metamorphic
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Hardness: 2.5–3.0 on Mohs scale; Color: Black or deep steel gray; Luster: Sub-metallic to vitreous (glassy); Structure: Amorphous/non-crystalline; Cleavage: Conchoidal fracture; Specific Gravity: 1.3–1.8
- Hardness
- 2
- Color
- Black or deep steel gray
- Luster
- Sub-metallic to vitreous (glassy)
Identified More metamorphic →
Explore Anthracite Coal in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 2.5–3.0 on Mohs scale; Color: Black or deep steel 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 regional metamorphism of sedimentary coal (bituminous coal) under intense heat and pressure, typically during mountain-building events. Most deposits date back to the Carboniferous period, approximately 300 to 360 million years ago.
Uses & applications
Primarily used as a high-grade fuel for domestic heating and industrial processes due to its high carbon content and low impurity levels. Also used for water filtration and as a pigment or decorative material in carvings.
Geological facts
Anthracite is the highest rank of coal, containing between 86% and 97% carbon. It burns with a short, blue, smokeless flame and is often referred to as 'hard coal' or 'black diamond.'
Field identification & locations
Identified by its shiny, almost metallic lustre and its clean touch (it does not soil fingers as much as soft coal). Common locations include the Appalachian Mountains in Pennsylvania, USA, South Wales, and parts of China and Russia.
