RocksdayGoethite vs Manganite
The quickest way to tell Goethite from Manganite: Goethite leaves a yellowish brown streak; Manganite leaves brown.
An iron oxyhydroxide forming dark bubbly or velvety masses, and the main component of rust.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Black manganese oxide-hydroxide in striated prisms. The streak is brown, not black.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Streak (rub on unglazed porcelain): Goethite leaves a yellowish brown streak; Manganite leaves brown.
Key differences
- Goethite is usually brown and fibrous, with a yellow-brown streak.
Side by side
| Property | Goethite | Manganite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 5–5.5 | 4 |
| Luster | Adamantine to silky | Submetallic |
| Streak | Yellowish brown | Brown |
| Colors | Brown, Black, Yellow | Black, Gray |
| Crystal system | Orthorhombic | Monoclinic |
| Specific gravity | 3.3–4.3 | 4.3–4.4 |
| Formula | FeO(OH) | MnO(OH) |
| Found in | Pikes Peak, Colorado; Cornwall, England | Ilfeld, Harz, Germany; Cornwall, England |
Properties that are the same for both are grayed out.
How to identify goethite
- Black-brown botryoidal masses, often with iridescent tarnish.
- Yellow-brown streak.
- Radiating fibers when broken.
Crystal system: Orthorhombic
Full Goethite guide →How to identify manganite
- Black prisms with lengthwise striations.
- Reddish-brown to dark brown streak.
- Hardness 4 — a knife scratches it.
Crystal system: Monoclinic
Full Manganite guide →More comparisons
Frequently asked questions
What is the difference between goethite and manganite?
Goethite is a mineral with a Mohs hardness of 5–5.5 and an adamantine to silky luster, usually brown, black or yellow. Manganite is a mineral with a Mohs hardness of 4 and a submetallic luster, usually black or gray.
How can you tell goethite from manganite?
Goethite leaves a yellowish brown streak; Manganite leaves brown. Goethite is usually brown and fibrous, with a yellow-brown streak.
Could you tell them apart from a blurry close-up?
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