sedimentary

Anthracite Coal

Anthracite

Hardness: 2.5–3.0 on Mohs scale; Color: Black to dark steel-gray; Luster: Metallic to sub-metallic; Structure: Amorphous (non-crystalline); Conchoidal fracture; Specific Gravity: 1.3–1.8

Hardness: 2
Color: Black to dark steel-gray
Luster: Metallic to sub-metallic

Identified July 7, 2026More sedimentary →

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Physical properties

Hardness: 2.5–3.0 on Mohs scale; Color: Black to dark steel-gray; Luster: Metallic to sub-metallic; Structure: Amorphous (non-crystalline); Conchoidal fracture; Specific Gravity: 1.3–1.8

Formation & geological history

Formed through the lowest grade of metamorphism of bituminous coal. It originated from accumulation of plant debris in swampy environments during the Carboniferous period (approx. 300-360 million years ago) and was subjected to high heat and pressure.

Uses & applications

Primarily used as a high-grade fuel for domestic and industrial heating because it burns with little smoke or flame. It is also used in water filtration systems and as a source of carbon for various industrial processes.

Geological facts

Anthracite is the highest rank of coal, containing the highest percentage of fixed carbon (86% to 98%) and the lowest amount of volatile matter. It is often referred to as 'hard coal' to distinguish it from softer bituminous coal.

Field identification & locations

Can be identified by its shiny, almost metallic luster and its tendency to not soil fingers when handled, unlike lower ranks of coal. It is commonly found in mountainous regions such as the Appalachian Mountains in Pennsylvania, USA, where tectonic activity provided the necessary pressure for its formation.