Purple Silver?

Hi there everyone, I have mainly lurked in the past but my
imagination was sparked today with a metallurgy lecture. With
discussion about how to make green, blue, and purple gold, I got to
thinking that I would be interested in experimenting with the idea
of colored alloys of silver (gold is a little out of my price range
for experimentation). So I guess I’d be interested to know if there
are any others that have had this crazy idea before and what has been
done about it. After my finals I’ll give fine silver and iron or
aluminum a try to see what will happen, any other ideas?

Jocelyn, Interesting question and drives me to ask “Why?” Not
because it’s not an intriguing idea, but to help me think through the
pros/cons of the approach.

I use intense purples and peacock greens a fair amount in my work in
silver. I love the iridescence that comes from a well-crafted
patina on silver, and as far as I know you can’t achieve that effect
on gold. (I may be wrong as I don’t work in it all that much –
feel free to enlighten me on gold patinas!)

So far, I’ve achieved effects that are quite permanent (I use
lacquer or wax to “fix” the surface), with good control of where to
patina by using masks.

I assume with a truly purple-colored alloy, the coloration might be
more consistent, but would it be as rich? What about control and
heat-tolerance? Brittleness – like the problems with purple gold
that make it virtually unusable – would be a serious problem.

So what would the tradeoffs be in these two approaches? You’ve got
my mind working on it!

Karen Goeller
@Karen_Goeller
Hand-crafted artisan jewelry
http://www.nolimitations.com

I don’t believe that you want to try making the purple silver using
aluminum. It is my understanding that this is a hard and brittle
alloy that is not workable as a metal. There should be in
the archives.

Marilyn Smith

Thanks for replying. I guess I’d just be interested in an
experiment. I’ve used patinas to achieve purples and blues and lots
of other colors in the past but I am interested to see how others
would react to the colored silver alloy. My understanding is that
some alloys of aluminum and silver can be quite workable, but I am
yet to find out. Maybe a new trend has been started with the black
gold (and other colored alloys) around the marketplace. It would be
interesting to be one of the people that get a chance to use a new
(or old) colored alloy. The chemist in me wants to give it a try no
matter what the outcome, I will post the results on the list when I
have the time to give it a try, might not be before January, I’ve
acquired four new commissions in the past week:-)

The chemist in me wants to give it a try no matter what the
outcome, I will post the results on the list when I have the time
to give it a try 

Good luck in your endeavor. I’d like to point out that one of the
problems with creating new silver alloys is the fact that there is
traditionally very little alloy used in silver. I don’t know what
the FTC has to say about how much silver must be present to be
called silver, coin silver is 90% silver, but sterling and most
other silver alloys use only 2.5% other alloy. 18 karat gold on the
other hand consists of 25% alloy. That’s a huge difference. I’m
doubtful, but very interested, if one could substantially or
dramatically change the color of silver if one is limited to 2.5% of
the total weight in alloy. Perhaps it doesn’t matter, but I would
think that one of the benefits of using silver is that you can call
it silver. If you begin to alloy it so much that you aren’t able to
call it silver, why not use other metals; and if all you achieve is
the ability to patina the metal (the way you do black gold) and the
patina will wear off anyway, what benefit have you given yourself?
In fact, the one person who I know of who in the US has popularized
colored gold alloys, Steven Kretchmer, achieves success as much
because of the surface embellishment as he does for the color of the
alloy. Once the surface embellishment is worn off, there isn’t much
to the colored alloy; that goes for the “new” black alloy as well.
I’m not a chemist or metallurgist so I may be speaking out of line
here, but it seems to me that one of the advantages of gold is that
it is very non-reactive. Silver on the other hand is quite
sensitive to even atmospheric amounts of sulpher. This seems to me
to be a huge hurdle to cross. The tendency of silver to go black is
very strong, this is what makes it so great as an ingredient in
niello. In fact, as a matter of research, you should start looking
at the different colors that have already been achieved with
different niello formulas. You’ll find that many of them are quite
difficult to make and use, and of course you can’t call them silver
because it is only one constituent of the alloy. It would be the
place to start I would think.

Larry

loosely from Brepohl’s " The theory and practice of
Goldsmithing":

Up to about 5 % aluminum is soluble in the solid alloy. The
color is even whiter than usual and the rate of oxidation is
increased. These alloys result in embrittlement. During melting
and annealing Aluminum oxide can be easily formed in the grain
boundaries and cause the metal to break into pieces.

From somewhere else-- where I don’t remember – traces of aluminum
acting as a deoxidant may help produce a non tarnishing sterling.

Other technical references I have do not mention silver- aluminum
alloys. jesse