sedimentary
Coal
Bituminous Coal / Anthracite
Hardness: 1-2.5 on the Mohs scale. Color: Black to dark brown. Luster: Dull to sub-vitreous or pitchy. Crystal structure: Amorphous (organic-derived sedimentary rock). Streak: Black or brownish-black. Specific gravity: 1.1-1.5.
- Hardness
- 1-2
- Color
- Black to dark brown
- Luster
- Dull to sub-vitreous or pitchy
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Physical properties
Hardness: 1-2.5 on the Mohs scale. Color: Black to dark brown. Luster: Dull to sub-vitreous or pitchy. Crystal structure: Amorphous (organic-derived sedimentary rock). Streak: Black or brownish-black. Specific gravity: 1.1-1.5.
Formation & geological history
Formed from the accumulation, burial, and compaction of plant debris (peat) in ancient wetland swamps, typically subjected to increasing heat and pressure over millions of years, commonly dating from the Carboniferous period.
Uses & applications
Historically used as a primary fossil fuel for electricity generation, heating, and industrial steel production.
Geological facts
Coal deposits store solar energy captured by plants hundreds of millions of years ago through photosynthesis.
Field identification & locations
Lightweight, dark, and burns when exposed to flame; commonly found in sedimentary basins and coal-bearing geological formations worldwide.
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