sedimentary
Anthracite
Anthracite Coal
Hardness: 2.5-3 (Mohs scale), Color: Jet black to dark gray, Luster: Sub-metallic to vitreous (glassy), Structure: Amorphous (non-crystalline), Cleavage: Conchoidal fracture, Specific Gravity: 1.3-1.8
- Hardness
- 2
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Physical properties
Hardness: 2.5-3 (Mohs scale), Color: Jet black to dark gray, Luster: Sub-metallic to vitreous (glassy), Structure: Amorphous (non-crystalline), Cleavage: Conchoidal fracture, Specific Gravity: 1.3-1.8
Formation & geological history
Formed through the regional metamorphism of bituminous coal in sedimentary basins; it is the highest grade of coal and has been subject to the greatest pressure and heat. Dates primarily from the Carboniferous Period (300-360 million years ago).
Uses & applications
Primarily used for high-grade industrial heating, residential heating in some regions, and as a filtration medium in water treatment. It is also carved for ornamental items or jewelry (jet-like).
Geological facts
Anthracite contains the highest carbon content (86%-98%) and the fewest impurities of all coal types. It burns with a short, blue, smokeless flame. It is often referred to as 'hard coal'.
Field identification & locations
Identify by its high luster, cleanliness to the touch compared to other coals, and its characteristic conchoidal fracture. It is much denser and harder than bituminous coal and will not easily soil the hands. Mostly found in the Appalachian region of Pennsylvania, USA.
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