Comparison · Metamorphic Rocks vs Sedimentary Rocks
Anthracite vs Coal
Anthracite and Coal are easy to confuse. Both sit near Mohs 2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Anthracite and Coal
- Both sit near Mohs 2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Anthracite leaves a black to dark gray streak on unglazed porcelain, Coal leaves black to brownish black.
- Luster is different: Anthracite is submetallic while Coal is dull (lignite) to vitreous (anthracite).
- Hold a thin edge to the light: Anthracite is opaque, Coal is Opaque.
- They overlap in black, but Anthracite also comes in gray and Coal also comes in brown.
Anthracite vs Coal properties
| Property | Anthracite | Coal |
|---|---|---|
| Type | Metamorphic Rocks | Sedimentary Rocks |
| Mohs hardness | 2.5 | 1–2.5 |
| Luster | submetallic | Dull (lignite) to vitreous (anthracite) |
| Streak | Black to dark gray | Black to brownish black |
| Transparency | opaque | Opaque |
| Specific gravity | 1.5 | 1.1–1.8 |
| Crystal system | varies | Amorphous |
| Common colors | Black, Steel gray | Black, Brownish black |
| Rarity | common | common |
| Typical specimen value | $1–$50+ | $1–$75+ |
Which is more valuable?
Coal is usually the more valuable of the two: a typical collector specimen runs about $10 against $8 for Anthracite, and premium Coal can reach $75 or more.
About Anthracite
Anthracite is a hard, shiny, high-carbon coal. It often looks black, compact, lightweight for its size, and glassy to submetallic.
About Coal
Coal is a combustible sedimentary rock composed mostly of carbon along with hydrogen, oxygen, and trace minerals, formed from the compaction and chemical alteration of ancient plant material. Unlike true minerals, it lacks a fixed crystal structure or chemical formula, and its properties vary with rank, the degree of transformation from the original plant matter. It ranges from soft, brown lignite to hard, glossy anthracite.
Anthracite vs Coal FAQ
Is Anthracite the same as Coal?
No. Anthracite is a metamorphic rock while Coal is a sedimentary rock. Both sit near Mohs 2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Anthracite from Coal?
Both sit near Mohs 2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Anthracite leaves a black to dark gray streak on unglazed porcelain, Coal leaves black to brownish black. Luster is different: Anthracite is submetallic while Coal is dull (lignite) to vitreous (anthracite).
Which is harder, Anthracite or Coal?
Anthracite is harder: Mohs 2.5 against Mohs 1–2.5 for Coal.
Which is more valuable, Anthracite or Coal?
Coal is usually the more valuable of the two: a typical collector specimen runs about $10 against $8 for Anthracite, and premium Coal can reach $75 or more.
