Anthracite Coal

Physical Properties

Hardness: 2.5-3.0 (Mohs); Color: Black to dark steel-gray; Luster: Sub-metallic to vitreous (glassy); Structure: Amorphous/foliated texture; Cleavage: Conchoidal fracture; Specific Gravity: 1.3-1.8

Formation & Geological History

Formed through the prograde metamorphism of bituminous coal. It involves the application of intense heat and pressure over millions of years, typically in areas of mountain-building (orogeny), dating from the Carboniferous period approx. 300 million years ago.

Uses & Applications

Primarily used as a high-grade fuel for residential and industrial heating due to its high carbon content and low impurities. Also used in water filtration systems and as a source for activated carbon.

Geological Facts

Anthracite is the highest rank of coal, containing 86%-97% carbon. It has the highest energy density of all coal types and burns with a short, blue, smokeless flame.

Field Identification & Locations

Field identification: Look for its distinct metallic luster and 'clean' feel compared to other coals (it doesn't soil fingers easily). Found in folded mountain belts like the Appalachian Mountains in Pennsylvania, USA.

Identified on: 4/20/2026

Mode: Standard