metamorphic
Anthracite
Anthracite coal
Hardness: 2-2.5 (Mohs scale), Color: black to brownish-black, Luster: submetallic to vitreous, Structure: amorphous/compact, Cleavage: conchoidal fracture, Specific Gravity: 1.3-1.8
- Hardness
- 2-2
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Physical properties
Hardness: 2-2.5 (Mohs scale), Color: black to brownish-black, Luster: submetallic to vitreous, Structure: amorphous/compact, Cleavage: conchoidal fracture, Specific Gravity: 1.3-1.8
Formation & geological history
Formed through the low-grade metamorphism of bituminous coal. This process involves the application of heat and pressure over millions of years, typically occurring in mountain-building (orogenic) zones.
Uses & applications
Primarily used for heating, fuel in metallurgy, and as a filtration medium for water. High-quality specimens are also used in jewelry and decorative carvings (jet-like).
Geological facts
Anthracite has the highest carbon content (86% to 97%), the fewest impurities, and the highest energy density of all types of coal. It burns with a short blue flame and produces very little smoke.
Field identification & locations
Identify by its glassy luster, lack of soot when handled compared to other coals, and heavy weight relative to charcoal. Commonly found in folded mountain belts like the Appalachians in Pennsylvania.
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