Gold comes in several different colors, depending on which metals are mixed (alloyed) with it. Since gold alone is too soft to hold a form, gold is combined with other metals in order to make jewelry. There are 3 major colors that gold jewelry can be found in:

Yellow gold
Yellow gold is alloyed with both silver and copper, and is the most frequently used color of gold. Yellow gold is malleable, ductile, and generally non-corrosive.

White gold
White gold is alloyed with a large percentage of silver or other white metals. The percentage of gold used varies, depending on the amount of other metal used. White gold is highly reflective and will not tarnish. White gold is popular for use in engagement rings and wedding bands and substituted for platinum during World War II.

Rose gold
Rose gold is alloyed with copper and sometimes silver. The percentages are roughly one part copper to three parts 24-karat gold.