sedimentary

Anthracite Coal

Anthracite coal (High-rank coal)

Hardness: 2.5-3 (Mohs scale); Color: Black or deep iron-black; Luster: Submetallic, vitreous (glassy); Crystal Structure: Amorphous (non-crystalline carbon); Cleavage: Conchoidal fracture; Specific Gravity: 1.3-1.7.

Hardness: 2
Color: Black or deep iron-black
Luster: Submetallic, vitreous (glassy)

Identified June 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the metamorphism of peat or bituminous coal under high pressure and temperature in mountain-building environments (orogeny). Most deposits date back to the Carboniferous period, approximately 300 to 360 million years ago.

Uses & applications

Primarily used as a high-grade fuel for domestic heating and industrial processes (smelting). It is also used in water filtration systems and occasionally carved for decorative ornaments.

Geological facts

Anthracite is the highest rank of coal, containing 86% to 98% carbon. Unlike softer coals, it burns with a blue flame and creates very little smoke or soot. It is often referred to as 'hard coal' or 'black diamond.'

Field identification & locations

Identify in the field by its high luster, glassy texture, and the fact that it does not soil fingers like graphite or bituminous coal. Commonly found in folded mountain belts like the Appalachian Mountains in Pennsylvania, USA.

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