White gold is a blend of several metals including yellow gold, silver, and palladium. Just as many sterling silver rings are plated with rhodium, so are many white gold rings. In both cases the purpose is to enhance the appearance.

When you purchase an inexpensive sterling silver ring I do not believe that it is a surprise that it will not last a life time. On the other hand when you pay thousands of dollars for an engagement ring, I do think that you should know whether or not a coating of any type has been used to enhance the finish. The most common enhancement for white gold is rhodium plating. Since an engagement ring is normally worn ever day within one or two years of purchase the ring might start to look towards the gray side. That appearance is the natural color of white gold. The white gold can be cleaned, polished and then replated.

A new white gold ring is very attractive. When plated with rhodium it will have an almost identical appearance to platinum. White gold is much less expensive than platinum. Most white gold jewelry is 14Kt. That means that there are 14 units of yellow gold mixed with 10 units of a blend of silver, palladium and other trace metals. When gold or silver is mined there are trace amounts of related metals in the ore. Therefore the origin of the ore and how well it has been refined will result in slightly different alloys. Silver is the least expensive metal, if nickel is not used, to blend with yellow gold and therefore jewelry manufactures tend to use blends that are high in silver. Adding more of the expensive palladium will produce a whiter more brilliant finish. Under United States law the gold content must be stamped on a piece of jewelry. However I am not aware of a requirement to disclose the actual composition of the alloy. A jeweler should be able to tell you if a white gold ring is plated, or if it's white brilliance is the result of the use of a better alloy.

In the past it was common practice to use nickel to create a white gold alloy. Many people experienced a skin rash caused by the nickel as it aged and formed oxides. Today that practice has been somewhat discontinued. In Europe the EU has banned the use of nickel in jewelry. If you have older white gold jewelry and do experience a skin rash you might consider having the piece refinished with a rhodium plating. Since the plating will come in contact with your skin, and shield it from the nickel, the rash should not reoccur until the plating has worn off.

On some of the television shopping channels they are currently selling costume jewelry with descriptions that give the impression that the jewelry is made with precious metals. If you pay close attention, they do disclose if real gold or sterling silver is being offered. There is nothing wrong with purchasing costume jewelry. Just be sure that you are purchasing real gold or sterling silver, if that is what you expect to buy.