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Topic: Goethite

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Goethite may also be precipitated by groundwater or in other sedimentary conditions, or form as a primary mineral in hydrothermal deposits.
MARATHON COUNTY: Goethite is abundant in vugs in the pegmatites of the Wausau pluton.
MONROE COUNTY: Goethite is found as a cement in the conglomerates of the Windrow formation found in several areas in the county.
www.uwrf.edu /~W1014120/goethite.htm   (1195 words)

 Kinetics of Arsenic Adsorption on Goethite in the Presence of Sorbed Silicic Acid -- Waltham and Eick 66 (3): 818 -- ...
Kinetics of As adsorption on goethite at pH = 4 in the presence and absence of silicic acid, (a) As(III) and silicic acid, (b) As(V) and silicic acid.
Kinetics of As adsorption on goethite at pH = 8 in the presence and absence of silicic acid, (a) As(III) and silicic acid, (b) As(V) and silicic acid.
Kinetics of As adsorption on goethite at pH = 6 in the presence and absence of silicic acid, (a) As(III) and silicic acid, (b) As(V) and silicic acid.
soil.scijournals.org /cgi/content/full/66/3/818   (4027 words)

 GOETHITE Chapter 22. Oxides and hydroxides
Goethite is invariably brown; much local material is fibrous in habit, but some occurs as well-crystallized, bladed crystals in subparallel to divergent fasicles (Figure 22-56).
It was found in the oxidized zone at the north end of the Franklin Mine, in the Buckwheat Dolomite, and as a matrix for secondary copper carbonates on the 200 level.
At Sterling Hill, goethite is common in the oxidized material from the surface pit workings, occurring as hollow nodules associated with hetaerolite, chalcophanite, and hemimorphite.
franklin-sterlinghill.com /dunn/ch22/goethite.stm   (214 words)

 Brown Ochre (Goethite) | Natural Pigments
Goethite was named for Johann Wolfgang von Goethe (1749-1832), a German philosopher and poet who also was a mineralogist.
The most intensive red tones are obtained as a result of calcining goethite at a temperature between 500-600°C. The change in color is directly related to the dehydration of goethite and its transformation into hematite.
Goethite is not considered toxic but care should be used in handling the dry powder pigment so as not to inhale the dust.
www.naturalpigments.com /detail.asp?PRODUCT_ID=460-50S   (853 words)

 Kinetics of Chromate Adsorption on Goethite in the Presence of Sorbed Silicic Acid -- Garman et al. 33 (5): 1703 -- ...   (Site not responding. Last check: 2007-10-12)
Kinetics of chromate (0.05 mM) adsorption on goethite in the presence and absence of sorbed silicic acid.
Kinetics of chromate (0.10 mM) adsorption on goethite in the presence and absence of sorbed silicic acid.
Kinetics of arsenic adsorption on goethite in the presence of sorbed silicic acid.
jeq.scijournals.org /cgi/content/full/33/5/1703   (3076 words)

 Iconofile Store: Product: Goethite
Goethite is the yellow compound in mineral pigments known as ochre, sienna and umber.
Goethite with different quantities of hydrated iron oxide forms the range of yellow to brown hues found in natural mineral formations.
Ochres are chiefly composed of different hydrated iron oxides in varying amounts with goethite forming the major constituent, together with clay, sand, chalk, gypsum, barites and occasionally silica.
www.iconofile.com /storefront.asp?page=Goethite   (474 words)

 Goethite - Wikipedia, the free encyclopedia
Goethite often forms through the weathering of other iron-rich minerals, and thus is a common component of soils.
Goethite is found all over the planet, usually in the form of concretions, stalactitic formations, oolites (a form consisting of tiny round grains cemented together), reniform (kidney shapes) or botryoidal (globular, like bunches of grapes) accumulations.
Significant deposits of goethite are found in England, Cuba, and Michigan, Minnesota, Missouri, Colorado, Alabama, Georgia, Virginia, and Tennessee in the United States.
en.wikipedia.org /wiki/Goethite   (431 words)

 Sorption of Iron-Cyanide Complexes on Goethite in the Presence of Sulfate and Desorption with Phosphate and Chloride -- ...   (Site not responding. Last check: 2007-10-12)
Sorption of Iron–Cyanide Complexes on Goethite in the Presence of Sulfate and Desorption with Phosphate and Chloride
Sorption of iron–cyanide complexes on goethite in the presence and absence of equimolar amounts of sulfate and sorption of sulfate in the presence of iron–cyanide complexes as influenced by pH (a, ferricyanide; b, ferrocyanide).
Protonation of phosphate on the surface of goethite as studied by CTR–FTIR and electrophoretic mobility.
jeq.scijournals.org /cgi/content/full/31/3/745   (3383 words)

 Connaissances: Goethite
I first encountered the mineral Goethite when I was studying the Lower Greensand, a geological formation of southern England deposited during the Cretaceous period some 100 million years ago.
Goethite ooids are rarer today and form by the accretion of iron minerals on the sea floor, rather than calcium carbonate.
Goethite is the only mineral named after a poet.
connaissances.blogspot.com /2006/02/goethite.html   (916 words)

