Product Description

Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon along with variable quantities of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.

Throughout history, coal has been a useful resource for human consumption. It is primarily burned as a fossil fuel for the production of electricity and/or heat, and is also used for industrial purposes such as refining metals. Coal forms when dead plant matter is converted into peat, which in turn is converted into lignite, then anthracite. This involves biological and geological processes that take place over a long period of time.