Another problem with nickel as a component of white gold alloys is a percentage of the population experiences a degree of allergic reaction to even trace amounts of it in a piece of jewellery. This is especially true for earrings or other jewellery that penetrate the body. The European Union (EU) has very strict limits for the amount of nickel that may be present in jewellery, determined by tests to measure how much of the metal leaches from an item. As such, white gold jewellery manufactured in the EU is predominately made from alloys containing palladium.Â
Although North America has not adopted standards for nickel content, palladium alloys are also increasingly used here. Their colour is generally greyer than ‘silvery’ white and some of them are rather soft, which limits their use for some purposes. That said, the relatively low price of palladium can make them attractive options. Some palladium alloys comprise metals that are added to increase hardness. Here, the colour tends to be greyish and the techniques for casting and annealing are specialized. However, palladium alloys can offer a good alternative for some applications.
A jewellery colleague of mine in the Unites States has a patent pending for alloys combining palladium or platinum with small amounts of rhodium. They offer a very attractive white colour that does not require electroplating and has zero nickel content. The alloys also have improved hardness and durability compared to traditional platinum and palladium blends. Specialized techniques are required for producing the alloys and for their subsequent casting and manufacturing, but their development presents an exciting new frontier.Â