sedimentary
Coal (Anthracite or Bituminous)
Carbon (C) with varying hydrocarbon and mineral impurities
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
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Physical properties
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
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.
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