 Goethite, rock, crystal, mineral, gem stone, birth stones - mineralgallery
In fact much of the ocherous brown ferric oxide described as limonite is composed in a large part of crystaline goethite.
Limonite has a yellowish brown streak and a vitreous luster which, together with the lack of cleavage, serves to distinguish it from goethite.
Goethite occurs as a secondary mineral in the oxidation zone of veins containing iron bearing minerals.
www.mineralgallery.co.za /goethite.htm   (201 words)

 Crayton Yapp   (Site not responding. Last check: 2007-10-12)
Although goethite is extremely insoluble in oxidizing environments at values of pH characteristic of most low temperature terrestrial environments, our research on a modern system indicates that there is apparently continuous, biologically-mediated dissolution and re-precipitation of goethite in active, wet, oxidized soils.
Data from goethite formed in that ancient, wet, tropical environment, indicate that fluxes of soil CO2 arising from biological activity (respiration) may have been as high as 10 millimoles of CO2 per square meter per hour.
For example, formation of goethite as a consequence of pyrite oxidation in the presence of ambient limestone represents a circumstance in which mixing between the CO2 from "upstream soils" and CO2 from local dissolution of limestone is recorded by the Fe(CO3)OH component in the goethite.
www.smu.edu /geology/yapp.htm   (1464 words)

 From Nanodots to Nanorods: Oriented aggregation and magnetic evolution of nanocrystalline goethite
Goethite is a common iron oxyhydroxide and an important mineral in the biogeochemical cycle of iron at the Earth's surface.
Perhaps this is because past studies have traditionally used needle-shaped goethite particles that are substantially larger than the goethite nanoparticles commonly observed in nature.
High-resolution transmission electron microscopy and low-temperature magnetometry of synthetic goethite nanocrystals show that when aqueous suspensions are aged at 90°C, the nanocrystals grow almost exclusively by oriented aggregation of 3–4 nm primary nanocrystals.
www.agu.org /pubs/crossref/2003/2003GL017021.shtml   (294 words)

 The Effect of Oxyanions on the Oxalate-Promoted Dissolution of Goethite -- Eick et al. 63 (5): 1133 -- Soil Science ...
It is proposed that chromate and arsenate inhibit goethite dissolution
dissolution of goethite, adsorption of chromate or arsenate
Manceau A., Charlet L. The mechanism of selenate adsorption on goethite and hydrous ferric oxide.
soil.scijournals.org /cgi/content/full/63/5/1133   (4096 words)

 Goethite   (Site not responding. Last check: 2007-10-12)
This is polished section of Goethite from near Socorro, New Mexico.
More commonly goethite occurs as aggregates of acicular crystals in divergent sprays, reniform or stalactitic masses or radially fibrous.
BREAKABILITY Goethite has a splintery fracture when it forms fibrous masses, otherwise is brittle with an uneven fracture.
www.gc.maricopa.edu /earthsci/imagearchive/goethite.htm   (105 words)

Synthetic and natural goethites display a variety of particle morphologies that are dependent on solution conditions during formation (Schwertmann 1990).
Factors influencing goethite morphology include pH and the presence or absence of specifically adsorbing ions in solution.
In order to facilitate rapid preliminary comparison of synthetic goethite samples, we have investigated the use of powder XRD to derive similar qualitative information via the influence of preferred orientation during sample preparation.
www.uga.edu /~srel/Reprint/2220.htm   (465 words)

 Kinetic Study of Goethite Formation from Ferrihydrite in Alkaline Medium
The kinetics of goethite formation from ferrihydrite was studied colorimetrically in the initial pH range of 11.00-12.20 and at temperatures varying between 40 and 80
It was shown that the rate of goethite crystallization is significantly influenced by the aging temperature and by the initial pH.
Both the shrinking core model results and the high value of the activation energy favor the hypothesis that the rate of the ferrihydrite transformation process is controlled by the surface chemical reaction.
pubs.acs.org /cgi-bin/abstract.cgi/iecred/2002/41/i21/abs/ie010931z.html   (203 words)

 Using goethite-bound carbon isotope signatures to monitor soil-water chemistry in a forested watershed: Panola ...   (Site not responding. Last check: 2007-10-12)
The study will be performed using goethite forming in soil/saprolite found overlying granite terrains in the Piedmont of Georgia.
It is optimal for the test because of the abundance of soil goethite found and it is part of the large-scale U.S. Geological Survey (USGS) investigation known as the Water, Energy and Biogeochemical Budget (WEBB) Program.
This work has important implications for the viability of using carbon-bound goethite as a proxy for paleo-atmospheric CO The extraction line for this work is a new generation micro CO system designed for multiple step-wise extractions.
www.gly.uga.edu /schroeder/schroeNSF96.html   (361 words)

