At the risk of slight oversimplification, if the "other metals" in the alloy are copper or silver, the gold remains yellow; whereas if the "other metals" are palladium and/or nickel, they have a "bleaching effect" and the mixture becomes whitish, i.e., "white gold".
Nickel is much cheaper than palladium (which is a precious metal), so nickel is widely used in white gold jewelry in the U.S. But so many people are allergic to nickel that it is forbidden in jewelry in Europe, and palladium would be used there instead.
A. Rhodium is a very precious metal that can cost ten times as much as gold or more! Although Rhodium is generally not considered a feasible material to make jewelry from, because it is stressed & brittle, and very difficult to "work" properly for jewelry making, and its price is terribly volatile, Rhodium is fabulous as a plating for jewelry because it is glitteringly, dazzlingly, white and mirror-like. It's like chrome, but much whiter, and one of the most reflective of metals.
Rhodium plating makes diamonds look bigger and better because it's so bright that it glints like the diamonds. From a couple of feet away and under most lighting conditions it's hard to see where the stones end and the metal begins. Nothing sets off diamonds like rhodium plating does. So most white gold jewelry today is rhodium plated. But the rhodium is only a plating and therefore it will wear off eventually and require replating.
A. Yes, things have changed a lot! Years ago, white gold rings were not rhodium plated, and today they usually are. So which is better and why?
Well, if you feel that heirlooms should be a once in a lifetime purchase that lasts forever without any further attention, you may not be happy with a rhodium plated ring, because rings are "high wear" items, and no matter how high the quality of the very thin plating, it will wear off over time and require replating.
But if you love today's brilliant, dazzling, ultra-white diamond-like look, recognize that you simply can't get it from an unplated ring ... and you never could. No matter how well white gold is made, it's a metal which is about half yellow gold and it will never even come close to offering the flashy glint of rhodium plating. Yes, your grandmother's ring lasted decades and never needed replating, but it was never dazzling like today's rings -- it was white enough for people's taste in a different time, but for many people it is not scintillating enough for their taste in this age of "bling".
A. You may be reading this because you are unhappy that your ring is getting "yellowish" and you want to know what is happening and why.
If today's rings were just like your grandmother's ring except with a layer of rhodium plated onto them, everyone would probably be happy. If you wanted your ring to knock your eye out you'd get it replated when needed; and if a more antique look pleased you, or you object to replating heirlooms, you'd just ask the jeweler not to plate it.
But, unfortunately, most of today's rings are not of the same alloy as your grandmother's! Once the jewelry companies recognized that "it's going to be rhodium plated anyway" they talked themselves into believing that the underlying metal didn't really need to be the pleasing white shade of your grandmother's ring. They were wrong, weren't they?
|White gold is graded by color, i.e., whether it's white enough to be left unplated -- and most of today's "white gold" is not white enough. But there are some white golds like Stuller X1 14K and W.R. Cobb's "Precise® White Gold" which are reputed to be at least as white as your grandmother's white gold.|
(If you are interested in the details, see the article "White Gold Alloys: Colour Measurement and Grading" at http://www.docstoc.com/docs/111740769/White-Gold-Alloys-Colour-Measurement-and-Grading-Dippal, which explains this whiteness factor).
What is happening to you is that the rhodium plating is wearing thin, and you are seeing the "yellowish" color of your "not white enough to go unplated" gold starting to show through. In fact, jewelry stores in the center aisle of shopping malls at Christmas sometimes save on inventory costs and delivery time by rhodium plating yellow gold jewelry -- and the contrast as they start to wear is terrible! You might get away with rhodium plating a yellow gold pin or brooch, because these are seldom touched and suffer very little wear, but rhodium plating a yellow gold ring that is worn regularly will probably prove very unsatisfactory.
A. This is the big question, but the answer isn't easy. First, it depends on whether the item is a ring (rings suffer a great deal of wear), or a pin or brooch which receives almost no contact. And it depends on whether you wear the ring constantly. To a minor extent it may depend on that old bugaboo "body chemistry". But the life of the plating also depends on two other very important and controllable factors --
Yes, you can get your yellow gold jewelry rhodium plated if you wish, but if the piece experiences significant wear, the good appearance may last only a fairly short time even if the rhodium plating quality is good, and almost no time if the plating is poor.
Conclusion: If possible, try to make sure that the white gold jewelry you are buying is a good shade of white before plating so that there will be little contrast as the rhodium plating gets thin. And if your jewelry store can't rhodium plate the jewelry well enough for an acceptable life, try to find another jeweler or a specialty plating shop who can.
Good luck with your ring, and if you found this page informative, please tell others about it. If you would like to hear some other opinions on white gold and rhodium plating, and hear other people's tales of satisfaction or dissatisfaction, this site has dozens of public forum threads on this topic, including this sampling:
- White gold discoloration
- Can an 18K white gold necklace be turned back to yellow gold?|
- Palladium-alloy white gold versus nickel-alloy white
- How do we go from Yellow to White Gold
- White gold ring causes rash
- Sizing rhodium plated white gold rings
- White gold or Rhodium plated confusion or deception
Disclaimer: It is not possible to diagnose a finishing problem or the potential hazards of an operation via these pages. All information
presented here is solely for general reference and does not represent a professional opinion nor the policy of an author's employer. The
internet is largely anonymous; some names may be fictitious and some recommendations may even be deliberately harmful.
If you are seeking a product or service related to metal finishing, please check these Directories:
Jobshops Capital Equip. & Install'n Chemicals & Consumables Consult'g, Train'g, Software Environmental Compliance Testing Svcs. & Devices Used & Surplus