sedimentary

Anthracite Coal

Anthracite (Highly Metamorphosed Coal)

AI-generated identification · may be incorrect

Hardness: 2.5-3.0; Color: Black or dark iron-black; Luster: Sub-metallic to vitreous (glassy); Crystal Structure: Amorphous; Fracture: Conchoidal; Specific Gravity: 1.3-1.7

Hardness: 2
Color: Black or dark iron-black
Luster: Sub-metallic to vitreous (glassy)

Identified May 2, 2026More sedimentary →

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Physical properties

Hardness: 2.5-3.0; Color: Black or dark iron-black; Luster: Sub-metallic to vitreous (glassy); Crystal Structure: Amorphous; Fracture: Conchoidal; Specific Gravity: 1.3-1.7

Formation & geological history

Formed through the burial and heating of plant matter (peat) over millions of years. Anthracite is the highest grade of coal, having undergone low-grade metamorphism that removes most volatile matter and moisture.

Uses & applications

Primarily used as a residential and industrial fuel due to its high energy density and low smoke production. Also used in water filtration systems and as a carbon source for steel production.

Geological facts

Anthracite has the highest carbon content of all coals (86% to 98%). It is the oldest and hardest coal, often referred to as 'hard coal' or 'black diamond'.

Field identification & locations

Identify in the field by its high luster, deep black color, and the fact that it does not soil fingers like softer coals. It is commonly found in the Appalachian region of Pennsylvania, USA, where it accounts for nearly all of the country's anthracite resources.