You might find yourself asking what a commodity is. Not all products are considered commodities; in fact, a painting is not a commodity, why? each painting is unique. To be considered as a commodity, items or products must be uniform and one portion/individual will serve the same purpose as another. However, you can observe some differences. Differences in composition and shipping costs give rise to different prices and markets. Commodities are traded in either a spot market or a future market.
In a spot market, commodities are immediately traded in exchange for some goods or cash. A typical example is when you buy jewelry. You give the money and in return, the seller gives you the jewelry. In a future market, the good itself is not traded. A contract is formed, and the commodity will be bought/sold at a certain future date, at a certain price.