Oil Deposit

Oil deposits are a type of "ore" that spawns in large veins. You can use an Oil Reservoir Detector to find these easiest.

Uses
The oil deposit is a deposit which has oil (hence the name). The oil can be extracted by pumping it out with oil derricks or pumpjacks. It will yield crude oil, which can be boiled and then refined in the oil refinery for petroleum products.

Trivia

 * In older versions of the mod, you could just stack all of the deposits in a boiler and skip the pumping process, but it would yield a lot less oil.
 * This was likely removed due to the abilities certain tools got.