Diesel is known most commonly as the fuel for trucks, boats, buses, trains, machinery and other vehicles. Diesel, like gasoline, is made from crude oil. However, diesel and other fuels made from crude oil are different in several ways. Diesel is denser than gasoline. It is oilier and has a different odor than gasoline. At fueling stations, diesel pumps are clearly marked. Diesel fuel containers must be colored yellow, whereas gasoline comes in a red container. On a similar note, kerosene comes in a blue container. On a molecular level, gasoline and diesel are different. The chemical composition for gasoline is typically C9H20 whereas diesel is often C14H30. These are just a few ways diesel is distinct from other crude oil fuels. Diesel is a fossil fuel, meaning it is distilled from crude oil, or petroleum. Petroleum is mined from deep within the earth and, according to a 2005 article in Organic Chemistry written by Keith A. Kvenvolden, is composed of ancient biomass (the organic remains of plants and animals) that has been subjected to high heat and pressure. Diesel is created through a process called "fractional distillation," which separates certain parts of the crude oil.