Greetings to you all,
For those of you who think that high carat golds don’t tarnish, THINK
AGAIN. They do. As head of Development group for Lazurde, the world’s
largest manufacturer of high carat gold jewelry (at 24 tons/ year), I
get to see On a weekly basis returned goods from the market from our
trade-in option in our showrooms that are severely tarnished
(basically the gold color changes to a deeper shade of orangy red, a
much nicer color than the original if you ask me). It mostly depends
on the alloy composition you are using. In our part of the world (Saudi
Arabia), 21K red gold is most prized, which usually has over 65% of
the alloy content in copper (the culprit), whereas you almost never
see such high copper content in the west unless it is accompanied by
the usual deoxidizing agents in the alloy such as silicone. The only
problem is that when adding silicone to your alloy, you start having
problems with grain size, as such you need to add grain refining
agents such as boron. However in this part of the world most people do
not buy ready made alloys which contain antioxidants. Instead they mix
their own alloys out of silver and copper alone. So my suggestion to
you is to contact your alloy supplier and enquire about high carat
alloy that contains antioxidants. My guess is that alloy will be much
harder than the one you are using now and thus will be much more
scratch resistant. You might want to contact an alloy manufacturer
that does business in the East since they have more experience with
these problems, such as Leg’Or or Pandora of Italy. If you need their
addresses, e-mail me and I will send them to you. As far as coatings
are concerned, it is the opposite that you should seek. My experience
has been that jewelry items that are cleaned in a dish washing liquid
containig ultrasonic machine end up oxidizing even more due to the
chemical residue left on the piece. As such try to use the recommended
solution by the manufacturer and don’t skimp on this. It’ll end up
costing you more in the long run. But an extra weight in the form of
coating will not do the trick because it will most certainly wear off,
and in some instances might give you some problems with the
authorities (depending on your local laws) Good luck.