How do lignite and anthracite differ in carbon content?

Lignite and anthracite differ significantly in their carbon content, reflecting their different stages of coalification. As coal matures, volatile matter is expelled, causing the fixed carbon content to increase.1

• Lignite: As the first product of coalification, lignite contains approximately 60 to 70 percent carbon on a dry, ash-free basis.2
• Anthracite: As the most highly metamorphosed form of coal, anthracite contains 86 percent or greater fixed carbon on a dry, ash-free basis.3

Because of this higher carbon concentration, anthracite represents a more advanced stage of development, whereas lignite remains a lower-rank, geologically younger fuel.321