noble metals

The noble metals include gold, silver, mercury, and the platinum group (including palladium, iridium, rhodium, ruthenium, and osmium). The term "noble metals" refers to those metals that are highly resistant to chemical reaction or corrosion, meaning that they will not easily dissolve in a solvent or rust. All other metals are called "base" metals and will more easily undergo chemical changes.

The term "noble metals" has its origins in ancient alchemy, the practice of attempting to transform base metals into gold. "Noble metals" is not synonymous with "precious metals," (a term used to describe expensive metals used for making coins, jewelry, and ornaments) although gold, silver, and platinum are both noble and precious metals.