sedimentary
Anthracite Coal
Anthracite
Hardness: 2.5-3.0; Color: Black to dark grey; Luster: Submetallic, vitreous (glassy); Structure: Amorphous; Fracture: Conchoidal; Specific Gravity: 1.3-1.8.
- Hardness
- 2
- Color
- Black to dark grey
- Luster
- Submetallic, vitreous (glassy)
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Physical properties
Hardness: 2.5-3.0; Color: Black to dark grey; Luster: Submetallic, vitreous (glassy); Structure: Amorphous; Fracture: Conchoidal; Specific Gravity: 1.3-1.8.
Formation & geological history
Formed through the metamorphism of peat or bituminous coal under high pressure and temperature over millions of years, typically in folded mountain belts. It has the highest carbon content of all coals (86-97%).
Uses & applications
Primarily used as a residential and commercial heating fuel because it burns cleanly with little smoke. Also used in water filtration, steel making, and as a collector's specimen.
Geological facts
It is often called 'hard coal' and is the most metamorphosed type of coal. Unlike other forms of coal, it doesn't leave soot on fingers when touched and burns much slower and hotter.
Field identification & locations
Identify by its shiny, almost metallic black surface and its tendency to break with smooth, curved surfaces (conchoidal fracture). Commonly found in Pennsylvania, USA, and parts of South Wales and China.
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