Is one "whiter" or more brilliant than the other?
In terms of hardness, are they comparable? And is palladium as dense as PT?
Palladium itself has been used as a precious metal in jewelry since 1939, as an alternative to platinum or white gold. This is due to its naturally white properties, giving it no need for rhodium plating. It is slightly whiter, much lighter and about 12% harder than platinum. Similar to gold, palladium can be beaten into a thin leaf form as thin as 100 nm (1/250,000 in). Like platinum, it will develop a hazy patina over time. Unlike platinum, however, palladium may discolor at high soldering temperatures, become brittle with repeated heating and cooling, and react with strong acids.
Palladium is one of the three most popular metals used to make white gold alloys. (Nickel and silver can also be used.) Palladium-gold is a more expensive alloy than nickel-gold, but it's naturally hypoallergenic and holds its white color better.
When platinum was declared a strategic government resource during World War II, many jewelry bands were made out of palladium. As recently as September 2001, palladium was more expensive than platinum and rarely used in jewelry also due to the technical obstacle of casting. However the casting problem has been resolved, and its use in jewelry has increased because of a large spike in the price of platinum and a drop in the price of palladium.Prior to 2004, the principal use of palladium in jewelry was as an alloy in the manufacture of white gold jewelry, but, beginning early in 2004 when gold and platinum prices began to rise steeply, Chinese jewelers began fabricating significant volumes of palladium jewelry. Johnson Matthey estimated that in 2004, with the introduction of palladium jewelry in China, demand for palladium for jewelry fabrication was 920,000 ounces, or approximately 14% of the total palladium demand for 2004 - an increase of almost 700,000 ounces from the previous year. This growth continued during 2005, with estimated worldwide jewelry demand for palladium of about 1.4 million ounces, or almost 21% of net palladium supply, again with most of the demand centered in China. The popularity of Palladium jewelry is expected to grow in 2008 as the world's biggest producers embark on a joint marketing effort to promote Palladium jewelry worldwide