White gold is an alloy containing gold -- which is yellow -- along with nickel, palladium and other whiter metals to make the alloy appear white. Since there is gold in the alloy it will always appear yellowish. The more gold in the alloy, the more yellowish it will appear.

The karat grade will always indicate the amount of gold in the alloy. For example, if you have a gold item that is 18K then there is 75% pure gold. So for 18K, this only leaves 25% of the alloy for other metals to make it whiter. This is why 18K white gold is more yellowish than 14K white gold.

White gold is almost always rhodium plated. Rhodium is a silver-white metallic element that is highly resistant to corrosion, and is extremely reflective. It is used as a finish for jewelry, mirrors, and search lights. It is also used in electric connections and is alloyed with platinum for aircraft turbine engines. Another use of rhodium is manufacturing of nitric acid and used in hydrogenation of organic compounds.

Rhodium usage is dominated by autocatalyst applications where it is used together with platinum and palladium to control exhaust emissions. It is a common practice in the jewelry trade to put a rhodium plate on white gold jewelry.

Platinum can also be rhodium plated but sometimes it is left in it's natural state. Rhodium is very white, reflective, extremely hard and virtually tarnish proof. Platinum on the other hand normally appears to be a more grayish white and not as bright. This is why it is sometimes plated, unless it has a good amount of palladium in the alloy.

When the plating on platinum begins to wear thin you don't notice it as much, but you do on white gold because the alloy is yellowish. This is why it's recommended that you purchase wedding bands. It's much more expensive in platinum, but it is worth it in the long run. The plating will probably wear off with 1-5 year's wear, depending on how rough you are on the rings, and how much rhodium plating is on the ring.

Gold jewelry requires maintenance to keep it looking brand new. To have a gold ring rhodium plated, it'll probably cost at least $20-30 for about 0.25-0.50 microns.

If it is a two-tone ring, it has to be applied by hand with a brush rather than immersing the whole ring in the electroplating tank. Two tone rings will cost more to maintain their appearance.

If you want to make a white gold wedding band very durable, you can get it plated with a layer of platinum or palladium of 1.0-1.5 micron thickness. That's followed by a good 2.5-3.0 micron thickness of rhodium plating. This will cost approximately $100.

Almost all white gold fashion jewelry from Italy is rhodium plated. For example, most ladies bracelets are rhodium plated. This is why they look so shiny and white.