Recently I read an article in which a "jeweler" had sold a rhodium plated yellow gold ring to a customer and told them it was "white gold". Apparently the "jeweler" didn't actually know that there was such a thing as white gold, hence my quotes around the word jeweler as I would hesitate to call anyone a jeweler who didn't know what white gold actually was. Unfortunately, the amount of misinformation in my trade is staggering and it only seems to get worse as technology advances each year. If you're not willing and able to keep up with things you simply shouldn't be in this business.
So let's talk a bit about white gold. All gold that isn't 24k (or pure) gold is an alloy of pure gold with other metals. Usually this is copper and silver. White gold however is a different story as you're taking a yellow metal and trying to make it into something it isn't. In the past, nickel was added to the metal to make it white. The word white here is a relative term as most of it didn't actually come out white, but yellowish white. It was then rhodium plated (rhodium is a member of the platinum metals group) to actually make it look as white as possible. The problem with plating the metal, however, is that the plating wears off and one day you look down at your ring and it's suddenly two different colors. White gold with nickel also tended to not cast well and many white gold castings start to show stress cracks over time.
The other issue with nickel white gold is that many people have an allergy to nickel which shows up as skin rashes and inflammation around any area exposed to the metal. Honestly, some people have allergies to gold as well but it is far, far less common than nickel allergies. Nickel in jewelry has actually been banned in many countries in Europe.
A number of years ago, after complaining incessantly to my metal supplier, they located an old formula for a palladium white gold recipe which I experimented with and they soon afterwards began producing for sale. This is a completely nickel free metal. It is also not the pure white color of platinum but rather has a somewhat grayish tone to it. It is easier to work with, does not seem to have the brittleness problems associated with the nickel white gold and is a nice alternative to nickel white gold. Recently more white gold options have come into the marketplace due to technological advances in metallurgy and the ability to use computers to analyze different formulations. But most of them still are either using palladium or nickel in them as the basic whitening agent.
Next posting will be on platinum. Pictured is the Philippe ring. The center is sandblasted 18k palladium white gold, the borders are 950 platinum.