metamorphic
Anthracite Coal
Anthracite
Hardness: 2.5-3.0 (Mohs); Color: Black to steel gray; Luster: Sub-metallic to brilliant/greasy; Crystal Structure: Amorphous; Cleavage: Conchoidal fracture; Specific Gravity: 1.3-1.7.
- Hardness
- 2
- Color
- Black to steel gray
- Luster
- Sub-metallic to brilliant/greasy
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 2.5-3.0 (Mohs); Color: Black to steel gray; Luster: Sub-metallic to brilliant/greasy; Crystal Structure: Amorphous; Cleavage: Conchoidal fracture; Specific Gravity: 1.3-1.7.
Formation & geological history
Formed through the low-grade metamorphism of bituminous coal. It undergoes intense heat and pressure over millions of years, typically during mountain-building events (orogeny), resulting in the highest carbon content of all coals (86% to 98%).
Uses & applications
Historically used as a high-grade fuel for domestic heating and industrial steam production. Today, it is used in water filtration, as a reducing agent in metallurgy, and occasionally for carving into jewelry or artistic figurines.
Geological facts
Anthracite burns with a short, blue, smokeless flame. It is known as the cleanest-burning coal available because of its high carbon and low sulfur content. Large deposits are found in the Appalachian Mountains of Pennsylvania.
Field identification & locations
Identify by its hardness (doesn't soil fingers easily), brilliant high luster, and conchoidal fracture (curved breakages). It is primarily found in folded mountain belts. Collectors look for pieces with 'peacock' iridescence or unique shapes.
More like this
