metamorphic
Anthracite Coal
Anthracite (Carbon-based metamorphic rock)
Hardness: 2.5-3 (Mohs scale), Color: Jet black to iron-black, Luster: Sub-metallic to vitreous, 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 iron-black, Luster: Sub-metallic to vitreous, 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 rank of coal, having been subjected to the most heat and pressure, often dating to the Carboniferous period (300-360 million years ago).
Uses & applications
Primarily used for high-efficiency heating in residential and industrial settings, water filtration media, and as a reducing agent in metallurgy.
Geological facts
Anthracite contains the highest carbon content of all coals (86%-97%) and burns with a short, blue, smokeless flame. It is much cleaner and harder than standard soft coal.
Field identification & locations
Identify in the field by its high luster (shininess), lack of soot when handled compared to other coals, and its characteristic conchoidal (shell-like) fracture patterns. Frequently found in the Appalachian mountains of Pennsylvania.
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