Precious metal

From Citizendium, the Citizens' Compendium

Precious metals are defined, variously, to be metals used for coinage or as monetary standards, or as scarce metals of high value. They tend to have high corrosion resistance and general durability. The first category invariably includes gold and silver; while copper and nickel are used for coinage, they are usually not considered precious.

In the second category, platinum is the most prominent member. Rhodium, rhenium and palladium are also often considered part of the group.