sedimentary
Coal (Anthracite)
Anthracite Coal (C)
Hardness: 2.5-3.0 Mohs; Color: Iron-black to dark grey; Luster: Submetallic to vitreous; Crystal Structure: Amorphous; Cleavage: Conchoidal fracture; Specific Gravity: 1.3–1.7
- Hardness
- 2
- Color
- Iron-black to dark grey
- Luster
- Submetallic to vitreous
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Physical properties
Hardness: 2.5-3.0 Mohs; Color: Iron-black to dark grey; Luster: Submetallic to vitreous; Crystal Structure: Amorphous; Cleavage: Conchoidal fracture; Specific Gravity: 1.3–1.7
Formation & geological history
Formed through the metamorphism of peat and bituminous coal over millions of years under high pressure and temperature, often carboniferous in age (300-360 million years).
Uses & applications
Used primarily for heating, fuel for power generation, and carbon filtering. It was historically used in water filtration and as a pigment.
Geological facts
Anthracite is the highest rank of coal, containing 86%–97% carbon. Unlike other coals, it burns with a clean blue flame and produces very little smoke or soot.
Field identification & locations
Identify by its dark color, relative lightness (density), and lack of dirtiness compared to softer coals. Often found in folded mountain belts like the Appalachians.
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