sedimentary
Anthracite Coal
Anthracite (Carbon-rich metamorphic sedimentary rock)
Hardness: 2.5-3.0 Mohs; Color: Jet black to dark grey; Luster: Sub-metallic to vitreous; Structure: Amorphous (non-crystalline); Specific Gravity: 1.3-1.8; Conchoidal fracture.
- Hardness
- 2
- Color
- Jet black to dark grey
- Luster
- Sub-metallic to vitreous
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Physical properties
Hardness: 2.5-3.0 Mohs; Color: Jet black to dark grey; Luster: Sub-metallic to vitreous; Structure: Amorphous (non-crystalline); Specific Gravity: 1.3-1.8; Conchoidal fracture.
Formation & geological history
Formed from the accumulation of plant matter in swamps during the Carboniferous period (300-360 million years ago), subjected to high heat and pressure during mountain building (orogeny).
Uses & applications
Primarily used as a high-grade fuel for domestic heating and industrial steam generation; also used in metallurgy and as a filtration medium for water purification.
Geological facts
Anthracite contains the highest carbon content of all coals (86% to 97%) and has the fewest impurities. It burns with a short blue flame and very little smoke.
Field identification & locations
Identify by its deep black color, shiny metallic-like surface, and the fact that it does not soil fingers when touched (unlike bituminous coal). Often found in folded mountain belts like the Appalachians.
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