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BHmineral
Joined: 14 Dec 2012
Posts: 29
Location: Diamantina -MG (Brasil)
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Posted: Apr 08, 2013 10:16 Post subject: Sphaerocobaltite |
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Hi,
I'm in doubt about the question: are Sphaerocobaltite and cobaltocalcite the same mineral or are there differences between these minerals?
Thank you
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GneissWare
Joined: 07 Mar 2008
Posts: 1287
Location: California
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Posted: Apr 08, 2013 10:48 Post subject: Re: Sphaerocobaltite |
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BHmineral wrote: | Hi,
I'm in doubt about the question: are Sphaerocobaltite and cobaltocalcite the same mineral or are there differences between these minerals?
Thank you |
No Ca in Sphaerocobaltite.
Sphaerocobaltite is CoCO3
cobaltocalcite is (Ca,Co)CO3
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
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Location: Barcelona
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BHmineral
Joined: 14 Dec 2012
Posts: 29
Location: Diamantina -MG (Brasil)
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Posted: Apr 08, 2013 15:06 Post subject: Re: Sphaerocobaltite |
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Ok.
Thank you very much.
Eduardo
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Peter Megaw
Site Admin
Joined: 13 Jan 2007
Posts: 963
Location: Tucson, Arizona
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Posted: Apr 08, 2013 15:47 Post subject: Re: Sphaerocobaltite |
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A related subject is the common mislabeling of calcite that is pink because of manganese as either sphaerocobaltite or cobaltian/cobaltoan calcite (or even cobalt-rich calcite).
This mislabeling is widely true of the manganese bearing calcites from the Aranzazu Mine at Concepcion del Oro, Zacatecas, Mexico. These have been analyzed and they contain NO cobalt at all, while being high in manganese. This is beautifully displayed under SWUV...they fluoresce bright red-orange
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Calcite (manganese-rich) Aranzazu Mine, Concepcion del Oro, Zacatecas, Mexico 6 cm Many similar pieces are incorrectly labled sphaerocobaltite or cobaltian calcite Peter Megaw Specimen, Jeff Scovil photograph |
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_________________ Siempre Adelante! |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1176
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Posted: Apr 08, 2013 16:14 Post subject: Re: Sphaerocobaltite |
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Cobaltoan calcite contains not more than 1% of cobalt. As said Jordi, it is only calcite, not another mineral species.
This small amount of cobalt does give a beautiful purple color to this single crystal whose ternary termination is an obtuse rhombohedron {01.2}.
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Calcite-(Co) Filon Aghbar, Bou Azzer, Maroc |
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Roger Warin
Joined: 23 Jan 2013
Posts: 1176
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Posted: Apr 10, 2013 10:58 Post subject: Re: Sphaerocobaltite |
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Spherocobaltite, Kakanda (Katanga).
Here is a specimen of spherocobaltite, CoCO3.
Kakanda is a group of three mines (North, East and South) and two hills, Disele and Fungurume.
Kakanda is located just west of Likasi in Central Copper Crescent.
In the Mindat.org page, this mineral exists as spherocobaltite.
In Fleisher’s Glossary, it’s discredited. Why? Is there no mineral whose composition is CoCO3? Wow, very odd…
The crystal habit is special. It looks like rosettes with petals are saddles shaped (as dolomite).
The purple color is very dark, difficult to shoot.
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Spherocobaltite Kakanda, Katanga DRCongo 4 cm wide |
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Spherocobaltite Kakanda, Katanga DRCongo |
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Spherocobaltite Kakanda, Katanga DRCongo |
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