metamorphic
Anthracite Coal
Anthracite (Hard Coal)
Hardness: 2.5-3.0; Color: Jet black; Luster: Sub-metallic to vitreous; Structure: Amorphous/Compact; Cleavage: Conchoidal fracture; Specific Gravity: 1.3-1.8
- Hardness
- 2
- Color
- Jet black
- Luster
- Sub-metallic to vitreous
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Physical properties
Hardness: 2.5-3.0; Color: Jet black; Luster: Sub-metallic to vitreous; Structure: Amorphous/Compact; Cleavage: Conchoidal fracture; Specific Gravity: 1.3-1.8
Formation & geological history
Formed through the low-grade metamorphism of bituminous coal under high pressure and temperature. Primarily formed during the Carboniferous period (300-360 million years ago) in swampy environments.
Uses & applications
Used historically for domestic heating and industrial fuel; in modern times, it is used for charcoal filters, water purification, and as a component in steel making.
Geological facts
Anthracite is the highest rank of coal, containing the highest carbon content (86-97%) and the fewest impurities. It burns with a short blue flame and produces very little smoke.
Field identification & locations
Identified by its shiny, glass-like appearance and tendency not to soil fingers like softer coals. Found in folded mountain belts like the Appalachians in Pennsylvania, USA.
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