A precious metal is a rare, naturally occurring metallic chemical element of high economic value. Chemically, the precious metals tend to be less reactive than most elements. They are usually ductile and have a high luster. Historically, precious metals were important as currency but are now regarded mainly as investment and industrial commodities. Gold, silver, platinum, and palladium each have an ISO 4217 currency code.

The best known precious metals are the coinage metals, which are gold and silver. Although both have industrial uses, they are better known for their uses in art, jewelry, fine 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. The demand for precious metals is driven not only by their practical use but also by their role as investments and a store of value.

Whereas a metal is deemed to be precious if it is rare, the status of a precious metal can also be determined by high demand or market value. Precious metals in bulk form are known as Bullion and are traded on commodity markets. Bullion metals may be cast into ingots or minted into coins. The defining attribute of bullion is that it is valued by its mass and purity rather than by a face value as money.

The level of purity varies from issue to issue. “Three nines” (99.9%) purity is common. The purest mass-produced Bullion coins are in the Canadian Gold Maple Leaf series, which go up to 99.999% purity. A 100% pure Bullion is nearly impossible: as the percentage of impurities diminishes, it becomes progressively more difficult to purify the metal further. Other Bullion coins (for example the British Sovereign) show neither the purity nor the fine-gold weight on the coin but are recognized and consistent in their composition.

Assortment of Precious Metals