Base Oil is the name given to lubrication-grade oils initially produced from refining crude oil (mineral base oil) or through chemical synthesis (synthetic base oil). All lubricants contain a base oil. It serves as the foundation of the lubricant before it is blended with additives or a thickener in the case of grease. It is typically defined as oil with a boiling point range between 550 and 1050 °F, consisting of hydrocarbons with 18 to 40 carbon atoms. This oil can be either paraffinic or naphthenic in nature depending on the chemical structure of the molecules.