metamorphic
Anthracite Coal
Anthracite
Hardness: 2.5-3.0 Mohs; Color: Black to steel gray with a metallic luster; Luster: Sub-metallic to vitreous; Crystal Structure: Amorphous (non-crystalline); Conchoidal fracture; Specific gravity: 1.3-1.8.
- Hardness
- 2
- Color
- Black to steel gray with a metallic luster
- Luster
- Sub-metallic to vitreous
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Physical properties
Hardness: 2.5-3.0 Mohs; Color: Black to steel gray with a metallic luster; Luster: Sub-metallic to vitreous; Crystal Structure: Amorphous (non-crystalline); Conchoidal fracture; Specific gravity: 1.3-1.8.
Formation & geological history
Formed through the regional metamorphism of bituminous coal. It involves the application of high heat and pressure over millions of years, typically during mountain-building events (orogenies). Most deposits were formed during the Carboniferous period.
Uses & applications
Primary use is as a high-grade fuel for domestic and industrial heating because it burns with a clean flame and high heat output. It is also used in water filtration systems and as a source for carbon in steel production.
Geological facts
Anthracite is the highest rank of coal, containing between 86% to 98% carbon. Unlike other coals, it is relatively clean to touch and does not leave black soot on hands as easily as softer coal varieties.
Field identification & locations
Identify by its high luster, hardness (it will not easily crumble like bituminous coal), and lack of visible plant fossils. Commonly found in folded mountain belts like the Appalachian Mountains in Pennsylvania, USA.
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