Goethite

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Goethite
FeO(OH) Orthorhombic



Goethite is found as an supergene oxidizing (weathering) product of many iron minerals. In the near surface, it was an important iron ore mineral developed over banded iron formations. It is found in sedimentary rocks as concretions and was mined from bog ore deposits. It is a component of limonite and is found in the weathered gossans of sulfide rich ore deposits and was used as a prospecting indicator.

Massive specimens of goethite are relatively common with a reniform, botyroidal or stalagtitic habit. These specimens are made of numerous acicular crystals and were found in Cornwall and the states of Michigan, Wisconsin and Minnesota in the USA. Individual crystals are rare, the best ones are found in pegmatites from Colorado. Goethite crystals also are found from many localities as crystals suitable for micromounting. or as inclusions in quartz. While the mineral is a yellow brown in color, iridescent coatings can result in aesthetic specimens. There are numerous good examples of goethite pseudomorphing other iron minerals, especially pyrite, marcasite and siderite.
[David Von Bargen 2011]

"Limonite" is nowadays just a general field term for earthy iron oxides, not a species name. So, although theoretically "limonites" could be composed of lepidocrocite, hematite, maghemite, various hydrous iron oxides or oxy-hydroxides, and even powdery jarosite-group species, they are most commonly composed of goethite, so it's fairly safe to label them that way, especially when the streak is yellow-brown, they show no magnetism, and they have been kept dry for a long time (after which the less stable hydrated oxides mostly alter into goethite anyway). I've had a lot of hard brown iron oxides x-rayed. Once in a while they turn out to be mainly hematite, like the christmas-tree shaped pseudos from Egypt, in spite of not having a very red streak, and once one locality turned out to be maghemite (I should have checked it with a magnet before wasting an XRD :( ) and another had a lot of jarosite in it. Never yet found a "limonite" that was lepidocrocite. Even if a sample turned out to be a goethite-bearing mixture, that wouldn't make a "goethite" label wrong.
[Alfredo Petrov 2011]

Goethite
Australia
South Australia, Olary, Kirkeeks Treasure Mine



Goethite
Australia
Tasmania, Dundas, Red Lead Mine



Goethite
Egypt
Matruh Governorate, Farafra Oasis

Goethite @ Marcasite 5.1cm tall	© Bracke

Goethite @ Marcasite 4.1cm wide	© Christian Bracke

Goethite @ Marcasite 5.8cm wide	© Weinrich

Goethite
France
Centre, Indre, Chaillac, Chaillac Mine

Goethite blades to 6mm	© Peter Haas

Goethite
France
Midi-Pyrénées, Ariège, Vicdessos, Sem, Le Rancié Mine




Goethite
Germany
Hesse, Odenwald, Bensheim, Roßbach, Link marble works




Goethite
Germany
North Rhine-Westphalia, Siegerland, Neunkirchen, Salchendorf, Pfannenberger Einigkeit Mine




Goethite
Germany
Rhineland-Palatinate, Siegerland, Herdorf

Goethite 7.2cm tall	© CCURTO09

Goethite
Hungary
Borsod-Abaúj-Zemplén Co., Rudabányai Mts., Rudabánya




Goethite
Hungary
Pest Co., Budai Mts., Budaörs, Frank Hill (Kakukk Hill)




Goethite
Ireland
Co. Wicklow, Blessington, Kilbride, Cloghleagh mine (Cloghlea mine)




Goethite
Italy
Piedmont, Torino Province, Canavese District, Léssolo, Cálea, Brosso Mine

Goethite FOV 2.2mm wide	© Castagneri

Goethite
Italy
Tuscany, Livorno Province, Elba Island, Porto Azzurro, Cape Arco Mine




Goethite
Italy
Tuscany, Livorno Province, Elba Island, Porto Azzurro, Cape Bianco Mine




Goethite
Madagascar
Antsiranana Province, Diana Region, Ambanja District, Ampasindava Peninsula, Befitina, Rare Earths Prospect




Goethite
Mexico
Chihuahua, Mun. de Aquiles Serdán, Santa Eulalia District

@ gypsum	© Lavinsky

Goethite
Mexico
Sonora, Mun. de Alamos, San Antonio




Goethite
Morocco
Meknès-Tafilalet Region, Er Rachidia Province, Taouz

Goethite forms the matrix for many secondary minerals from here.




