Nickel, palladium, copper, and silver are alloys added to create different colors and strength to gold jewelry. Copper creates gold and pink tones. Nickel is added to produce a white-grey color, silver is added to produce a greenish color. Palladium, in amounts of 10-12% are added to make white gold, which is heavier, stronger and more expensive!

The definition of alloy:

1. A homogeneous mixture or solid solution of two or more metals, the atoms of one replacing or occupying interstitial positions between the atoms of the other: Brass is an alloy of zinc and copper.

2. A mixture; an amalgam: “Television news has . . always been an alloy of journalism and show business” (Bill Moyers)

3. The relative degree of mixture with a base metal; fineness.

4. Something added that lowers value or purity.

Colored gold alloys are just as "real" as their golden colored counterparts. Since pure gold is generally too soft to be used for jewelry, other metals are nearly always added to it, no matter which color is desired.

Making alloys isn't as simple as it might sound. Jewelers must consider how metals will react with each other. Adding too much of one metal or another can make the mixture brittle, too hard, or difficult to work with. Other ingredients might make the mix too soft.

Metallurgists must fine-tune their recipes to find combinations that produce pleasing metals that are durable and can be successfully worked into pieces of jewelry.”

For most uses of gold the pure metal is too soft on its own and is therefore hardened by the addition of alloying elements, copper, silver, nickel, palladium and zinc. Gold is of course yellow and the various colours seen such as red, white and green are simply alloys of gold. The final colour is dependent on the ratios and type of alloys added.”

Gold is yellow, copper is reddish, and all other metals are a silvery grey in colour. There are however gold alloys, that is mixes of differing metals, that appear grey/white.

White gold (alloy) became popular around 1920 as a substitute for platinum, as platinum was quite expensive. Simply mixing a white and yellow metal together will not produce a colour in the same way that mixing paint does. The most common metal used to 'bleach' gold is nickel which is both inexpensive and provides a good platinum look-alike in 18ct alloys.”

Many new alloys are coming to market, most of which rely on manganese additions as the main whitener. Some are palladium-free and others are low palladium alloys. Chromium and iron are also be used as whiteners. They tend to be hard and more difficult to process.”

18 carat and 22 carat gold alloys are almost completely resistant to chemical attack and 9ct alloys are much less resistant. Nine carat alloys can dull or even blacken from exposure to chemicals in the atmosphere, and might discolour in contact with household chemicals. 9ct chain is usually finished with a deeper yellow 18ct or 22ct coating by manufacturers, which is why the bright finish on a new 9ct chain gradually tones down to match other jewelery that you wear on a daily basis.