Anthracite is a hard, compact variety of mineral coal that has a high luster. It has the highest carbon content, the fewest impurities, and the highest calorific content of all types of coal, which also include bituminous coal and lignite.
Anthracite is the most metamorphosed type of coal (but still represents low-grade metamorphism), in which the carbon content is between 92.1% and 98%. Anthracite ignites with difficulty and burns with a short, blue, and smokeless flame.