Anthracite is a dark black fossil fuel and the highest rank of coal. It is very hard, has a low moisture content, and has a carbon content of nearly 95%. When burned, anthracite can reach a very high temperature. Also, anthracite represents the oldest rank of fuel, with approximate ages of around 350 000 000 years.
The formation of anthracite not only takes a long time, but also requires especially high temperatures. The temperatures necessary for the development of anthracite coal are only possible on the borders of mountain belts. These regions are suitable because the process of building a mountain pushes sheets of rock over the layers where coal is being formed. This results in the layers containing coal being pushed down to depths of 8 to 10 km where the temperature can reach 300°C.
Anthracite can be used in household applications, primarily as a component of charcoal briquettes. As well, anthracite is used for space heating as it is one of the cleanest burning of all coal types - producing less smoke than other types. In addition to its clean burning properties, anthracite burns longer than wood, making it appealing to use in home heating stoves. Along with being clean and long burning, anthracite is used in these ways as it has a very high energy density - 7500 kcal/kg - the highest of any type of coal. Since so much energy is released when burned, this fuel is exceptional at heating up quickly and burning very hot.