A few words about 'white gold.'

What you are actually looking at when admiring those bright, shiny white gold rings in a jewellery shop is not actually gold at all, but the rhodium that is plated onto it.

It is an industry-wide practice to plate all white gold with rhodium, which is much brighter and whiter. Real white gold has a touch of dark yellow/green to it, which is hardly surprising when you consider that gold is a rich yellow colour, and if your ring is 14K (for example) then 14 parts out of 24 (24K is pure gold) are yellow.

Given this fact, it is obvious that the end result cannot be completely white, hence the rhodium plating.

Plating always wears off over time, especially where the bands rub against each other (which they do, even when the ring is snugly in place on your finger). This is why jewellers commonly recommend re-plating white gold rings every few years.

If you have ordered a ring containing white gold it will automatically be rhodium-plated, unless you stipulate otherwise.

If you do not want the inconvenience and expense of getting your ring re-plated every year or so simply to maintain its looks, or are curious about actual white gold, keep reading.

WHITENING AGENTS

There are 3 metals that are generally used to whiten gold : nickel, silver and palladium.

Nickel is the one commonly used in the US. It is a more effective whitening agent and makes for harder alloys, but unfortunately it causes allergic reactions in roughly 17% of women and 3% of men. Allergy issues are the reason why the EU has strict rules about the presence of nickel in jewellery.

Silver is a less effective whitening agent, and makes for softer alloys. The allergy issues associated with silver are negligible.

Palladium is the whitening agent of choice in the EU and many other countries. Being much more expensive than either nickel or silver, palladium white gold is somewhat more expensive than the alternatives. The allergy issues associated with palladium are negligible.

ABOUT GOLD ALLOYS

The element gold (Au) is a rich yellow colour, and it and copper are the only coloured metals. All others are grayish/white-ish in colour.

Pure gold is designated as being 24K. An alloy that is designated as being (for example) 18K contains 18 parts of gold and 6 parts of other metals (to make a total of 24 parts). These 'other metals' include zinc, copper, nickel, silver, palladium, platinum, iron, cadmium and aluminium.

In general, the greater the proportion of gold in an alloy the more yellow it will appear. Thus 10K silver white gold can be quite white, while 14K silver white gold is actually known as 'green' gold, and no-one uses silver in 18K since the result would be an off-yellow colour.

Nickel white gold alloys are varying shades of gray.

Palladium white gold can vary from light gray to (relatively) dark gray, and even be a brownish colour.