mineral
Goethite
Goethite (FeO(OH))
AI-generated identification · may be incorrectHardness: 5-5.5 (Mohs scale), Color: Dark brown to black with iridescent or metallic luster, Crystal Structure: Orthorhombic, Streak: Brownish-yellow.
- Hardness
- 5-5
- Streak
- Brownish-yellow
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Physical properties
Hardness: 5-5.5 (Mohs scale), Color: Dark brown to black with iridescent or metallic luster, Crystal Structure: Orthorhombic, Streak: Brownish-yellow.
Formation & geological history
Formed as a weathering product of iron-bearing minerals in soil and oxidation zones of ore deposits. Can also form by direct inorganic or biogenic precipitation in marine and spring waters.
Uses & applications
An important iron ore. Often used as a pigment (ochre). Collected for its unique botryoidal (grape-like) habits and iridescent surface coatings.
Geological facts
Named after Johann Wolfgang von Goethe, the German polymath. It is a primary component of iron rust and bog iron ore.
Field identification & locations
Identified by its yellow-brown streak, metallic to sub-metallic luster, and frequent association with limonite. Common in Australia, Brazil, and the USA (Great Lakes region).
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Sandstone (with potential mineral staining/concretions)
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Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
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Granite
Granite (Phaneritic intrusive igneous rock)
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Septarian Pebble
Septarian nodule / Concretion
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