Anthracite, also known as hard coal and black coal, is a hard, compact variety of coal that has a submetallic lustre. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.
Anthracite coal
An anthracite pile in Trevorton, Pennsylvania
Anthracite coal from Ibbenbüren, Germany
Anthracite from Bay City, Michigan
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is a type of fossil fuel, formed when dead plant matter decays into peat which is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times.
Bituminous coal, the most common coal grade
Coastal exposure of the Point Aconi Seam in Nova Scotia
Coal miner in Britain, 1942
Coal production of the world in 1908 as presented by The Harmsworth atlas and Gazetter