sedimentary
Anthracite Coal
Anthracite (Highly Metamorphosed Coal)
Hardness: 2.5-3.0; Color: Jet black to brownish-black; Luster: Submetallic, vitreous (glassy); Structure: Amorphous/microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 1.3-1.8.
- Hardness
- 2
- Color
- Jet black to brownish-black
- Luster
- Submetallic, vitreous (glassy)
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Physical properties
Hardness: 2.5-3.0; Color: Jet black to brownish-black; Luster: Submetallic, vitreous (glassy); Structure: Amorphous/microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 1.3-1.8.
Formation & geological history
Formed through the burial and intense subterranean heating of plant matter (peat) over millions of years. It represents the highest rank of coal, having undergone low-grade metamorphism that removes most moisture and volatiles.
Uses & applications
Primarily used for domestic heating and industrial processes requiring high carbon content. It is also used in water filtration systems and occasionally carved into jewelry or decorative ornaments.
Geological facts
Anthracite contains the highest carbon count (86-98%) and the fewest impurities of all coal types. It burns with a short blue flame and produces very little smoke or soot compared to bituminous coal.
Field identification & locations
Identify by its glassy luster, light weight (low density), and the fact that it does not soil fingers as much as softer coals. Commonly found in Pennsylvania (USA), Wales, and China. Collectors look for pieces with iridescent 'peacock' tarnish.
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