Plating of Sterling Jewelry
Over the past few years, we have noticed
more and more products described as "rhodium plated
sterling silver." Here we explain what this new
trend is all about.
Rhodium is related to platinum. It
occurs naturally in ore deposits, but is quite difficult
to extract. For this reason, it was not even discovered
until 1803. Most rhodium is mined in South Africa,
but some rhodium is also produced in Russia and Canada.
This metal is silver-white in color,
resistant to tarnish and other forms of corrosion, even
acids, and very shiny. It is so reflective, in
fact, that it has been used in mirrors. It is used
in jewelry primarily as a hard protective plating for
sterling silver and white gold. It is applied as a
thin coat through a process of electroplating.
While rhodium is reflective, silver is
even shinier. As a result, sterling silver coated
with rhodium will not be as bright and shiny as the
underlying sterling piece would have been without
plating -- at least initially. However, over time silver
can tarnish and get tiny scratches. Rhodium
coating can minimize such problems. The effect is
that as time goes on, rhodium plated sterling will
continue to keep its fresh look longer. It should
be noted, however, the the plating can wear off
eventually and that replating may be necessary. If
an original coating of .25 microns has been applied,
replating may not be necessary for quite some time.
Rhodium plating is not suitable for all
sterling jewelry. Sterling Balinese jewelry, for
example, is typically antiqued; this is an important
feature of the style. Rhodium plating would
interfere with the antiquing process.
The price of rhodium, like other precious
metals, is quite volatile. Over the past year, its
prices has ranged from around $2000-$6800 per ounce.
That's a lot of variation!