sedimentary
Anthracite Coal
Anthracite (Metamorphosed Bituminous Coal)
Hardness: 2.5-3.0 Mohs scale; Color: Black to dark grey; Luster: Sub-metallic to vitreous; Structure: Amorphous/Massive; Cleavage: Conchoidal fracture; Specific gravity: 1.3-1.8.
- Hardness
- 2
- Color
- Black to dark grey
- Luster
- Sub-metallic to vitreous
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Physical properties
Hardness: 2.5-3.0 Mohs scale; Color: Black to dark grey; Luster: Sub-metallic to vitreous; Structure: Amorphous/Massive; Cleavage: Conchoidal fracture; Specific gravity: 1.3-1.8.
Formation & geological history
Formed through the regional metamorphism of bituminous coal. It originated 250-350 million years ago during the Carboniferous period from decayed plant matter subjected to extreme heat and pressure in oxygen-poor environments.
Uses & applications
Primarily used for high-efficiency heating and power generation due to its high carbon content. Finely carved coal (like the figurine shown) is popular in the souvenirs and folk art industry, particularly in mining regions.
Geological facts
Anthracite is the highest rank of coal, containing 86% to 97% carbon. Unlike other coals, it burns with a short blue flame and produces very little smoke or odors. It is sometimes referred to as 'hard coal' or 'black diamond'.
Field identification & locations
Identify by its high luster, lightweight feel relative to size, and the fact that it does not soil fingers as much as softer coals. Common locations include the Appalachian Mountains of Pennsylvania, USA, and South Wales, UK.
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