Identification guide · Hydroxide Minerals
How to Identify Limonite
Limonite is usually yellowish brown, brown, and dark brown with a earthy luster and is opaque. It has a Mohs hardness of 4.5. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Its streak is yellowish brown. It is most often confused with Goethite, Sandstone, and Limestone; the tests below separate them.
Limonite identification checklist
| Color | Yellowish brown, Brown, Dark brown, Ochre yellow | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Earthy | Compare a fresh surface with glass and metal; this luster is softer than either. |
| Transparency | Opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 4.5 | A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. |
| Streak | Yellowish brown | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | None | |
| Fracture | Earthy to conchoidal | Broken surfaces show smooth, curved, shell-like scoops. |
| Specific gravity | 3.6 | Heavier than it looks (specific gravity about 3.6). |
| Crystal system | Amorphous |
Limonite look-alikes and how to tell them apart
Both sit near Mohs 4.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Limonite vs Goethite →
Sandstone is harder (Mohs 6) than Limonite (Mohs 4.5), so Sandstone will scratch Limonite and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Limonite vs Sandstone →
Limonite is harder (Mohs 4.5) than Limestone (Mohs 3), so Limonite will scratch Limestone and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Limonite vs Limestone →
Both sit near Mohs 4.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Limonite vs Laterite →
Field tips
- Look for brown to yellowish-brown earthy or botryoidal masses that lack crystal faces of their own.
- Limonite always leaves a distinctive yellowish-brown streak, a key identifying feature.
- Distinguish it from hematite by its yellow-brown rather than red streak, and recognize cube-shaped pseudomorphs after pyrite.
Limonite identification FAQ
How can you tell if a rock is Limonite?
Check the color (yellowish brown, brown, dark brown, and ochre yellow), the earthy luster, a Mohs hardness of 4.5 and a yellowish brown streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Limonite?
Limonite has a Mohs hardness of 4.5. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
What is the difference between Limonite and Goethite?
Limonite (Mohs 4.5, earthy luster) and Goethite (Mohs 5–5.5, adamantine to dull/earthy, silky luster) look alike, but hardness, streak and heft usually separate them. See the full Limonite vs Goethite comparison for a side-by-side table.
Is Limonite worth anything?
Entry-level Limonite specimens sell for around $3, typical collector pieces about $20, and premium examples $120 or more depending on size, quality and locality.
What color is Limonite?
Limonite is most often yellowish brown, brown, dark brown, and ochre yellow. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
