metamorphic
Anthracite Coal with Sulfur staining
Anthracite (Carbon C with impurities)
Hardness: 2.5-3; Color: Black with metallic luster, yellow sulfur blooms; Crystal structure: Amorphous; Cleavage: Conchoidal fracture; Specific gravity: 1.3-1.7
- Hardness
- 2
- Color
- Black with metallic luster, yellow sulfur blooms
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Physical properties
Hardness: 2.5-3; Color: Black with metallic luster, yellow sulfur blooms; Crystal structure: Amorphous; Cleavage: Conchoidal fracture; Specific gravity: 1.3-1.7
Formation & geological history
Formed from the burial and heating of peat and lower-grade coal through intense pressure and heat (metamorphism), usually during mountain-building events.
Uses & applications
Primarily used for residential and industrial heating due to its high carbon content and low smoke; also found in filtration systems and as a medium for sculpture.
Geological facts
Anthracite is the highest grade of coal, containing 86%-98% carbon. The yellow staining seen here is often a byproduct of oxidizing iron pyrite into secondary sulfate minerals.
Field identification & locations
Identify by its bright metallic luster, lack of soot on hands compared to bituminous coal, and its relatively high density. Commonly found in Pennsylvania, USA and parts of China.
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