sedimentary

Coal (Anthracite or Bituminous)

Carbon (C) with varying hydrocarbon and mineral impurities

AI-generated identification · may be incorrect

Hardness: 1-2.5 (Mohs), Color: brownish-black to black, Luster: dull to sub-metallic, Crystal structure: amorphous (none), Cleavage: non-existent but may have conchoidal fracture, Specific gravity: 1.1–1.5

Hardness: 1-2

Identified June 27, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed via the accumulation of plant matter in swampy environments (peat), which is then buried and subjected to heat and pressure over millions of years (coalification). Most major deposits date back to the Carboniferous period.

Uses & applications

Primarily used as a fossil fuel for electricity generation and industrial heating; also used in the production of coke for steel manufacturing and as a source for chemicals like ammonia.

Geological facts

Coal is the most abundant fossil fuel on Earth; anthracite is the highest grade of coal and has the highest carbon content, making it burn the cleanest.

Field identification & locations

Identified in the field by its low density (feels light for its size), black streak, and tendency to be found in bedded layers or seams. It is brittle and often soils the hands with black dust.