metamorphic
Anthracite Coal
Anthracite
Hardness: 2.5-3.0; Color: Black to steel gray; Luster: Submetallic, vitreous; Crystal Structure: Amorphous (non-crystalline); Conchoidal fracture; Specific Gravity: 1.3-1.7.
- Hardness
- 2
- Color
- Black to steel gray
- Luster
- Submetallic, vitreous
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Physical properties
Hardness: 2.5-3.0; Color: Black to steel gray; Luster: Submetallic, vitreous; Crystal Structure: Amorphous (non-crystalline); Conchoidal fracture; Specific Gravity: 1.3-1.7.
Formation & geological history
Formed through the low-grade metamorphism of bituminous coal. It typically originates from plant matter buried in Carboniferous or Cretaceous swamps that underwent extreme pressure and heat over millions of years.
Uses & applications
Primarily used as a high-grade fuel for residential and industrial heating, and in the production of carbon filters and water purification systems due to its high carbon content.
Geological facts
Anthracite contains the highest carbon count (86-97%) and the fewest impurities of all coal types. It burns with a short blue flame and emits very little smoke compared to bituminous coal.
Field identification & locations
Identify in the field by its high luster, lack of soot when handled compared to other coals, and its tendency to break into curved (conchoidal) shards. It is found in mountainous regions like the Appalachians in Pennsylvania.
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