In its natural state gold come in varying shades of yellow. Relatively pure when initially mined, gold is usually alloyed with copper, zince, and/or silver when used in jewelry making.
A specific color of gold when its in its natural state.
Yellow gold is gold that has been alloyed with a mix of 50% copper and 50% silver.
The natural color of pure gold as well as the color of karat gold when alloyed with certain metals.