Anthracite
Anthracite is a hard, shiny, high-carbon coal. It often looks black, compact, lightweight for its size, and glassy to submetallic.
Anthracite properties at a glance
| Type | Metamorphic Rocks |
|---|---|
| Chemical formula | Carbon-rich metamorphic coal |
| Mohs hardness | 2.5 |
| Luster | submetallic |
| Streak | Black to dark gray |
| Cleavage | None |
| Fracture | Conchoidal to uneven |
| Specific gravity | 1.5 |
| Transparency | opaque |
| Common colors | Black, Steel gray |
| Rarity | common |
Geology & background
Forms when bituminous coal is metamorphosed by heat and pressure, increasing carbon content and luster.
Anthracite was an important domestic and industrial fuel in many mining regions and is useful for recognizing high-grade coal metamorphism.
How to identify Anthracite
- Look for black color, high shine, and a compact coal-like texture.
- Anthracite is usually lighter than metallic minerals of similar size.
- Curved, glassy-looking fracture surfaces can help separate it from matte shale.
- Do not confuse anthracite with jet, obsidian, hematite, or black slag without checking weight, streak, and texture.
Where Anthracite is found
Reported from multiple metamorphic terrains worldwide; verify locality against specimen provenance when available.
How much is Anthracite worth?
| Entry-level specimen | $1 |
|---|---|
| Typical collector specimen | $8 |
| Premium specimen | $50+ |
Anthracite is usually valued for teaching, field context, locality, texture, mineral content, or unusually attractive specimens rather than high gem value.
Common uses
- Field identification
- Education
- Fuel history specimens
- Carbon-rich rock comparison
Interesting facts
- Anthracite is the highest rank of coal.
- It commonly shows a bright black to steel-gray shine.
- Fresh broken surfaces can show curved or conchoidal fracture.
Care & safety
Anthracite can vary in toughness, cleavage, and weathering depending on mineral mix and fabric.
Avoid inhaling dust. Do not cut, grind, or polish unknown metamorphic rocks without eye protection and a properly rated respirator.
Keep away from flames. Anthracite is carbon-rich coal and can burn under the right conditions.
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