What is anthracite known as?

Anthracite is known as a type of coal, specifically the highest rank of coal, characterized by its high carbon content and low moisture levels. It is known for burning the cleanest among all coal types, providing a high heat output and producing little smoke. Due to its coal formation properties, anthracite forms under high pressure and temperature compared to other coal types, like bituminous or lignite, which makes it very hard and shiny.

The other options do not categorically describe anthracite. Soft coal typically refers to lignite or sub-bituminous coal, which is lower in carbon content and energy efficiency. Bituminous coal is another common form that has a lower carbon ratio than anthracite. Charcoal, meanwhile, is a completely different material made from carbonized organic materials, generally wood, and is not related to the geological formation of coal. Thus, identifying anthracite as a type of coal is the most accurate characterization.