metamorphic
Anthracite Coal
Anthracite
Hardness: 2.5-3.0 (Mohs scale); Color: Black to steel gray; Luster: Sub-metallic, vitreous; Crystal structure: Amorphous; Cleavage: None (conchoidal fracture); Specific gravity: 1.3-1.8
- Hardness
- 2
- Color
- Black to steel gray
- Luster
- Sub-metallic, vitreous
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Physical properties
Hardness: 2.5-3.0 (Mohs scale); Color: Black to steel gray; Luster: Sub-metallic, vitreous; Crystal structure: Amorphous; Cleavage: None (conchoidal fracture); Specific gravity: 1.3-1.8
Formation & geological history
Formed through the regional metamorphism of bituminous coal in sedimentary basins. This process occurs under high pressure and temperature over millions of years, often during mountain-building events (orogenies).
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 items.
Geological facts
Anthracite is the highest rank of coal, containing between 86% and 97% carbon. It burns with a short blue flame and produces very little smoke or soot compared to other coal types.
Field identification & locations
Identify by its high luster (very shiny), hardness compared to other coals, and lack of sooty residue when touched. Common locations include the Appalachian Mountains of Pennsylvania, USA, and parts of South Wales and China.
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