White Gold or Yellow Gold?
Gold is the oldest and one of the most precious metals. It is considered a precious metal since antiquity. This metal was discovered some 5,500 years ago, making it possibly the oldest precious metal there is.
The standard color of white in gold is not specified. Commercial white gold are not really white color but usually yellow-brownish and are plated with rhodium to increase luster.
Rhodium belongs to the platinum family. It is high in reflectivity. A very thin coat of rhodium is applied to most of white gold jewelries to make it appear shinier.
Rhodium is allowed in a number of countries even with those with regulations in Hallmarking. If rhodium coating is not subjected to undue abrasion, it will normally lasts up to 3 years before it fades to reveal the white gold color.
Nickel White Gold Restrictions
Nickel white gold is less popular than palladium white gold because around 12-15% of the female population is allergic to nickel. Nickel allergies often manifest as red skin rashes or irritation. This usually occurs when using nickel white gold in jewelries, zippers, fasteners and body piercing.
The European Union countries passed the EU Nickel Directive that limits nickel in jewelry and other items that comes in contact with the human skin. In Europe, nickel white golds are slowly being phased out and being replaced by palladium white golds. There are some jewelry though that contain low nickel alloys to conform to the standards specified in the Directives which are being sold there. Jewelry with low nickel content though is not an assurance that the wearer will not have allergic reactions to it.
Japan and china have similar regulations regarding nickel white gold. The USA has more lenient laws on nickel content. All US requires is that the jewelry be labeled as containing nickel. A number of other countries do not have regulations against nickel content and white golds are still widely distributed. In the EU, jewelry is labeled with 'non-allergenic' or 'nickel-free'.
Palladium white gold is more expensive that nickel. Since the regulation of nickel content was imposed, alternatives that are nickel-free and cheaper are being sought after. A number of new patented alloys have emerged in the market. These new alloys make use of manganese instead of nickel as gold bleacher. Some do not have palladium content while others have low palladium in them.
These new white gold alloys seemed to be harder and more difficult to make. The results are not pure white and require rhodium plating. Cracking and tarnishing problems are observed too. The compositions of these new alloys are not indicated in the label.
