Will not my wedding or engagement ring of white gold turn yellow stained?
There are frequent questions conserning the matter of fading the tinge of colour of white gold jewels. Thus I would like to focus on this point.
The simple answer to the above question is that any jewels made of white gold can turn yellowish when worn. But this can be avoided. How is this possible? It's because there are more types of white gold alloy used in jewellery production. It consequently depends on what type of white gold was the jewel made of.
In nature, only yellow gold can be found as a raw material.
White gold is made by alloying pure yellow gold with basic metals of white colours that 'beat' the original yellow colour in the gold alloy. White gold is added with zinc, nickel and palladium. And the ratio of these metals present in the alloy produces the intensity of its white colour, but also influences many other characteristics important in the production such as its hardness and castability.
White gold can be divided into three types:
White gold with palladium - these gold alloys are brightly white and soft which is advantageous for embedding stones in a jewel. They are therefore used mostly for the parts of jewels embedded with stones. Palladium alloys, for their little hardness, are not ideal for jewellery exposed to a load of constant wearing such as wedding rings or engagement rings. In addition, palladium is very expensive.
White gold with zinc - zinc alloys are harder than alloys of palladium but not too hard, so they are easily processable and most of them are well castable. They are therefore mainly used by big manufacturers producing jewellery by a method of casting into lost wax. And it is nowadays the vast majority of mass-produced, mostly imported products. This kind of white gold has a touch of yellow colour with an intensity influenced by the proportion of other additives apart from zinc.
White gold with nickel - nickel gold alloys have nice white colour. However, they are very hard, and therefore worse processable. They are not suitable for casting method thus white gold alloys with a content of nickel are not used in mass production. These white gold alloys have been used by goldsmiths for handmade jewellery. Thus made jewels are more durable thanks to their hardness and therefore gold with nickel is suitable for production of wedding or engagement rings.
The problem is that a customer is not able to recognize what kind of white gold alloy the jewel has been made of. Whether it has been made from an alloy with a yellowish tinge or an alloy which was brightly white. This is because the white gold jewellery is finally coated with a layer of rhodium. Rhodium is a platinum metal which has a beautiful white colour. The method of coating applied is called plating. It is a surface treatment such as gilding.
A wedding ring made of white gold with a yellowish tinge gets worn out in time as any other kind of jewellery. Progressively, the white rhodium 'scuffs' ,some scratches may appear and the original yellowish colour of gold is revealed. In practice, there are even some unreliable retailers who coat yellow gold with rhodium, in an attempt to sell it as white gold jewellery. Such a modified jewel is worn out in a short time and finally is neither yellow nor white.
So I end where I began. Should a golden jewel stay pretty white depend on what type of white gold alloy it has been produced of.