Crude oil dripping from a glass stick into the neck of a glass container. The main part of the container (not seen) contains crude oil that has produced the brown fumes seen in the neck of the container. Crude oil is oil from the ground before it has been refined. It contains a varied mixture of hydrocarbons that are refined (separated) by heating. This process produces parts called fractions. Fractions that are obtained from crude oil include bitumen, fuel oil, lubricating oils, diesel, jet fuel, petrol, and petroleum gases. The fractions are used as heating, aircraft, and motor vehicle fuels, as industrial lubricants, and to make products such as plastics in the chemical industry.