sedimentary

Anthracite coal

Anthracite; predominantly carbon (C), with minor mineral ash

AI-generated identification · may be incorrect

Very dark gray to black, dense, brittle, and commonly has a bright submetalllic to vitreous luster; hardness about 2.5–3 Mohs, no consistent crystal structure, and irregular fracture. It may show conchoidal surfaces and faint banding.

Identified September 16, 2026More sedimentary →

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Physical properties

Formation & geological history

A high-rank coal formed when bituminous coal was subjected to intense heat and pressure during regional metamorphism, commonly during mountain building. Its age depends on the coal basin, often Paleozoic (roughly 250–350 million years old).

Uses & applications

Used as a smokeless fuel, in metallurgy, water filtration, and historically for heating; attractive lustrous pieces are collected but are not generally jewelry material.

Geological facts

Anthracite contains the highest fixed-carbon content of natural coals, typically about 86–97%, and burns with a short blue flame and little smoke.

Field identification & locations

Common in metamorphosed coal fields such as Pennsylvania’s Appalachian region, Wales, and parts of China and Russia. Identify it by its black color, exceptional hardness relative to softer coal, high density, and shiny fracture surfaces; avoid confusing it with graphite or bituminous coal.