Bitumen

Bitumen is a refinery product from Heavy Oil. It, still, retains an appearance similar to Crude Oil. It is very thick.

Obtaining
Heavy oil refinement gives 300mb per 1,000mb.

600mb of bitumen can be extracted from 16 Tar Sand blocks, but you require at least 400mb to start (resulting in 1,000mb of bitumen).

It can also be produced by liquefying oil tar.

Uses
Bitumen has little uses in itself, but it can be solidified into oil tar at the highest efficiency with 100mb per blob of tar.

1,200mb of it can be mixed with 2,400mb of steam to turn it back into Crude Oil (1,000mb). Also results in 200mb of Petroleum Gas.

The only actual use itself has is to make Asphalt, which isn't extremely useful either except for realistic-looking roads or other aesthetic purposes. It takes 1,000mb of bitumen, 2 gravel, and 6 sand to make 16 Asphalt blocks.