Goethite
Morocco
Meknès-Tafilalet Region, Er Rachidia Province, Taouz, Four Man Mine

Goethite FOV 3cm wide	©

Goethite
Poland
Lower Silesia (Dolnośląskie), Jawor District, Stanisławów

Goethite 8cm wide	© G. van der Veldt

Goethite
Portugal
Castelo Branco District, Vila Velha de Rodão, Serra de Rodão, Tavila




Goethite
Portugal
Setúbal District, Grândola, Caveira Mine




Goethite
Portugal
Setúbal District, Grândola, Lousal Mine




Goethite
Portugal
Setúbal District, Santiago do Cacém, Cercal (Cercal do Alentejo), Serra da Mina

Goethite 5cm	© Martins da Pedra

.

Goethite FOV15mm	© Rui Nunes 2005

.

Goethite 14cm	© Martins da Pedra

Goethite
Slovakia
Košice Region, Slovenské Rudohorie Mts




Goethite
Slovakia
Košice Region, Slovenské Rudohorie Mts, Rožňavské Bystré

Goethite FOV 3cm	© Albert Russ

Goethite
Slovenia
Litija (Littai), Sitarjevec mine




Goethite
Spain
Andalusia, Huelva, Alosno, La Lapilla Mine

Goethite 5.2cm tall	© fabreminerals.com

Goethite
Spain
Andalusia, Huelva, Alosno, Tharsis, Filón Sur Mine

Goethite 10cm tall	© fabreminerals.com

Goethite 5cm wide	© Martins da Pedra

Goethite
Spain
Castile and Leon, Soria




Goethite
Switzerland
Wallis (Valais), Lötschen valley, Blatten




Goethite
UK
England, Bedfordshire, Leighton Buzzard, Munday's Hill Quarry




Goethite
UK
England, Cornwall, St Austell District, Lostwithiel, Restormel Royal Iron Mine




Goethite
UK
England, Cornwall, St Just District, St Just, Kenidjack Valley, Wheal Drea




Goethite
UK
England, Leicestershire, Stanton under Bardon, New Cliffe Hill Quarry




Goethite
UK
Wales, Cardiff, Bwlch-y-cwm, Blaengwynlais Quarry

Goethite after Pyrite	© J.Ralph

Goethite
USA
Alaska, Prince of Wales-Outer Ketchikan Borough, Prince of Wales Island, Copper Mountain




Goethite
USA
Arkansas, Polk Co., Shady, Coon Creek Mine




Goethite
USA
Colorado, El Paso Co., Pikes Peak, Sentinel rock, Mona Mine

Goethite @ Siderite 9.7cm	© Edwards Minerals

Goethite
USA
Colorado, Lake Co., Leadville District, Leadville




Goethite
USA
Colorado, Park and Teller Cos., Crystal Peak area

Goethite 17cm tall	© Christian Bracke

Goethite after Siderite? 5.5cm wide	© Weinrich

Goethite 5.9cm tall	© Rob Lavinsky

Goethite
USA
Colorado, Park Co., Lake George, Clarence Coil claim




Goethite
USA
Georgia, Lincoln Co., Graves Mountain




Goethite
USA
Michigan, Dickinson Co., Menominee iron range, Aragon Mine




Goethite
USA
Michigan, Iron Co.




Goethite
USA
Michigan, Iron Co., Menominee iron range, Stambaugh, Hiawatha Group, Hiawatha No. 1 Mine




Goethite
USA
Michigan, Marquette Co., Marquette iron range, Champion

Typical acicular crystals forming botyroidal masses in iron ore.




Goethite
USA
Michigan, Marquette Co., Marquette iron range, Humboldt Township, Bessie Mine




Goethite
USA
Michigan, Marquette Co., Marquette iron range, Morris-Lloyd, Lloyd Mine




Goethite
USA
Michigan, Marquette Co., Marquette iron range, Negaunee, Negaunee Mine




Goethite
USA
Michigan, Marquette Co., Marquette iron range, Palmer, Richmond Mine




Goethite
USA
Minnesota, St. Louis Co., Mesabi Range, Thunderbird Mine

Typical goethite vein.




Goethite
USA
Nevada, Elko Co., Proctor District, Silverzone Pass, Radar Hill

Goethite after Pyrite 4cm wide	© Rockpick Legend Co.

Goethite
USA
New Mexico, Eddy Co., Guadalupe Mountains




Goethite
USA
Ohio, Licking Co., Washington Township

Weathered concretion.




Goethite
USA
Utah, Garfield Co.

Moqui Balls (marbles) are goethite concretions.

Goethite 4cm wide	© Rockpick Legend Co.

Goethite 2.5cm wide	© Rockpick Legend Co.

Goethite
USA
Utah, Utah Co., Pelican Point Area

Goethite after Pyrite 5.9cm wide	© Rob Lavinsky

Goethite
USA
Wisconsin, Iron Co., Gogebic Range, Montreal Mine





3/10/2011



Edited 21 time(s). Last edit at 02/05/2012 11:19AM by Ralph Bottrill.

