precious metal is a rare, naturally occurring metallic chemical
element of high economic value, which is not radioactive
(excluding natural polonium, radium, actinium and protactinium).
Chemically, the precious metals are less reactive than most
elements, have high lustre, are softer or more ductile,
and have higher melting points than other metals. Historically,
precious metals were important as currency, but are now
regarded mainly as investment and industrial commodities.
silver, platinum, and palladium each have an ISO 4217 currency
The best-known precious metals are the coinage metals gold
and silver. While both have industrial uses, they are better
known for their uses in art, jewelry and coinage. Other
precious metals include the platinum group metals: ruthenium,
rhodium, palladium, osmium, iridium, and platinum, of which
platinum is the most widely traded.