An alloy of gold with a high percentage of silver or any of several other white metals, the percentage of gold varying depending on the other metal used.
It is of pale gold colour. The term is sometimes applied to the ancient electrum. Before the use of platinum or palladium, white gold was often used as a setting for diamonds, being highly reflective and, unlike silver, not subject to tarnish.
From: An Illustrated Dictionary of Jewelry, autor: Harold Newman, publishers: Thames and Hudson