Bituminous rank and defining characteristics | Credit: Kentucky Geological Survey, University of Kentucky

Bituminous coal is a medium-rank coal with 45-86% carbon content, intermediate between sub-bituminous coal and anthracite. It appears as a dense, black sedimentary rock with a shiny luster and distinctive banding or layering, characterized by the presence of bitumen (mineral tar) that causes the coal to soften, swell, and form a sticky mass when heated.

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