metamorphic

Anthracite Coal

High-rank coal (primarily Carbon, C)

AI-generated identification · may be incorrect

Hardness: 2.5-3.0; Color: Jet black to dark grey; Luster: Sub-metallic to vitreous (glassy); Structure: Amorphous/Non-crystalline; Cleavage: Conchoidal fracture; Specific Gravity: 1.3-1.8

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

Identified May 7, 2026More metamorphic →

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Physical properties

Hardness: 2.5-3.0; Color: Jet black to dark grey; Luster: Sub-metallic to vitreous (glassy); Structure: Amorphous/Non-crystalline; Cleavage: Conchoidal fracture; Specific Gravity: 1.3-1.8

Formation & geological history

Formed through the regional metamorphism of bituminous coal in sedimentary basins. It involves high heat and pressure over millions of years (often Carboniferous period, ~300-360 Ma) which drives off volatile matter and moisture.

Uses & applications

Primarily used for heating (domestic fuel), industrial processes requiring high carbon content, and sometimes carved for folk art or jewelry (jet-like).

Geological facts

Anthracite is the highest rank of coal, containing between 86% and 97% carbon. It burns with a short, blue, smokeless flame and is the cleanest burning form of coal.

Field identification & locations

Identify by its high luster, clean feel (does not soil fingers as much as softer coal), and tendency to break in curved, shell-like patterns. Common in the Appalachian region of Pennsylvania.