Because gold in its pure form is a relatively soft metal, we mix it with other precious metals to make it harder. That's how we get an alloy. Yellow gold is an alloy of gold, silver and copper, adding more silver than copper. Red gold has a higher content of copper than silver. In white gold, the alloy consists of gold, silver, palladium, copper and a small percentage of other metals, making white gold more silver-coloured than white.