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Roger Warin
Joined: 23 Jan 2013
Posts: 1176
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Posted: May 18, 2022 13:56 Post subject: Calcite in Malkhan elbaite |
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Hello,
Here is a specimen from Malkhan, with the elbaite as a signature.
Crystals with a spindle habit are calcite.
I didn't know this deposit had any.
Is it correct ?
Don't tell me to put a drop of muriatic acid...
Mineral: | Calcite |
Locality: | Malkhan (Malchan), Krasnyi Chikoy, Zabaykalsky Krai, Russia | |
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Dimensions: | cabinet size |
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5125 Time(s) |
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Jesse Fisher
Joined: 18 Mar 2009
Posts: 629
Location: San Francisco
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Posted: May 18, 2022 14:46 Post subject: Re: Calcite in Malkhan elbaite |
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I have an elbaite from Malkhan that has associated stilbite. Late stage zeolites including stilbite have been reported from these pegmatites, so I would not be surprised to see late stage calcite. Both have been found in the Himalaya pegmatite, San Diego County, California.
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Roger Warin
Joined: 23 Jan 2013
Posts: 1176
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Posted: May 19, 2022 00:26 Post subject: Re: Calcite in Malkhan elbaite |
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Hello Jesse,
Your answer sounds pretty good to me. I doubted those sheafing crystals were calcite. I will do the hydrogen chloride test.
The names of the minerals were given by the dealer.
Thank you very match.
Roger.
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Gagat Minerals
Joined: 08 Nov 2017
Posts: 43
Location: Greater London
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Posted: May 19, 2022 02:07 Post subject: Re: Calcite in Malkhan elbaite |
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I don't know what it is, but the shape of the crystals resembles some forms of heulandite
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Edelmin
Joined: 24 Mar 2009
Posts: 43
Location: Salamanca
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Posted: May 19, 2022 03:57 Post subject: Re: Calcite in Malkhan elbaite |
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Hello,
I think those crystals may be just albite. They resemble some of the albite associated to aquamarines and garnets from some localities at the Shigar Valley, Pakistan. Depending on the orientation of the crystals they show a rhombic shape similar in some way to the crystals of your specimen.
Best regards,
Felix
_________________ Felix G. Garcia
Edelmin |
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4896
Location: Barcelona
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Posted: May 19, 2022 04:13 Post subject: Re: Calcite in Malkhan elbaite |
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Edelmin wrote: |
I think those crystals may be just albite. They resemble some of the albite associated to aquamarines and garnets from some localities at the Shigar Valley, Pakistan. Depending on the orientation of the crystals they show a rhombic shape similar in some way to the crystals of your specimen.
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I agree with Felix
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Jesse Fisher
Joined: 18 Mar 2009
Posts: 629
Location: San Francisco
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Posted: May 19, 2022 09:59 Post subject: Re: Calcite in Malkhan elbaite |
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I have seen numerous specimens of albite from the Shigar Valley pegmatites with the habit that Felix describes. However, I have never seen anything but the cleavelandite habit on specimens from Malkhan. A drop of HCl, and a hardness test (if necessary) should tell the difference between albite, calcite or a zeolite.
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Josele
Joined: 10 Apr 2012
Posts: 407
Location: Tarifa, Spain
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Posted: May 19, 2022 12:23 Post subject: Re: Calcite in Malkhan elbaite |
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Another vote for plagioclase.
Although uncommon, calcite in pegmatite can occur indeed.
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Roger Warin
Joined: 23 Jan 2013
Posts: 1176
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Posted: May 19, 2022 14:00 Post subject: Re: Calcite in Malkhan elbaite |
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Hello everyone, Jesse,
Sorry, HCl has no action on this mineral.
It is difficult to do tests for hardness, etc., given the texture of the sheaves.
I nevertheless made macrophotos with the binocular.
Fortunately, I could put the Eifel Tower under my bino.
The photos are difficult to take given the lack of “relief” of the views.
But Photoshop and Helicon allow me to present a first view to you.
It seems that the answer in favor of a form of albite is the most probable, and even from a geological point of view. But the debate continues.
The second photo shows free growths present on the sheaf.
Thanks for trying to solve my question.
Roger.
PS: I bought this specimen because I like to illustrate the geological context which sees the birth of these minerals, of which we often only have an isolated prism, such as elbaites for example.
Mineral: | Albite ? |
Locality: | Malkhan (Malchan), Krasnyi Chikoy, Zabaykalsky Krai, Russia | |
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4896 Time(s) |
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Mineral: | Albite ? |
Locality: | Malkhan (Malchan), Krasnyi Chikoy, Zabaykalsky Krai, Russia | |
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Description: |
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4904 Time(s) |
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