mineral

Limonite/Goethite

Goethite: alpha-FeO(OH), Limonite: FeO(OH)nH2O

Hardness: 4 to 5.5 (variable); Color: Yellowish-brown to dark brown; Luster: Dull, earthy, or submetallic; Crystal Structure: Amorphous/Orthorhombic; Cleavage: None/Indistinct; Specific Gravity: 2.7 to 4.3.

Hardness: 4 to 5
Color: Yellowish-brown to dark brown
Luster: Dull, earthy, or submetallic

Identified May 1, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through the industrial weathering of iron-rich minerals such as magnetite, hematite, or pyrite. It is common in the oxidation zones of ore deposits and as a precipitate in bogs (bog iron).

Uses & applications

Historically used as a common iron ore and as a natural pigment (brown ochre). It is also valued by collectors for its botryoidal forms and as a marker for metal deposits.

Geological facts

Limonite is not a true mineral but a mixture of hydrated iron oxide minerals. It has been used by humans as a pigment since prehistoric times, appearing in cave paintings at Lascaux.

Field identification & locations

Identify by its characteristic yellowish-brown streak on a porcelain plate and its earthy, rusty appearance. Often found in weathered outcrops or near mine tailings.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral