Rhodium plating is a chrome-like finish normally applied to gold rings to create what is called "white gold," but is actually yellow gold that is plated. Gold is always a yellowish color and for those who prefer jewelry to be silver-colored, they can choose gold-plated with rhodium. You can easily tell if a ring is rhodium-plated by a few simple techniques.
Perform the light test. Under a bright light look at the underside of the ring where your finger comes in contact with table surfaces. If the ring is rhodium-plated, the yellow gold will show through slightly due to the everyday wear of the ring.
Check for rhodium plating on a new ring. If the ring has not been worn, your jeweler will tell you if the ring is plated or whether it's a more precious silver-colored material like platinum. If you do not have access to a jeweler, you can check the underside of the ring with a magnifying glass. There should be a stamp such as "14k" or "10k" to signify what type of gold the ring is made of. If you see this stamp, and the ring is silver-colored, it's rhodium-plated.
Check for rhodium plating using the the "wear test." If the ring maintains its chrome/silver finish for multiple years, without showing any wear back to a gold color, the ring may not be plated and is most likely platinum, which is a more valuable material than gold.
Have your ring re-plated on a regular basis to maintain its sparkle. Rhodium plating is not a permanent coating and will wear off over time. You will need to get your ring re-plated as often as every six months depending on the quality of the original plating job.
Do not wash the dishes or apply lotion when wearing your plated ring. This contact with other chemicals will cause the rhodium to wear off faster.