coal
combustible sedimentary rock composed primarily of carbon
sub-bituminous coal
lower grade of coal that contains 35–45% carbon
xyloid lignite
waste product generated by the mining of lignite
Vitrain
Lithotype of coal
lignite
type of fossil fuel; soft brown combustible sedimentary rock
fusain
type of fossil deposit
bituminous coal
often greasy, shiny, combustible organic sedimentary rock that consists of more than 75 per cent carbon by weight
metallurgical coal
grade of coal
anthracite
hard coal with a volatile component (gas) of less than 10 %