Palladium is less expensive because it is not as dense as other metals. Palladium is a platinum-group metal, and is similar to platinum in color and purity but is not as heavy. Palladium weighs approximately the same as 9-karat gold.
Palladium has a bright white color and is 95 percent pure, like platinum. The metal does not require rhodium plating, as white gold does, and is also hypoallergenic, so it is suitable for those with allergies to nickel. It is often used to make white-gold alloys. Palladium has been used in jewelry since 1939 and was first discovered in 1803.