metamorphic
Anthracite Coal
Anthracite
Hardness: 2.5-3.0 (Mohs); Color: Black to metallic steel gray; Luster: Sub-metallic to vitreous; Structure: Amorphous (non-crystalline); Conchoidal fracture; Specific gravity: 1.3-1.8
- Hardness
- 2
- Color
- Black to metallic steel gray
- Luster
- Sub-metallic to vitreous
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Physical properties
Hardness: 2.5-3.0 (Mohs); Color: Black to metallic steel gray; Luster: Sub-metallic to vitreous; Structure: Amorphous (non-crystalline); Conchoidal fracture; Specific gravity: 1.3-1.8
Formation & geological history
Formed through the regional metamorphism of bituminous coal under intense pressure and heat. Often originated in the Carboniferous period (300-360 million years ago) from compressed peat in tropical swamp environments.
Uses & applications
Used primarily as a high-grade fuel for domestic heating and industrial power generation due to its high carbon content and low impurities; also used in water filtration systems and as a pigment (carbon black).
Geological facts
Anthracite is the highest rank of coal, containing 86% to 98% carbon. It burns with a short, blue, smokeless flame and is the cleanest burning form of coal.
Field identification & locations
Identify by its high luster (shininess), black streak, and the fact that it does not soil fingers as easily as softer coals. Common locations include the Appalachian Mountains of Pennsylvania, USA, and parts of Wales, UK.
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