mineral
Limonite Nodules / Goethite
Hydrated Iron Oxide-Hydroxide (FeO(OH)·nH2O / Fe2O3·nH2O)
Hardness: 4.0 - 5.5 on the Mohs scale. Color: Yellowish-brown, ochre, dark brown to black. Luster: Earthy, submetallic, to silky. Crystal structure: Amorphous or microcrystalline (pseudomorphous after other minerals). Cleavage: None (fractures unevenly). Specific gravity: 2.7 - 4.3.
- Hardness
- 4
- Color
- Yellowish-brown, ochre, dark brown to black
- Luster
- Earthy, submetallic, to silky
Identified More mineral →
Explore Limonite Nodules / Goethite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 4.0 - 5.5 on the Mohs scale. Color: Yellowish-brown, ochre, dark brown to black. Luster: Earthy, submetallic, to silky. Crystal structure: Amorphous or microcrystalline (pseudomorphous after other minerals). Cleavage: None (fractures unevenly). Specific gravity: 2.7 - 4.3.
Formation & geological history
Formed through the secondary weathering and oxidation of primary iron-bearing minerals (like pyrite, magnetite, or siderite) in hydrothermal veins, sedimentary iron formations, and soil profiles.
Uses & applications
Historically used as a natural mineral pigment (yellow ochre, umber), as a low-grade iron ore, and collected by rockhounds as botryoidal or nodular mineral specimens.
Geological facts
Limonite is not a true discrete mineral species, but rather a natural aggregate of related hydrated iron oxides, most commonly goethite and lepidocrocite. It often forms striking botryoidal, mammillary, or stalactitic crusts and nodules.
Field identification & locations
Easily identified in the field by its characteristic yellowish-brown to rust-brown streak on an unglazed porcelain plate. Found worldwide, including weathering zones in iron-rich geological regions of South America.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Soil with Mineral Detritus and Quartz Fragments
Regolith / Silicate Mineral Aggregate
sedimentary
Limonite / Goethite (Iron Ore Mineral nodule)
FeO(OH)·nH2O / FeO(OH)
mineral
Septarian Pebble
Septarian nodule / Concretion
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral