sedimentary

Anthracite Coal

Anthracite coal (High-rank coal)

Mohs hardness: 2.5-3.0; Color: Black to dark grey; Luster: Sub-metallic to vitreous (glassy); Structure: Amorphous/microcrystalline; Specific Gravity: 1.3-1.8; Fracture: Conchoidal

Hardness: 2
Color: Black to dark grey
Luster: Sub-metallic to vitreous (glassy)

Identified July 3, 2026More sedimentary →

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Physical properties

Mohs hardness: 2.5-3.0; Color: Black to dark grey; Luster: Sub-metallic to vitreous (glassy); Structure: Amorphous/microcrystalline; Specific Gravity: 1.3-1.8; Fracture: Conchoidal

Formation & geological history

Formed through the burial and heating of plant matter over millions of years (Carboniferous period), a process called coalification, where high pressure and heat concentrate carbon levels to 86-97%.

Uses & applications

Used primarily for heating, water filtration, and industrial fuel. It is also used for carving decorative objects due to its ability to take a high polish.

Geological facts

Anthracite is the highest rank of coal and contains the least impurities. It burns with a clean, blue flame and produces more heat per unit than lower-grade coals like bituminous coal or peat.

Field identification & locations

Identified in the field by its high luster, deep black color, and the fact that it does not leave a dirty residue on hands compared to other coals. Often found in geologically folded mountainous regions like the Appalachians.