The Chemical Composition of White Gold

White gold is a popular alternative to yellow gold, silver, or platinum. Some people prefer the silver color of white gold to the yellow color of normal gold, yet may find silver to be too soft or too easily tarnished or the cost of platinum to be prohibitive. While white gold contains varying amounts of gold, which is always yellow, it also contains one or more white metals to lighten its color and add strength and durability. The most common white metals that form the white gold alloy are nickel, palladium, platinum, and manganese. Sometimes copper, zinc or silver are added. However, copper and silver form undesirable colored oxides in the air or on the skin, so other metals are preferable. The purity of white gold is expressed in karats, the same as with yellow gold. The gold content is typically stamped into the metal (e.g., 10K, 18K). The Color of White Gold The properties of white gold, including its color, depend on its composition. Although most people think white gold is a shiny white metal, that color is actually from the rhodium metal plating that is applied to all white gold jewelry. Without the rhodium coating, white gold might be gray, dull brown, or even pale pink. Another coating that may be applied is a platinum alloy. Typically platinum is alloyed with iridium, ruthenium, or cobalt to increase its hardness. Platinum is naturally white. However, its more expensive than gold, so it may be electroplated onto a white gold ring to improve its appearance without dramatically increasing the price. White gold that contains a high percentage of nickel tends to be closest to a true white color. It has a faint ivory tone but is much whiter than pure gold.  Nickel white gold often does not require plating with rhodium for color, although the coating may be applied to reduce the incidence of skin reactions. Palladium white gold is another strong alloy that may be used without a coating. Palladium white gold has a faint gray tinge. Other gold alloys result in additional colors of gold, including red or rose, blue, and green. Allergies to White Gold White gold jewelry typically is made from a gold-palladium-silver alloy or gold-nickel-copper-zinc alloy. However, about one in eight people experience a reaction to the nickel-containing alloy, usually in the form of a skin rash. Most European jewelry manufacturers and some American jewelry manufacturers avoid nickel white gold since alloys made without nickel are less allergenic. The nickel alloy is most often encountered in older white gold jewelry and in some rings and pins, where the nickel produces a white gold that is strong enough to stand up to the wear and tear these pieces of jewelry experience. Maintaining the Plating on White Gold White gold jewelry that has a platinum or rhodium plating typically cant be resized because doing so would damage the coating. The plating on jewelry will scratch and wear over time. A jeweler can re-plate the item by removing any stones, buffing the metal, plating it, and returning the stones to their settings. Rhodium plating typically needs to be replaced every couple of years. It only takes a couple of hours to perform the process, at a cost of around $50 to $150.