Anthracite Coal

Hardness: 2.5–3.0 (Mohs scale); Color: Black to steel-gray; Luster: Sub-metallic to vitreous (glassy); Crystal structure: Amorphous; Cleavage: None (conchoidal fracture); Specific gravity: 1.3–1.8

Formed through the low-grade metamorphism of bituminous coal. It is the highest rank of coal, created under extreme heat and pressure over millions of years, typically in areas of intense mountain building (orogeny) like the Appalachian Mountains. Most deposits date to the Carboniferous period (300-360 million years ago).

Primarily used for domestic heating and industrial processes requiring high temperatures and low smoke. In the 19th and early 20th centuries, it was the preferred fuel for steam locomotives and smelting. Today, it is also used for water filtration and as a specialty fuel for blacksmithing.

Anthracite is known as 'hard coal' and is the cleanest burning of all coal types. Because of its high carbon density and low moisture, it burns with a blue, smokeless flame. It accounts for only about 1% of the world's coal reserves.

Identify in the field by its high luster, smooth texture, and tendency to break into curved (conchoidal) shards rather than blocky pieces. It does not stain fingers as easily as softer coal. Major deposits are found in Northeastern Pennsylvania (USA), Wales, China, and Russia.