sedimentary
Anthracite Coal
Anthracite (Highly Metamorphosed Coal)
Hardness: 2.5-3.0; Color: Black or dark iron-black; Luster: Sub-metallic to vitreous (glassy); Crystal Structure: Amorphous; Fracture: Conchoidal; Specific Gravity: 1.3-1.7
- Hardness
- 2
- Color
- Black or dark iron-black
- Luster
- Sub-metallic to vitreous (glassy)
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Physical properties
Hardness: 2.5-3.0; Color: Black or dark iron-black; Luster: Sub-metallic to vitreous (glassy); Crystal Structure: Amorphous; Fracture: Conchoidal; Specific Gravity: 1.3-1.7
Formation & geological history
Formed through the burial and heating of plant matter (peat) over millions of years. Anthracite is the highest grade of coal, having undergone low-grade metamorphism that removes most volatile matter and moisture.
Uses & applications
Primarily used as a residential and industrial fuel due to its high energy density and low smoke production. Also used in water filtration systems and as a carbon source for steel production.
Geological facts
Anthracite has the highest carbon content of all coals (86% to 98%). It is the oldest and hardest coal, often referred to as 'hard coal' or 'black diamond'.
Field identification & locations
Identify in the field by its high luster, deep black color, and the fact that it does not soil fingers like softer coals. It is commonly found in the Appalachian region of Pennsylvania, USA, where it accounts for nearly all of the country's anthracite resources.
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