Precious Metals

A classification of metals that are considered to be rare and/or have a high economic value. The higher relative values of these metals are driven by various factors including their rarity, uses in industrial processes and use as an investment commodity.

Precious metals include, but are not limited to: gold, silver, platinum, iridium, rhodium and palladium.

Investing in precious metals can be done either by purchasing the physical asset, or by purchasing futures contracts for the particular metal. Another way to gain investment exposure to precious metals is to purchase shares in publicly traded companies that deal in the exploration or production of precious metals, such as a gold mining company.

From -  http://www.investopedia.com/terms/p/preciousmetal.asp