As we are all aware, the purest form of gold is always golden in colour and in its purest form it is widely termed as 24 karat gold. By alloying gold with other elements in various proportions, different gold colours can be obtained. White gold is an alloy of natural gold with such white metals as palladium, zinc, silver, nickel or manganese, which are often plated with rhodium to make it appear whiter. White gold is therefore not true white like platinum, which is in itself a white metal. The purity of white gold is also determined in karat.
The definition of white gold is often misinterpreted as many people are of the opinion that white gold is a shimmering white metal. In the jewellery industry, the term white gold is used very loosely to determine karat gold alloys that are accompanied with a whitish hue. The rhodium plating is often misinterpreted to be the actual colour of white gold. The truth is, without the rhodium plating, white gold may appear a dull brown, pale yellow, gray or even a pale rose. Rhodium plating is basically an enhancing element used to give white gold its shiny effect.
History and Popularity of White Gold:
The popularity of white gold reached its peak during the 1920s. It became a beautiful substitute for platinum, which is a more expensive metal. Moreover, platinum could not be easily moulded into jewellery and is rather a tough metal to work with. Three patents involving the various methods of white gold alloying were passed in the year 1920. The different processes involved the use of different metals in order to arrive at the desired white color.
Compositions of White Gold Alloys:
White gold commonly comes in 10, 14 or 18 karats but is also available in other grades. In short, it is available up to 21 carats. As mentioned, the karat weight system of white gold is the same as yellow gold. The amount of gold used in both is the same with only the alloy being different. For example, an 18 karat yellow gold is composed of 75% gold and the rest 25% constitutes other metals like zinc and copper. Similarly 18 karat white gold constitutes 75% gold and 25% other metals like nickel, silver or palladium. 14 karat white gold on the other hand comprises of 58% gold, while 10 karat comprises of 41% gold. This implies that lower the karat, lesser will be the quantity of gold in the alloy.
White gold is basically a composition of 90% gold and 10% other elements. Copper is often added to improve malleability. In the jewellery industry, the common alloys used are: gold-palladium-silver and gold-nickel-copper-zinc. The primary bleaching agents for gold are nickel and palladium whereas the secondary bleaching agent is considered to be zinc. Zinc is basically used to enhance the colour of copper. The top two gold bleachers are considered to be palladium and nickel whereas zinc and silver are considered to be the next best bleaching elements.
The gold-nickel alloys are widely popular due to their hardness and strength. Apart from the fact that they are used in making nose-pins, finger rings and earrings, they are particularly good for gemstone settings. However, owing to the phenomenon called fire-cracking, jewellers find it hard to work with it. In addition, nickel has certain disadvantages too. They not only cause allergic reactions such as dermatitis, but also has carcinogenic properties. Usually one out of eight people suffer from allergic reactions of nickel. Owing to this many countries have banned the use of nickel.
It must be understood that the term white gold is used to define a range of colours like pale yellow, light brown, pale pink, etc. It is rhodium plating which not only enhance the colour and make it appear whiter but also enhance the look of the white gold. Rhodium plating is necessary when copper is added to the alloy mix as it darkens the colour. Hence, it is often plated with rhodium to make it appear whiter and augment its appearance. However, in order to retain the colour and lustre, rhodium plating should be done every few years. It is basically inexpensive and most of the jewellers offer it for free.