish is obtained metal smiths should heat
any Argentium to achieve the full benefits of this new alloy.
I would like to make an observation. Someone, and I apologize in
advance I can't remember who, mentioned that Argentium was turning a
customers skin green. The first thing that came to mind was this is
a body chemistry thing, perhaps were going to see certain people
who's skin or body chemistry doesn't agree with the germanium oxide
Recently I posed a question to the Argentium technical folks and I
found their response quite helpful. My query was on Cynthia's paper,
in it there are two statements that read:
"Since the final polishing of a piece made of Argentium[r]
Sterling removes much of the tarnish-resistant germanium oxide
layer, one may wish to heat the Argentium[r] Sterling to speed
up the re-building of a protective germanium oxide layer. 250F
for 10 minutes is generally adequate." And then: "The surface
of Argentium" Sterling Silver has germanium which is oxidized
to germanium oxide. The reason this occurs is because germanium
is an 'oxygen getter'. It has a high affinity for oxygen even
at room temperature."
So my question was, if the germanium in sterling silver absorbs
oxygen at room temperature then is the step of creating an oxide
layer at 250F for 10 minutes really necessary?
The Argentium technical response was:
"I have carryed out accelerated tarnishing trials on samples
of polished and degreased Argentium Sterling that have been
heat treated/not heat treated and the heat treated samples do
give increased tarnish resistance! This indicates that the
germanium oxide layer has somehow been enhanced by the heat.
'The germanium at the surface will slowly oxidise to germanium
oxide in air. Of the three elements on the surface of the
Argentium Sterling silver (silver, copper and germanium) the
Gibbs Free energy values show that the preferred order of
oxidation is germanium then copper then silver.
'The way Argentium sterling silver works is to preferentially
oxidise the germanium so that the germanium oxide acts as a
barrier to the tarnishing reactions of the copper and the
silver (i.e. copper sulphide and silver sulphide formation).
'The benefit of heating the Argentium sterling silver to
promote this reaction is to do with which the rate at which
the reaction occurs. The Arhenius equation shows that the rate
of reaction is exponentially proportionate to temperature,
therefore a relatively small rise in temperature will result
in a much increased rate of oxidation of the germanium and
hence improved tarnish resistance of the Argentium Sterling
In a nut shell, if you want your germanium to be tarnish resistant,
heat treat it when all polishing/sanding is finished.
I would like to thank Trevor and Cynthia for being so generous and
sharing all their experiences and I apologize for leaving anyone
out. I encourage you all to read Trevor's blog and Cynthia's paper,
very informative and helpful. Thanks to both of you, you are both
truly an invaluable resource!
I'm sure there is much more to learn.
Rio Grande Technical Support
800-545-6566 ex 13903