Platinum is very rare, only making up 0.005 PPM (parts per million) of the Earth’s crust. Platinum is associated with prestige- in fact, King Louis XV of France declared it the only metal fit for a king!
Palladium is a rare precious metal commonly used to create white gold. Palladium was first issued as currency by Sierra Leone in 1966. Because of its rarity, palladium is highly valued and often reserved for very special commemorative coins.