Anthracite Coal

Physical Properties

Hardness: 2.5–3 on Mohs scale; Color: Black to steel-grey; Luster: Sub-metallic to vitreous; Structure: Amorphous (non-crystalline); Fracture: Conchoidal; Specific Gravity: 1.3–1.8

Formation & Geological History

Formed through the intense metamorphism of peat and lower-grade coal layers under high heat and pressure, typically during mountain-building events (orogeny). Most is 300-360 million years old (Carboniferous period).

Uses & Applications

Primarily used for heating and industrial filtration. Historically used for domestic fuel and steam generation. Higher grades are used in water purification and as a recarburizer in steel production.

Geological Facts

Anthracite is the highest grade of coal and contains the highest percentage of fixed carbon (86-97%). Unlike lower-grade coal, it burns with a blue, smokeless flame and is very clean to the touch.

Field Identification & Locations

Identify in the field by its high luster (shiny appearance), black streak, and conchoidal (shell-like) fracture. It is much harder and cleaner than bituminous coal. Commonly found in Pennsylvania, USA, and parts of the UK and China.

Identified on: 4/26/2026

Mode: Standard