metamorphic
Anthracite Coal
Anthracite (Carbon)
Hardness: 2.5-3 (Mohs scale), Color: Black to deep iron-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: Black to deep iron-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 low-grade metamorphism of bituminous coal. Significant heat and pressure over millions of years (often Carboniferous period) drive off volatiles and water, resulting in the highest carbon content of all coal types.
Uses & applications
Primarily used as a residential and industrial fuel due to its high energy density and clean-burning properties. Also used for water filtration and as a pigment or decorative carving material.
Geological facts
Anthracite contains the highest carbon count (86%-97%) and the fewest impurities of all coal types. It is often referred to as 'stone coal' or 'hard coal' because it does not soil fingers when touched, unlike lower grades of coal.
Field identification & locations
Identify in the field by its high luster, lack of soot when handled, and tendency to break in curved (conchoidal) patterns. Commonly found in Pennsylvania (USA), Wales, China, and Russia.
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