sedimentary

Coal (likely Anthracite)

Anthracite coal

Hardness: 2.5-3.0 (Mohs); Color: Black or brownish-black; Luster: Submetallic to vitreous (glassy); Structure: Amorphous (non-crystalline); Cleavage: Conchoidal fracture; Specific gravity: 1.3-1.7

Hardness: 2
Color: Black or brownish-black
Luster: Submetallic to vitreous (glassy)

Identified April 4, 2026More sedimentary →

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Physical properties

Hardness: 2.5-3.0 (Mohs); Color: Black or brownish-black; Luster: Submetallic to vitreous (glassy); Structure: Amorphous (non-crystalline); Cleavage: Conchoidal fracture; Specific gravity: 1.3-1.7

Formation & geological history

Formed through the lithification of plant remains (peat) under high pressure and temperature over millions of years, primarily during the Carboniferous period (300-360 million years ago).

Uses & applications

Primarily used as a fuel source for electricity generation and heating, as well as in the production of steel, cement, and chemical products.

Geological facts

Anthracite is the highest grade of coal, containing the highest percentage of carbon and the fewest impurities of all coal types. It burns with a clean blue flame and high heat output.

Field identification & locations

Identify by its black color, relatively low density (lighter than most rocks), and way it smudges or breaks into shiny fragments. Commonly found near railroad tracks or historic mining districts.