|Kristallklasse||IV/F.06-30 (after Strunz)|
|color||lightyellow to dark-brown|
|hardness||5 to 5.5|
|gloss||diamond gloss, Metallglanz, silk gloss|
|opacity||translucently to obscurely|
|break||unevenly to muschelig|
|Habitus||radialstrahlig, needle-shaped to prismatisch, trust-bend|
|frequent crystal faces||___|
of the Zes-axis
|2v z ~ ___|
Goethit or needle iron ore is a wide-spread in orthorombischen crystal system crystallizing hydroxide - mineral with the chemical composition FeO (OH), which is ranked mineralogically among the oxides. It has a hardness from 5 to 5.5, a lightyellow to dark-brown color and a yellow-brown line color.
Table of contents
the only well-known Varietät velvet screen. It forms kastanienbraune to ocher-yellow balls, which possess a including-like surface.
education and discovery sites
Goethit arise to usually substantial and have a radialor fibrous, sometimes also spherical structure. The crystalline form is usually sow-lies or nadelig. It forms during the oxidation decomposition of iron - for minerals such as magnetite or pyrite and occurs as primary mineral also in Hydrothermaladern; one finds it frequently in cavities of volcanic rocks as for example Pegmatit. After pyrite and other Eisensulfiden it forms and than sump and brown iron ore ( Limonit) occurs it for Pseudomorphosen also in sediment eras ore stores. Normal rust consists likewise mainly of Goethit.
Discovery sites in Germany are among other things victories and hearing living, in England Bottalack, Redruthand the county Cornwall, in Mexico Santa Eulalia, in Tschechien Příbram and in the US Federal State Colorado Florissant.
Goethit was proven in December 2004 of the space probe „mirror-image-guessed/advised “also on the Mars surface. NASA - Scientists rate this as one of the safest proofs for Water on the red planet, since Goethit forms only in connection with water.
meaning as raw material
the mineral was recognized first 1806 as independent type and designated after the German poet Johann Wolfgang von Goethe, who was also a mineral collecting tank. In the year 2004 it was determined by the space probe MER-A on Mars, whatit NASA for a proof of former water rated.
See also: List of minerals
- edition Dörfler: Minerals encyclopedia, fog publishing house, ISBN 3-89555-076-0