Goethite


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Related to Goethite: limonite

goethite

[′gə‚tīt]
(mineralogy)
FeO(OH) A yellow, red, or dark-brown mineral crystallizing in the orthorhombic system, although it is usually found in radiating fibrous aggregates; a common constituent of natural rust or limonite. Also known as xanthosiderite.

Goethite

 

(named in honor of the poet J. W. Goethe), a mineral of the iron hydroxide group; chemical composition FeOOH. It contains admixtures of manganese and aluminum, as well as surplus adsorbed water (hydrogoethite). The mineral crystallizes in a rhombic system, forming columnar, needle-like crystals and their growths, sinter aggregates, and powdery and earthy masses mixed with hydrogoethite, hydrohematite, and other minerals (so-called limonites and bog iron ores). The color is brownish yellow to dark reddish brown. Needlelike crystals of goethite gathered into bundles are called needle ironstone. The hardness of goethite on the mineralogical scale is 5-5.5; density, 4,140-4,280 kg/m3. Goethite in crystals sprouting quartz, together with iron sulfides and other sulfides, is found in hydrothermal deposits, which are numerous in the USSR and abroad. The widest distribution of goethite in nature is associated with supergene and sedimentary deposits of iron ores.

G. P. BARSANOV

References in periodicals archive ?
Using a millimeter wave detector, we discovered that this antiferromagnetic absorption only occurs within narrow frequency ranges in the terahertz region of the electromagnetic spectrumyielding spectral fingerprints unique to goethite and hematite, and in turn, iron corrosion.
The white gravels, thought initially to be bauxite fragments, contained mostly quartz and minor hematite and goethite.
The lack of symmetry displayed by the DSC curves, kaolinite dehydroxylation temperatures (500 - 650 [degree]C) together with goethite dehydroxylation reactions observed in the studied kaolins, suggests moderate degrees of crystallinity (Saviano et al.
The proportions of the different Fe oxides phases identified in the XRD analyses of the concentrated Fe oxides fraction were estimated from the areas of the 110 reflection plane of goethite (Gt-110), the 012 plane of hematite (Hm-012) and the 220 plane of maghemite (Mh-220) that were obtained using the Siemens DIFFRAC plus-EVA computer program.
The haematite and goethite occurrences are interpreted to result from alteration and enrichment of the magnetite-bearing BIF, particularly in areas of complex folding.
Key words: Mineralogical, petrographical, lithofacies, Salt Range, Permian, Cretaceous, kaolinite, goethite, boehmite, gibbsite, dickite, glauconite, chamosite, chlorite, nacrite, micrite, microclasts.
We obtained hematite, magnetite, and goethite iron oxide pigment powders from Atlantic Equipment Engineers, [dagger] with purities of greater than 90 % and particle sizes from 1 m to 5 m.
After the TAPM samples were extracted for 160h, the supernatant from the reaction vessel was centrifuged at 9000G for 7min to remove any non-dissolved particles present in the system; 200mL of supernatant was then transferred into a new reaction vessel together with sufficient mass of either kaolinite or goethite to make 100-[m.
First, the group varied the acidity (pH), salinity and goethite levels of the water, to see how fast the arsenic reacted with the goethite.
At the Cueva (Cave) Anton, the scientists unearthed a pierced king scallop shell painted with orange pigment made of yellow goethite and red hematite collected some five kilometers from that site.
Some would say that the world's most attractive specimens of goethite are the fan-sprays of lustrous, brownish red bladed crystals from miarolitic cavities in the granite of the Pikes Peak batholith, Colorado.
Taylor, The isomorphical replacement of iron by aluminum in soil goethite, J.