metamorphic
Anthracite Coal
Anthracite (Carbon-based organic sedimentary/metamorphic rock)
Hardness: 2.5–3.0 on Mohs scale; Color: Black to steel gray with a sub-metallic luster; Crystal structure: Amorphous (non-crystalline); Fracture: Conchoidal; Specific Gravity: 1.3–1.8
- Hardness
- 2
- Color
- Black to steel gray with a sub-metallic luster
Identified More metamorphic →
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 to steel gray with a sub-metallic luster; Crystal structure: Amorphous (non-crystalline); Fracture: Conchoidal; Specific Gravity: 1.3–1.8
Formation & geological history
Formed through the burial and intense subterranean heating/pressure of peat and bituminous coal over millions of years (often Carboniferous period). It is considered the highest rank of coal due to its high carbon content and low volatile matter.
Uses & applications
Used primarily for residential and industrial heating, charcoal production, and high-purity water filtration. In the 19th century, it was the primary fuel for steam power and early steel production.
Geological facts
Anthracite contains the highest percentage of carbon (86%-98%) and the lowest amount of impurities among all types of coal. Unlike lower-grade coal, it burns with a clean blue flame and produces very little smoke or soot.
Field identification & locations
Identify by its glossy, glass-like luster (sub-metallic), light weight compared to stone, and tendency to break along smooth curved surfaces (conchoidal fracture). It will not leave a heavy soot residue on hands like bitumous coal.
More like this
