metamorphic
Anthracite Coal
Anthracite
Hardness: 2.5–3 on Mohs scale; Color: Black to steel-gray; Luster: Sub-metallic to vitreous; Crystal Structure: Amorphous; Cleavage: Conchoidal fracture; Specific Gravity: 1.3–1.8
- Hardness
- 2
- Color
- Black to steel-gray
- Luster
- Sub-metallic to vitreous
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Physical properties
Hardness: 2.5–3 on Mohs scale; Color: Black to steel-gray; Luster: Sub-metallic to vitreous; Crystal Structure: Amorphous; Cleavage: Conchoidal fracture; Specific Gravity: 1.3–1.8
Formation & geological history
Formed through the low-grade metamorphism of bituminous coal. It undergoes intense pressure and heat over millions of years, typically in fold mountain belts like the Appalachians. It has the highest carbon count (86-97%) of all coal types.
Uses & applications
Used primarily as a high-grade fuel for domestic heating and industrial processes due to its high energy density and low smoke production. Also used in water filtration and as a reduction agent in metallurgy.
Geological facts
Anthracite is the most 'metamorphosed' type of coal. It burns with a short, blue, and smokeless flame. It is sometimes referred to as 'hard coal' or 'black diamond.'
Field identification & locations
Identify in the field by its high luster (very shiny), hardness compared to other coals, and its tendency not to soil the fingers when handled. Commonly found in Pennsylvania (USA), Wales, and China.
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