metamorphic
Anthracite
Anthracite coal
Hardness: 2.5-3.0 Mohs; Color: Black or brownish-black; Luster: Submetallic, shiny; Crystal structure: Amorphous; Fracture: Conchoidal; Density: 1.3-1.8 g/cm3
- Hardness
- 2
- Color
- Black or brownish-black
- Luster
- Submetallic, shiny
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Physical properties
Hardness: 2.5-3.0 Mohs; Color: Black or brownish-black; Luster: Submetallic, shiny; Crystal structure: Amorphous; Fracture: Conchoidal; Density: 1.3-1.8 g/cm3
Formation & geological history
Formed through high-grade metamorphism of peat and lower-grade coal in sedimentary basins under intense pressure and heat, typically associated with mountain-building events like the Alleghenian orogeny (approx 300 million years ago).
Uses & applications
Used primarily as a high-quality fuel for domestic and industrial heating, in the production of specialty carbons and water filtration media, and historically for steam generation.
Geological facts
Anthracite has the highest carbon count (86-97%) and the fewest impurities of any coal. It was once widely used to heat homes because it burns with a blue flame and produces very little smoke.
Field identification & locations
Identified in the field by its high luster, hardness compared to bituminious coal, and conchoidal (glass-like) fracture. Found in highly deformed mountain belts like the Appalachian Mountains in Pennsylvania, USA.
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