A thick blob of unrefined oil. Can be refined with hide to make gasoline.
— In-game Description

Oil is a resource harvested from deposits in the ocean and in the cold northwest of The Island using the Metal Pick or at an oil vein in the desert using the Oil Pump. Though the ocean is quite dangerous, Oil is required to produce jerky from meat in the Preserving Bin, to produce Gasoline with Hide in the Refining Forge or Industrial Forge, and to create high level building materials and weapons. It is generally advised to use Lazarus Chowder and a tamed aquatic dinosaur to reach underwater caves. The Trilobite and Oil Jug Bug are also a source of Oil, providing an alternative to the underwater caves and ocean floor. The eggs of the Hesperornis render into Oil and a protein substance. The Tusoteuthis is a source of Oil through its ink. The Dung Beetle is inherently capable of producing Oil and Fertilizer.