(geology) A variety of coal that resembles a carbonaceous shale in outward appearance; it is fine-grained, black to brown, and tough. Also known as bitumenite; kerosine shale.

A variety of coat that resembles a carbonaceous shale in outward appearance. It is fine-grained, brown to black, and tough, and breaks with a conchoidal or subconchoidal fracture. Torbanite is synonymous with boghead coal and is related to cannel coal. It is derived from colonial algae identified with the modern species of Botryococcus braunii and antecedent forms. High-assay torbanite yields paraffinic oil, whereas low-assay material yields asphaltic oil. See also Coal.