metamorphic
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
Hardness: 2.5–3.0 on Mohs scale; Color: Black to steel grey; Luster: Sub-metallic to vitreous (glassy); Crystal Structure: Amorphous; Cleavage: Conchoidal fracture; Specific Gravity: 1.3–1.8.
- Hardness
- 2
- Color
- Black to steel grey
- Luster
- Sub-metallic to vitreous (glassy)
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 grey; Luster: Sub-metallic to vitreous (glassy); Crystal Structure: Amorphous; Cleavage: Conchoidal fracture; Specific Gravity: 1.3–1.8.
Formation & geological history
Formed through the prograde metamorphism of bituminous coal under intense heat and pressure over millions of years, typically during mountain-building events (orogenies). Most commercial anthracite dates back to the Carboniferous period (approx. 300 million years ago).
Uses & applications
Historically used as a high-quality domestic fuel due to its smokeless burn. Currently used in industrial metallurgy, water filtration systems, and as a material for decorative carvings or jewelry specimens.
Geological facts
Anthracite contains the highest carbon count (86%–97%) and the fewest impurities of all coal types. It is often referred to as 'hard coal' and burns with a short, blue, smokeless flame.
Field identification & locations
Identify in the field by its distinct metallic sheen, lack of soot when handled compared to bituminous coal, and its ability to scratch glass with difficulty. Frequently found in the Appalachian region of Pennsylvania, UK, and China.
More like this
