Hydrated iron oxyhydroxide mixture forming the typical rusty brown weathering product of iron-bearing minerals. Not a true mineral. Color: Yellow-brown, rusty brown, black. Luster: Earthy to submetallic. Streak: Yellowish-brown. Cleavage: None. Hardness: 4-5.5. Transparency: Opaque. Crystal system: Amorphous. Chemical formula: FeO OH ·nH₂O. Specific gravity: 2.7-4.3. Formation: Forms by weathering and oxidation of iron-bearing minerals such as pyrite, magnetite, and siderite. Common geological settings: Worldwide; found as the typical brown rusty coating on weathered rocks containing iron minerals. Common look-alikes and related entries: Hematite, Goethite, Siderite.
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
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GeoMiner
Last updated
2026-03-30T14:37:42.327987+00:00
Review status
Published; not independently peer-reviewed
IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
Hydrated iron oxyhydroxide mixture forming the typical rusty brown weathering product of iron-bearing minerals. Not a true mineral.
How can you identify Limonite?
Compare several properties rather than relying on colour alone. This entry records colour: Yellow-brown, rusty brown, black; lustre: Earthy to submetallic; streak: Yellowish-brown; Mohs hardness: 4-5.5; cleavage: None; crystal system: Amorphous; transparency: Opaque. Confirm an important identification with additional field tests or qualified laboratory work.
How does Limonite form?
Forms by weathering and oxidation of iron-bearing minerals such as pyrite, magnetite, and siderite.
Where is Limonite commonly found?
Worldwide; found as the typical brown rusty coating on weathered rocks containing iron minerals.
What is Limonite commonly confused with?
Limonite may be confused with Hematite, Goethite, Siderite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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