Palladium is a soft silver-white metal that resembles platinum. It is the least dense and has the lowest melting point of the platinum group metals. It is soft and ductile when annealed and is greatly increased in strength and hardness when cold-worked. Palladium does not react with oxygen at standard temperature and thus does not tarnish in air.
Monel, any of a group of nickel-copper alloys, first developed in 1905, containing about 66 percent nickel and 31.5 percent copper, with small amounts of iron, manganese, carbon, and silicon. Stronger than pure nickel, Monel alloys are resistant to corrosion by many agents, including rapidly flowing seawater. They can be fabricated readily by hot- and cold-working, machining, and welding.
Shakudo is the Japanese term for a low gold content alloy which usually consists of between 2-7% gold and the rest copper. Sometimes small amounts of other metals are added. The usual alloy used is a 3% gold alloy/rest copper. The Shakuduo I use is copper with 4% fine gold added which will patinia to a rich black color
Shibuichi is an old Japanese technique of combining primarily copper and silver in varying proportions depending on the color desired. The silver percentage can range from 2% to 60% or more. These percentages are calculated for a specific color result based on centuries of experience. My Shibuichi is copper with 14% fine silver added which will patinia to a blue green color