Examples are coffee, tin, sugar, wool, rubber, silver and cocoa.
Commodities are bought and sold on a commodities exchange by dealers and commodity brokers or traders. The materials' homogeneity, fast communications and an efficient system of quality grading and control mean that commodities can be traded without an actual transfer of the goods. Commodity prices swing more violently than prices of manufactured goods. Consumers would prefer more stable prices, too. These are agreements between producers and consumers which try to stabilize prices using buffer stocks and export or production quotas.