 SPACE.com -- On Mars: Earth-Like Clouds and a New Type of Rock
The Spirit rover, ambling through the Columbia Hills at the fringe of the Gusev crater, has uncovered a riot of rock forms and chemistries, including a mineral called goethite, which had not been found on Mars before.
Goethite is common on Earth and forms only in the presence of water, though the water can be liquid, frozen or vaporous, said Goestar Klingelhoefer of the Johannes Gutenberg University in Germany.
A chunk of terrestrial goethite about the size of a can of tomato soup, passed around during a press conference, was fl and shiny and weighed about as much as a can-and-a-half of tomato soup.
www.space.com /missionlaunches/rover_update_041213.html   (1056 words)

 New Stuff Weekly Update
It was a very popular collecting locality in the late 40s and early 50s after which people, having collected the easily accessible material, came to the conclusion that the locality was basically “played” out.
They worked this layer for the better part of three weeks, on a part time basis, producing some really great clusters of goethite pseudos.
The project was, however, abandoned because of problems involving the cleaning and preparation of the specimens.
www.hpminerals.com /pollyp/goethite.htm   (270 words)

 Microbial Reduction of Structural Fe(III) in Illite and Goethite   (Site not responding. Last check: 2007-10-12)
The starting material (both goethite and illite) contained 6% (w/w) total Fe, and 82% of the total Fe was Fe(III).
Approximately 30% of total Fe was associated with goethite.
Modeling of Mössbauer spectra of the bioreduced material indicated that both goethite and illite were reduced but to a different extent.
pubs.acs.org /cgi-bin/sample.cgi/esthag/2003/37/i07/abs/es020919d.html   (327 words)

and goethite in loess and paleosol samples is reported.
concentration of hematite and goethite in the Chinese loess
of wt.% hematite and goethite and have correlation coefficients
ccm.geoscienceworld.org /cgi/content/abstract/50/2/208   (320 words)

 Goethite in Colorado
Not many goethite specimens are seen from its ore producing days, but this piece and several others were collected a few years ago by two friends of Dave Bunk while exploring the mine.
Spray of brown goethite crystals from the Lake George area.
Great looking sprays of goethite from the Coil Claims, Lake George District, Park County.
www.peaktopeak.com /colorado/mineral.php3?mineralid=50   (57 words)

 Reduction of U(VI) in goethite (a-FeOOH) suspensions by a dissimilatory metal-reducing bacterium
Reduction of U(VI) in goethite (a-FeOOH) suspensions by a dissimilatory metal-reducing bacterium
presence of goethite under conditions where the aqueous composition was controlled to vary U speciation and
the U(VI) associated with a synthetic metaschoepite was reduced by the organism in the presence of goethite
www.uga.edu /srel/Reprint/2474.htm   (361 words)

 Delaware Mineralogical Society Story Pages: Sunny Brook Crick Goethite by Joe Dunleavy
There is always plenty of Goethite and Limonite in the banks of the crick but I make it a habit not to dig in the banks and cause erosion problems.
The best level to search for the better Goethite is about 6 feet under the topsoil.
If you are in the area and want some nice Botryoidal Goethite or just plain old Goethite, you should give this crick a try.
home.comcast.net /~delminsociety2/sunnybrook.htm   (931 words)

 Oxides, Rocks and Minerals, Kentucky Geological Survey
Goethite usually occurs in massive, stalactitic, fibrous, or botryoidal (grape-like) forms, and exhibits radial growth.
In western Kentucky, goethite is associated with limonite in porous earthy masses called bog iron ore. Goethite is an ore of iron in some areas; it is noncommercial in Kentucky.
Hematite occurs in platy, compact, granular, or earthy masses.
www.uky.edu /KGS/rocksmn/oxides.htm   (585 words)

These samples of goethite are displayed in the Smithsonian Museum of Natural History.
Goethite is an oxide mineral of iron with the composition FeO(OH).
This sample is about 8x7 cm and it is from Park County, Colorado.
hyperphysics.phy-astr.gsu.edu /hbase/minerals/goethite.html   (47 words)

 USGS Spectroscopy Lab - Clark et. al. 2003 Spectral Library splib05a
Very weak, broad goethite reflections indicate poor crystallinity and possible low abundance (compare with "pure" goethite, GDS-134).
Significant quartz contamination, quartz is 50% coated by goethite.
Large goethite grains are 50% coated with smaller goethite grains.
pubs.usgs.gov /of/2003/ofr-03-395/DESCRIPT/M/goethite_ws220.html   (113 words)

 Goethite after Siderite in Colorado
Goethite after Siderite in the South Central Region
Plate of 2-4 mm microcline crystals with several goethite pseudomorphs after siderite crystals up to 1.5 cm.
Blocky, euhedral crystals of goethite that have pseudomorphed from siderite (most likely), retaining its form, have grown around a single smoky quartz crystal.
www.peaktopeak.com /colorado/mineral.php3?mineralid=52   (87 words)

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