It has to do with the process of coalification.The degree of change a coal underwent as it matured from peat to anthracite can be termed as coalification. Coal is formed by the decay of plant matter.This decayed plant matter is called as peat and for this peat to become coal,it must be buried under sediments. read more
It is because of different composition found in coal they classified it into different types, based on carbon content(indicates calorific value), ash content(indicates waste generation), caking properties(used in steel making) and so on. read more
It is used for burning to supply heat and to make coal gas and coal tar. Charcoal is produced by slow heating of wood or other combustible substances in the absence of oxygen. It is also a black substance made by burning wood slowly in an oven with a little air, and can be used as a filtering material or as fuel or for drawing. read more
Most people are aware that one of the most famous stories coming out of the original Star Trek TV series is the one about the Enterprise finding and brining on board one of the original Voyager spacecraft. read more
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. read more