Dave,
I have been working on pseudomorphs and as you can imagine there are a lot of limonite and goethite images that have been uploaded to the image bank and actually I have used a few of the examples that you have shown above in those articles too. I have come to feel that many of the images are probably labeled hematite/goethite/limonite without anyone knowing what they are for sure. Most are probably limonite, that is a mixture of iron oxide minerals which include goethite and limonite. How confident are you that the images in your article here are really mostly pure goethite rather than limonite? Probably the Goethites from the Restormel mine, UK and the Crystal Peak area of Colorado and a couple of others? I often think what the uploaders or the dealers put on their labels and what gets passed on to the captions of our images is rather arbitrary with no grounding in real mineralogy. If you agree you might want to add in the introduction to the article a warning that many of these images may be limonite, a mixture of various iron oxide minerals and not real pure goethite. Perhaps in the captions of those that are know to be pure or nearly pure goethite, it could be emphasized that these are real goethite specimens/crystals. I plan to do this in the pseudomorph articles, at least to the best of my ability.

Rock Currier
Crystals not pistols.

"Limonite" is nowadays just a general field term for earthy iron oxides, not a species name. So, although theoretically "limonites" could be composed of lepidocrocite, hematite, maghemite, various hydrous iron oxides or oxy-hydroxides, and even powdery jarosite-group species, they are most commonly composed of goethite, so it's fairly safe to label them that way, especially when the streak is yellow-brown, they show no magnetism, and they have been kept dry for a long time (after which the less stable hydrated oxides mostly alter into goethite anyway).

I've had a lot of hard brown iron oxides x-rayed. Once in a while they turn out to be mainly hematite, like the christmas-tree shaped pseudos from Egypt, in spite of not having a very red streak, and once one locality turned out to be maghemite (I should have checked it with a magnet before wasting an XRD :( ) and another had a lot of jarosite in it. Never yet found a "limonite" that was lepidocrocite. Even if a sample turned out to be a goethite-bearing mixture, that wouldn't make a "goethite" label wrong.

[www.mindat.org]

Tordelrabano, Guadalajara, Castile-La Mancha, Spain

Here is another one to add: [www.mindat.org]

Dave,
Ive tweaked the formatting some to bring the Goethite article in line with the other articles here in best Minerals and added Alfredo's comment to the introduction.

Rock Currier
Crystals not pistols.

A small quarry near Freisen, Saarland, produced fine acicular crystals to over 2 cm (commonly < 1 cm, though). They occur in miarolitic cavities of a melaphyr basalt that are lined with smoky quartz, often together with chabazite. An undisclosed locality in Morocco (usually just described as "High Atlas Mts.") produced similar material, but never with chabazite.

[www.mindat.org]

Peter, Lets wait a bit and see if David wants to include them in the article at this time.

Rock Currier
Crystals not pistols.

Goethite was mined in NW Connecticut (Ore Hill in particular), western Massachusetts and adjacent New York state for almost 200 years. Many fine specimens are out there, but woefully few are pictured on mindat. I have several and will eventually photograph and post them, but it may be a few weeks...Also micro sprays of acicular golden-brown goethite crystals are known from East Haven, Connecticut. There are some photos up on the Cinque Quarry page: [www.mindat.org] and the High Street construction site: [www.mindat.org]

I basically don't have any problems if people want to edit any of my Best mineral articles.

Noted

Rock Currier
Crystals not pistols.

Interesting selection of specimens. I love the iron oxide minerals but
often find that sellers do not check their material even with simple streak
test to distinguish what is likely hematite from goethite. For that matter the
manganese oxides with their gray streak also come into play here. But then
as I think Alfredo points out it may take formal testing to be certain
regarding some specimens. There are also pieces that vary in
streak depending on what part of the rock you check.

Shifting topics here, does anyone know the explanation for the color bands in some
massive goethite specimens? It is common in the Great Lakes Iron Ranges of North
America. In the posted images under "Best Minerals" there are examples from Marquette Co,
Michigan and Wisconsin as well as the Minnesota specimen. Sometimes the
banding is very regular, almost like tree rings and assume the solution from which
crystals form must oscillate in composition. Has anyone seen fine banding in micro
xls of goethite such as occurs in some linear malachite xls?

Thanks for your thoughts,

George

George,
You question about the cause of color banding in massive goethite specimens would probably draw more attention in one of the other forums rather than here in the Best Minerals section, but you may get lucky and someone will respond to with the information you want. I don't know the answer, but I would expect that the difference would be found in the variable mineralogy of fine grained iron minerals that undoubtedly comprise the bulk of these specimens. Perhaps some grad student has made a study of them.

Rock Currier
Crystals not pistols.