Identification guide · Metamorphic Rocks
How to Identify Anthracite
Anthracite is usually black and steel gray with a submetallic luster and is opaque. It has a Mohs hardness of 2.5. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Its streak is black to dark gray. It is most often confused with Shungite, Jet, and Coal; the tests below separate them.
Anthracite identification checklist
| Color | Black, Steel gray | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Submetallic | Turn it under a lamp: a true metallic shine reflects like polished metal and stays opaque at thin edges. |
| Transparency | Opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 2.5 | A copper coin (Mohs 3.5) scratches it, but a fingernail does not. |
| Streak | Black to dark gray | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | None | |
| Fracture | Conchoidal to uneven | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 1.5 | Noticeably light in the hand for its size (specific gravity about 1.5). |
Anthracite look-alikes and how to tell them apart
Shungite is harder (Mohs 3.5) than Anthracite (Mohs 2.5), so Shungite will scratch Anthracite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Anthracite vs Shungite →
Both sit near Mohs 2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Anthracite vs Jet →
Both sit near Mohs 2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Anthracite vs Coal →
Slate is harder (Mohs 3.5) than Anthracite (Mohs 2.5), so Slate will scratch Anthracite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
Field tips
- 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.
Anthracite identification FAQ
How can you tell if a rock is Anthracite?
Check the color (black and steel gray), the submetallic luster, a Mohs hardness of 2.5 and a black to dark gray streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Anthracite?
Anthracite has a Mohs hardness of 2.5. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
What is the difference between Anthracite and Shungite?
Anthracite (Mohs 2.5, submetallic luster) and Shungite (Mohs 3.5, submetallic luster) look alike, but hardness, streak and heft usually separate them. See the full Anthracite vs Shungite comparison for a side-by-side table.
Is Anthracite worth anything?
Entry-level Anthracite specimens sell for around $1, typical collector pieces about $8, and premium examples $50 or more depending on size, quality and locality.
What color is Anthracite?
Anthracite is most often black and steel gray. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
