Gold is a yellow metallic element. Pure gold is too soft to be used for making jewelry. To increase its strength it is mixed with other metals to form alloys. The metals so used alter the color of gold producing various shades of yellow, white and pink.
There actually exists no such thing as White Gold. When jewelers speak of white gold they refer to gold alloys that are white in color. White Gold was originally produced to imitate platinum.
White gold is essentially an alloy of gold with at least one white metal. Alloy simply refers to a mixture of two or more metals. Mixing a white and a yellow metal doesn’t, as it seems, produce a pale yellow metal. Alloying alters the atomic structure of the metal which in turn alters the reflectivity of light of different wavelengths giving the desired color to the metal. The metals used to bring the white color of gold are nickel, zinc and palladium
White gold usually comprises of gold and nickel due to inexpensiveness of nickel. It makes white gold affordable. But a major disadvantage is that it might cause skin allergies to some. Palladium is considered to be an ideal metal for the production of white gold. But it, just like nickel, is not devoid of disadvantage, as it is expensive and makes manufacturing difficult as palladium has a high melting point.
Other whiteners include silver, platinum, chromium, cobalt, tin, zinc and indium.
Like yellow gold, white gold is also measured in carats. Owing to its resemblance to Platinum and the relative inexpensiveness, White Gold receives its world wide acceptance in various forms of jewelry.