Natural oily flammable liquid consisting mainly of a complex mixture of hydrocarbons of various molecular weights and some other chemical compounds. The color of the oil is usually solid black. Has a specific smell.Oil is found together with gaseous hydrocarbons at depths of tens of meters to 5-6 km. the Density of oil, like other hydrocarbons, is strongly dependent on temperature and pressure. It contains a large number of different organic substances and therefore is characterized not by boiling, and an initial boiling point of liquids.