What is Rhodium?
inJanuary 4, 2008 - 10:25am
Overheard recently at an antique market:
These shoppers raised an interesting point about a common misnomer that has come into vogue among sellers of vintage costume jewelry. At shows and on-line, it is easy to find collectible jewelry sold as "set in rhodium" or a rhinestone brooch with "rhodium mounting". So what is rhodium? Should you expect to buy a piece of solid rhodium jewelry for $50?
Rhodium (number 45 on the Periodic Table for the truly curious) is a silvery-white hard metal that is often found in platinum ores. It is the most expensive precious metal. Aha! There's a clue for the beginning jewelry collector. Why would the most expensive precious metal be used to make mountings for rhinestones? Simply put, it wouldn't.
So why do sellers refer to their costume jewelry as rhodium? Is there any of this precious stuff in their jewelry pieces at all? To unravel the mystery, let's take a look at:
The Properties and Uses of the Element Rhodium
In its natural solid state, Rhodium is far too hard to work, but is used as an alloy in the smelting of platinum and palladium for use in fine jewelry because it adds hardness and durability to the platinum. Okay, but that seller at the market was selling a costume brooch, so why did she refer to it as rhodium? That's easy. Like many sellers, she has confused rhodium with rhodium plating. And just as it is not correct to call an item plated in 14K gold simply "gold", it is not correct to call an item plated in rhodium simply "rhodium".
What is rhodium plating and how long has it been used?
Well, in the 1930's rhodium electroplating began to be used by some silver flatware makers to produce sterling flatware that would not require frequent polishing. The use of rhodium plating spread to white gold and sterling silver jewelry as a means of creating a highly durable, tarnish resistant surface. Some jewelers refer to the resulting finish as "bright white".
The use of rhodium plating on base metal, "pot metal" and stainless steel jewelry findings and settings did not come into wide use until after World War II. And over the last 40 years, advances in technology have allowed even thinner layers of rhodium to be bonded with the surface of metals.
In short, while no costume jewelry, new or vintage, is "set in rhodium", much of it is rhodium plated. Keep this is mind when shopping for your collection. And if you are selling vintage jewelry, remember to show your professionalism and knowledge by properly identifying those shiny jewelry pieces as rhodium plated.
For more information on the proper way to sell precious metals and jewelry, you may wish to review the FTC's Guides for the Jewelry, Precious Metals, and Pewter Industries by clicking here. In part, the Guidelines read, "It is unfair or deceptive to use the word... "rhodium" ... or any abbreviation to mark or describe all or part of an industry product if such marking or description misrepresents the product's true composition."
Although you may not consider yourself a member of the Jewelry Industry, if you are selling jewelry on-line or in any other venue, you are indeed bound by the FTC guidelines.