Goethite (FeO(OH)) is iron hydroxide — the principal iron mineral of laterite, gossan, and bog iron deposits. Named after the German polymath Goethe, it forms in low-temperature oxidized environments as botryoidal, fibrous, or radiating acicular masses. Yellow streak distinguishes Goethite from hematite. Cornwall (England) and Pikes Peak (Colorado) supply collector specimens.
Key Facts
- Mohs hardness 5–5.5.
- Orthorhombic; acicular needles, botryoidal aggregates, fibrous masses.
- Yellow-brown streak diagnostic.
- Major iron mineral of lateritic and gossan oxidation profiles.
- Pseudomorphic replacements after pyrite are common collector specimens.
Notable Localities
Cornwall (England), Pikes Peak (Colorado), and Ouro Preto (Brazil) yield collector botryoidal specimens. Hubei and Hunan host massive Chinese deposits.
Found at these Localities
- Rapid Creek (Yukon) (育空地区急流溪磷酸盐产地)
- Siegerland District (西格兰铁矿区)
- Mina Ojuela, Mapimí (马皮米奥胡埃拉矿)
- Cornwall Mining District (康沃尔矿区)
- Ouro Preto Region (欧鲁普雷图矿区)
- Hubei (湖北)
- Hunan (湖南)
- Eastern Brazilian Pegmatite Province (巴西东部伟晶岩省)
