A member of the platinum group of metals, palladium is naturally white and has been rising in popularity with jewelers for decades. Palladium is whiter, 40% lighter, and 12% harder than platinum. When platinum was declared a strategic government resource during World War II, palladium was widely used as a substitute for rings and other jewelry. One of the most common metals found in white gold alloys, palladium is hypoallergenic, making it a practical substitute for those with nickel allergies. Over time, palladium will develop a patina similar to that of platinum jewelry. For many years, palladium was difficult to cast and many jewelers preferred other metals to it for jewelry applications despite its obvious benefits. Modern techniques have made casting palladium much easier and now palladium is seen with greater frequency in rings and especially earrings where its lighter weight allows for larger, more impressive pieces that don't weigh down the wearer's ears.