Anthracite Identification Guide

What Anthracite Looks Like

Anthracite is the highest rank of coal, a hard, dense, low-volatile fossil fuel formed from peat that was deeply buried and metamorphosed. It is iron-black to brownish-black with a distinctive bright, almost metallic to submetallic or glassy (vitreous) luster, much shinier than softer coals. Fresh broken surfaces are clean and lustrous rather than dull and sooty.

• Color: black to grayish-black
• Luster: bright submetallic to vitreous (the "glance coal" sheen)
• Transparency: opaque
• Form: massive, no crystal form; often blocky with sharp conchoidal fracture
• Feel: hard, clean, and relatively non-marking compared with bituminous coal

Step-by-Step Field ID Checklist

1. Check the shine: anthracite has a bright, almost metallic luster; dull, banded, or sooty black material is more likely lower-rank coal.
2. Test how it marks your hands: anthracite barely soils your fingers, while bituminous and lignite leave black smudges.
3. Break a corner: look for smooth, curved conchoidal fracture surfaces.
4. Scratch test: anthracite is harder than other coals but still soft against minerals.
5. Heft it: denser and harder than other coals; it feels solid rather than crumbly.

Key Diagnostic Tests

• Mohs hardness: about 2.5 to 3, hard for a coal but still scratched by a knife
• Streak: black, but lighter and less sooty than softer coals
• Fracture: conchoidal, sub-conchoidal
• Specific gravity: about 1.3 to 1.4, light but denser than other coals
• Combustion: burns with a short, nearly smokeless blue flame and high heat; hard to ignite
• Carbon content: very high fixed carbon (roughly 86 to 97 percent), very low volatiles
• Acid/magnetism: no acid reaction; not magnetic

Common Look-Alikes and How to Tell Them Apart

• Bituminous coal: duller, often banded with shiny and dull layers, marks the hands readily, and burns smokier; lower fixed carbon than anthracite.
• Lignite: brown-black, dull, soft, and often shows woody texture; far lower rank.
• Jet: also black and lustrous but tougher, takes a high polish, is lighter, and is used as a gem; jet is fossilized wood (a form of lignite), warmer to the touch and not as brittle/glassy.
• Obsidian: glassy black volcanic glass, but obsidian is much harder (5 to 5.5), scratches glass, and has sharp conchoidal edges; anthracite is soft and burns.
• Hematite/magnetite (black ores): far denser and harder, with red (hematite) or black streak and magnetism (magnetite); anthracite is light and combustible.

Where Anthracite Is Typically Found

Anthracite forms where coal-bearing strata were strongly folded and heated, especially near mountain belts. The classic district is northeastern Pennsylvania (the Anthracite Region around Scranton and Wilkes-Barre). Other deposits occur in South Wales (UK), the Donbas (Ukraine), Vietnam, China, and parts of the eastern Appalachians.