Anthracite

Physical Properties

Hardness: 2.5–3.0 on Mohs scale; Color: Black to steel gray; Luster: Submetallic, vitreous; Crystal Structure: Amorphous (non-crystalline); Cleavage: Conchoidal fracture; Specific Gravity: 1.3–1.8.

Formation & Geological History

Formed through the regional metamorphism of bituminous coal in sedimentary basins. It is the highest grade of coal, subjected to intense heat and pressure over millions of years, typically dating from the Carboniferous period.

Uses & Applications

Primarily used as a high-grade fuel for residential and industrial heating due to its high carbon content and low impurity levels. Also used for water filtration and as a reduction agent in metal smelting.

Geological Facts

Anthracite contains the highest percentage of fixed carbon (86% to 98%) of all coal types. It burns with a short, blue, smokeless flame. It is often referred to as 'hard coal'.

Field Identification & Locations

Identified in the field by its high luster, hardness compared to other coals, and lack of soot when handled. It is commonly found in folded mountain belts like the Ridge-and-Valley Appalachians in Pennsylvania, USA.

Identified on: 5/16/2026

Mode: Standard