sedimentary

Bituminous Coal

Coal (Sedimentary Rock)

Hardness on Mohs scale is 1.5 to 2.5; color is black to dark brown; luster ranges from dull to sub-vitreous or greasy; amorphous crystal structure; specific gravity is 1.1 to 1.5.

Identified August 3, 2026More sedimentary →

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Physical properties

Hardness on Mohs scale is 1.5 to 2.5; color is black to dark brown; luster ranges from dull to sub-vitreous or greasy; amorphous crystal structure; specific gravity is 1.1 to 1.5.

Formation & geological history

Formed from the accumulation and compaction of plant debris (peat) in ancient swamp environments over millions of years (primarily Carboniferous and Permian periods), subjected to increasing heat and pressure as sediments buried them.

Uses & applications

Primarily used for electricity generation, steel production, cement manufacturing, and formerly as a heating fuel.

Geological facts

Coal has been a vital energy source since the Industrial Revolution and contains the fossilized remains of ancient swamp forests that existed over 300 million years ago.

Field identification & locations

Easily identified by its dark black color, relatively low weight, black streak on porcelain, and tendency to soil the fingers when handled. Found globally in sedimentary basins.