sedimentary

Anthracite Coal

Anthracite (Carbon rank)

Hardness: 2.5-3 (Mohs), Color: Black or dark grey, Luster: Sub-metallic to vitreous, Structure: Amorphous/microcrystalline, Cleavage: Conchoidal fracture, Specific gravity: 1.3-1.8

Hardness: 2

Identified July 3, 2026More sedimentary →

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Physical properties

Hardness: 2.5-3 (Mohs), Color: Black or dark grey, Luster: Sub-metallic to vitreous, Structure: Amorphous/microcrystalline, Cleavage: Conchoidal fracture, Specific gravity: 1.3-1.8

Formation & geological history

Formed through the burial and heating of plant matter (peat) under intense pressure and temperature over millions of years (Carboniferous era). It represents the highest grade of coal metamorphism.

Uses & applications

Historically used for domestic heating and steam generation; currently used in water filtration, residential heating in specific regions, and as a carbon source in steel manufacturing.

Geological facts

Anthracite is the cleanest burning coal, possessing the highest carbon content (over 86%) and the lowest impurities among all ranks of coal. It is often referred to as 'hard coal'.

Field identification & locations

Identified by its shiny, almost metallic black surface and clean-to-the-touch handling compared to bitumen. Found in the Appalachian Mountains (Pennsylvania, US), China, and Russia. Collectors value specimens with high luster or 'rainbow' inclusions.