metamorphic
Anthracite Coal
Anthracite C
Hardness: 2.5-3.0 (Mohs). Color: Black to deep iron-black. Luster: Submetallic to metallic, vitreous. Crystal structure: Amorphous/non-crystalline. Cleavage: Conchoidal fracture. Specific gravity: 1.3-1.8.
- Hardness
- 2
- Color
- Black to deep iron-black
- Luster
- Submetallic to metallic, vitreous
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Physical properties
Hardness: 2.5-3.0 (Mohs). Color: Black to deep iron-black. Luster: Submetallic to metallic, vitreous. Crystal structure: Amorphous/non-crystalline. Cleavage: Conchoidal fracture. Specific gravity: 1.3-1.8.
Formation & geological history
Formed through the high-grade metamorphism of bituminous coal under intense pressure and heat within the earth's crust, typically during mountain-building events (orogeny). Most deposits are 250-350 million years old (Carboniferous period).
Uses & applications
Primarily used as a high-grade fuel for domestic heating and industrial power generation. It is also used in water filtration systems and as a reducing agent in metallurgical processes.
Geological facts
Anthracite is the highest rank of coal, containing the highest percentage of fixed carbon (up to 98%) and the lowest amount of impurities or volatile matter. It burns with a clean, blue flame and very little smoke.
Field identification & locations
Identify by its clean-to-the-touch nature (unlike sootier coals), metallic luster, and hardness. It is commonly found in folded mountain belts like the Appalachian Mountains in Pennsylvania, USA, and parts of South Wales and China.
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