Gold in its purest form is a warm, yellow or ‘Gold’ colour that everyone is familiar with but is essentially a soft metal, unable to withstand the wear and tear experienced by jewellery items. In order to improve the durability of Gold for use as jewellery it is common to mix Gold with harder metals to produce an alloy suitable for the job.
The ratio of the Gold and other metal content of an alloy dictates the ‘carat’ of the Gold produced. An alloy that is 75% Gold would be classed as 18 Carat; a more hardwearing alloy with only 37.5% Gold content would be 9 Carat.
It has long been the case that Gold alloys for jewellery were produced to resemble the colour of pure Gold as closely as possible. Hence the most common metals used in Gold alloys have been Copper and Silver for colour and strength.
Availability of rare and expensive ‘White’ metals such as Platinum and Palladium in the early 20th Century developed a demand for a new, paler look for expensive jewellery items. This demand influenced the Gold jewellery market and led to the development of ‘White’ Gold alloys.
White Gold alloys have been developed over the years by incorporating Nickel, Zinc and Palladium to produce the popular bleached colour effect but not all of these ‘ingredients’ are considered safe by modern standards. Many people are allergic to Nickel and, whilst it is still commonly used as an element of White Gold in many parts of the world, including the USA, the production of White Gold with Nickel is now prohibited in Europe. Palladium has generally replaced Nickel in the production of White Gold jewellery in Europe.
Brilliantly reflective White Gold is very popular in association with diamonds as it amplifies the sparkle and lustre of the stones. Such properties are difficult to produce from a White Gold alloy and are increasingly provided by means of Rhodium plating. Rhodium is rare, extremely expensive and difficult to work as it is a very brittle metal, making it unsuitable for use within an alloy but it works very well as a plating material, producing a white, mirror like finish similar to a Chromium plated surface. The negative aspect of Rhodium plating is that, over time, the plating can wear and reveal the original Gold colour beneath the plating.
In summary, White Gold is still Gold, whether the colour is achieved by alloying with bleaching effect metals or by plating. White Gold items will still bear standard Gold Hallmarks specifying the Carat or Gold content of the item.