Shades of gold: a spectrum of colors

Pure gold is too soft to make jewelry with, so other metals have to be mixed in to make it strong enough to wear on a regular basis. Interestingly, combining other metals with gold can alter its color. You may already be familiar with white and rose, but did you know that gold in fact comes in a full spectrum of colors?

Here is a comprehensive guide to the various shades of gold available. Keep in mind that all of the below mixtures assume 75 percent pure gold, thereby making them 18-karat. Lower karat grades will have different ratios.

• Yellow: 12.5 percent silver and 12.5 percent copper make the closest approximation to the color of 24-karat gold.

• White: gold is mixed with metals such as palladium, copper, zinc and silver, and then plated in rhodium. This metal will have to be re-plated periodically to conserve its color.

• Rose: gold is mixed with 20 percent copper and five percent silver.

• Red: similar to rose gold, but only copper is used to make the alloy.

• Black: the same mixture as white gold but plated with black rhodium.

• Green: also known as electrum, to get this color, gold is mixed with silver.

• Blue: known as an intermetallic alloy, in this case gold is mixed with iron or cobalt.

• Purple: also an intermetallic alloy, in this variation, gold is mixed with aluminum.

While all shades of gold can be beautiful in their own right, some types are more suitable for jewelry than others. It’s therefore best to speak to an experienced jeweler before making a purchase.