sedimentary
Coal
Carbonaceous sedimentary rock / Lignite to Bituminous coal
Hardness: 1-3 on the Mohs scale; Color: Dark brown to black; Luster: Dull to sub-vitreous; Structure: Amorphous, layered; Specific Gravity: 1.1-1.5
- Hardness
- 1-3 on the Mohs scale
- Color
- Dark brown to black
- Luster
- Dull to sub-vitreous
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Physical properties
Hardness: 1-3 on the Mohs scale; Color: Dark brown to black; Luster: Dull to sub-vitreous; Structure: Amorphous, layered; Specific Gravity: 1.1-1.5
Formation & geological history
Formed from the accumulation, burial, and compaction of plant debris in ancient swamps and wetlands over millions of years (Carboniferous period and later).
Uses & applications
Primary used for electricity generation, steel production, and industrial heating.
Geological facts
Coal is often called 'buried sunshine' because it stores solar energy captured by ancient plants hundreds of millions of years ago.
Field identification & locations
Found extensively in sedimentary basins worldwide, particularly in regions with ancient swamp deposits. It is easily identified by its light weight, dark color, and black streak.
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