sedimentary
Bituminous Coal
Humic coal (Carboniferous fossil fuel)
Hardness: 0.5-2.5 on Mohs scale; Color: Black to dark brown; Luster: Dull to sub-vitreous; Crystal Structure: Amorphous (non-crystalline); Cleavage: Cubic or blocky fracture; Specific Gravity: 1.1-1.4
- Hardness
- 0
- Color
- Black to dark brown
- Luster
- Dull to sub-vitreous
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Physical properties
Hardness: 0.5-2.5 on Mohs scale; Color: Black to dark brown; Luster: Dull to sub-vitreous; Crystal Structure: Amorphous (non-crystalline); Cleavage: Cubic or blocky fracture; Specific Gravity: 1.1-1.4
Formation & geological history
Formed from the burial and compression of plant matter in swampy environments. Most deposits date to the Carboniferous period (300-360 million years ago) through biochemical and geochemical changes (coalification).
Uses & applications
Primary fuel source for electricity generation and industrial steam; used to produce coke for steel manufacturing; historic use in residential heating.
Geological facts
Bituminous coal is the most abundant rank of coal. It is often referred to as 'soft coal' to distinguish it from the harder anthracite coal.
Field identification & locations
Identify by its black color, tendency to leave a black smudge on fingers, and blocky fracture patterns. Commonly found in massive sedimentary basins like the Appalachian Basin in the USA.
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