Bituminous coal or black coal is a relatively soft coal containing a tarlike substance called bitumen. It is of higher quality than lignite coalbut of poorer quality than anthracite. It was usually formed as a result of high pressure on lignite.
Bituminous coal is an organic sedimentary rock formed by diagenetic and sub metamorphic compression of peat bog material.
Bituminous coal has been compressed and heated so that its primary constituents are macerals vitrinite, exinite, and so on. The carbon content of bituminous coal is around 60-80%; the rest is composed of water, air, hydrogen, and sulfur, which have not been driven off from themacerals.
Bituminous coal is usually black, sometimes dark brown, often with well-defined bands of bright and dull material. Bituminous coal seams are stratigraphically identified by the distinctive sequence of bright and dark bands and are classified accordingly as either "dull, bright-banded" or "bright, dull-banded" and so on.
Bank density is approximately 1346 kg/m³ (84 lb/ft³). Bulk density typically runs to 833 kg/m³ (52 lb/ft³).