If gold is naturally yellow, how is white gold made?
One of the most striking features of gold is undoubtedly its naturally yellow coloration. However, if this element occurs in nature with this hue, then how are white gold jewelry produced? What's more, if this material is also gold, why does it have a silver tint?
Who explains these questions is Sarah Stone of Today I Found Out, but before checking the answers, how about getting to know gold a little better and finding out how it is used by goldsmiths? In its purest form, this element is known as 24 carat gold - which, by the way, although valuable, is too malleable to be used in jewelry making.
For this reason, to make rings, chains and other parts, it is necessary to create a metal alloy with other materials to make it more resistant. Thus, considering that 24 carat gold is the purest - and that it consists of 24 parts of the element - when we talk about an 18 carat jewel, for example, we refer to a piece consisting of 18 parts of gold and six parts of other material, and the same applies to 14 carat jewelry.
According to Sarah, the choice of materials that will be used to create the alloys depends on the outcome the goldsmith wants to achieve. So for jewels that will have gold coloration, it is quite common that metals such as zinc and copper are employed. Now, as you may have already deduced, we come to the question of white gold.
To make white gold jewelry, goldsmiths typically employ metals such as manganese, silver and palladium. Nickel, which has always been widely used due to its low cost, has begun to fall into disuse because it is a material that can provoke allergic reactions. However, although the pieces produced with these materials have a silver color, their brightness is not that vibrant, and they still have a slight yellowish hue.
So, to get the showy jewels we know, goldsmiths wash the pieces with a layer of rhodium, an element of the same platinum group that, besides having a beautiful silver shine, is extremely durable. With use, this material will eventually wear out and, depending on the alloy composition used in jewelry making, the yellowish tone of the piece begins to appear again - which can easily be resolved with another rhodium plating.
Yes ... the cart above is white gold!
According to Sarah, just as it is possible to make yellow and white gold jewelry, there is also the possibility of producing pieces of other colors. Therefore, to make a rose gold earring, for example, simply increase the proportion of copper in the alloy. However, if you want to get a green tint, just add more zinc, silver and copper to the mix.
Already to get a piece of bluish gold, just add some Indian or gallium, and, according to Sarah, it is even possible to make jewelry made of dark gold, bathing the pieces with black rhodium.