Silver
Pure silver does not tarnish, but it is too soft on its own to be used in jewelry making. Sterling silver is 92.5% pure silver and 7.5% other metals (often copper) and the “other metals” are used to make sterling silver harder and therefore suitable for jewelry making. It is the ‘other metals’ that oxidize and cause the sterling silver to tarnish.
Rhodium
Rhodium is a member of the platinum group of metals, and as of May 2011, it costs more than 50 times more than silver! It is about seven times harder than silver, but it only reflects about 75% of incident light compared to 95% for silver, and therefore appears less shiny. Silver can be given a fine rhodium plating to add a degree of scratch and tarnish resistance to an item of jewelry, albeit at financial cost given the high price of rhodium and the labor involved in the plating process. .
Pros and cons
Initially, the rhodium plated piece may appear somewhat less shiny than the equivalent plain silver piece due to the less reflective nature of rhodium compared to silver. However, unless the plain silver piece is kept highly polished, the anti-tarnish properties of rhodium plating will make the plated piece appear shinier over time. Also, unless you were to place two similar pieces side by side for comparison purposes, one rhodium-plated and the other not, it’s doubtful you’d realize the plated piece wasn’t as shiny as it could be.
Sometimes it is the case that it would be difficult to clean silver even if you wanted to. The delicate filigree of silver can make cleaning impractical, and gemstones set within jewelry can be affected, even damaged, by certain cleaning agents. Rhodium plating the silver may be the best option in these circumstances.
Although rhodium is a hard metal, the thinness of the plating layer (about one four-hundred the thickness of a human hair) means that the degree of scratch and abrasion resistance it offers is limited (but useful nonetheless). . That thinness also means that even with normal use, the rhodium plating will eventually wear off over time, leaving unsightly blemishes on the jewelry’s surface. Jewelry can be re-plated, but this is often too expensive for anything other than a highly prized piece. Also, if a piece of rhodium-plated jewelry it does scratched or worn away, it is not as easy to repair as the entire piece may need to be replated after the repair is done.
Conclution
So is rhodium-plated silver jewelry a good idea or a bad idea? Well, as always, it all depends. If you really hate cleaning your jewelry, then rhodium plating may be just what you’re looking for. However, be prepared to throw the jewelry away once the plating begins to wear away, or bear the cost of re-plating it. If you don’t mind cleaning your jewelry, then you will have a brighter piece than could ever be achieved with rhodium plating, and over time, it will develop that beautiful patina that is unique to you. It seems there really is no such thing as a free lunch!