White gold is an alloy of gold and at least one white metal, usually nickel, manganese or palladium. Like yellow gold, the purity of white gold is given in karats. To enhance the whiteness, almost all white gold is plated with rhodium, a shiny, white metal which is extremely hard. Depending on the amount of wear to a piece of jewelry, over time this rhodium plating may wear off, revealing the original metal color