Coal the heat and pressure of deep burial causes the loss of water, methane and carbon dioxide and an increase in the proportion of carbon. Thus first lignite (also called "brown coal"), then sub-bituminous coal, bituminous coal, and lastly anthracite (also called "hard coal" or "black coal") may be formed. The wide, shallow seas of the Carboniferous Period provided ideal conditions for coal formation, although coal is known from most geological periods. The exception is the coal gap in the Permian–Triassic extinction event, where coal is rare. Coal is known from Precambrian strata, which predate land plants—this coal is presumed to
Cannel coal yellow flame and little ash. The modern Lycopodiopsida relatives of these lycopsids (scale trees), with their similar high oil content, high surface area spores, are the source of highly flammable lycopodium powder. Cannel coal is also lower in fixed carbon than typical bituminous coal. It includes various amounts of vitrinite and inertinite. Analytically, cannel coal consists of micrinites, macerals of the exinite group, and certain inorganic materials. Cannel coal Cannel coal or candle coal, is a type of bituminous coal, also classified as terrestrial type oil shale. Due to its physical morphology and low mineral content cannel coal is considered