Back Goethiet Afrikaans غوتيت Arabic Hetit Azerbaijani Гётыт Byelorussian Гьотит Bulgarian Goethita Catalan Goethit Czech Goethit Danish Goethit German Γκαιτίτης Greek
| Goethite | |
|---|---|
 | |
| General | |
| Category | oxide minerals hydroxide subgroup |
| Formula (repeating unit) | α-FeO(OH) |
| IMA symbol | Gth[1] |
| Strunz classification | 4.FD.10 |
| Crystal system | Orthorhombic |
| Crystal class | Dipyramidal (mmm) H–M symbol: (2/m 2/m 2/m) |
| Space group | Pbnm |
| Identification | |
| Color | Yellowish to reddish to dark brown or black |
| Crystal habit | radial acicular, mammillary, botryoidal, stalactitic, massive, as encrustation, as pseudomorph; may be banded or iridescent |
| Cleavage | Perfect {010} |
| Fracture | Uneven to splintery |
| Mohs scale hardness | 5.0–5.5 |
| Luster | Adamantine to dull |
| Streak | Brown, brownish yellow to orange yellow |
| Specific gravity | 3.3–4.3 |
| Refractive index | Opaque to sub-translucent |
| Fusibility | Fusible at 5–5.5 |
| Solubility | HCl soluble |
| Other characteristics | weakly magnetic |
| References | [2][3][4][5] |
Goethite (/ˈɡɜːrtaɪt/,[6][7] US also /ˈɡoʊθaɪt/[8][9]) is a mineral of the diaspore group, consisting of iron(III) oxide-hydroxide, specifically the α-polymorph. It is found in soil and other low-temperature environments such as sediment. Goethite has been well known since ancient times for its use as a pigment (brown ochre). Evidence has been found of its use in paint pigment samples taken from the caves of Lascaux in France. It was first described in 1806 based on samples found in the Hollertszug Mine in Herdorf, Germany.[4] The mineral was named after the German polymath and poet Johann Wolfgang von Goethe (1749–1832).
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20th ed.). Wiley. ISBN 0-471-80580-7.
- ^ Barthelmy, David (2012). "Goethite Mineral Data". Mineralogy Database. Retrieved 8 April 2022.
- ^ a b Goethite, Mindat.org
- ^ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Goethite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Archived (PDF) from the original on 2022-10-09. Retrieved 14 March 2022.
- ^ "goethite". Lexico UK English Dictionary. Oxford University Press. Archived from the original on August 5, 2021.
- ^ "goethite". Merriam-Webster.com Dictionary. Merriam-Webster.
- ^ "goethite". Dictionary.com Unabridged (Online). n.d.
- ^ "goethite". The American Heritage Dictionary of the English Language (5th ed.). HarperCollins.