Exchange-Traded vs. Non-Exchange-Traded Commodity
A exchange-traded commodity is a commodity for which spot (cash) and futures markets are established and where official or settlement prices can be determined. Exchange-traded commodities include: wheat, corn, soybeans, oats, live cattle, cocoa, frozen orange juice, sugar, gold, silver, coal, electricity, gasoline, crude oil, diesel, ethanol, etc.
Conversely, a non-exchange-traded commodity is a commodity for which spot and futures markets do not exist and the only price information available comes from data provided by producers, consumers and traders. Non-exchange-traded commodities include: fresh flowers, melons, lemons, tomatoes, grapes, eggs, potatoes, asphalt, arsenic, borax, gypsum, asbestos, cement, carbon dioxide, rare earth metals, magnesium, manganese, silicon, rhodium, etc.
In fact, most commodities are not traded in exchanges. Only major ones are.