[Rockhounds] ID help

[Axel Emmermann]

Jim, 

People like you make it worthwhile for people like us....
Carry on!Please...

Axel

Axel Emmermann
European Regional Vice President of the
Fluorescent Mineral Society
<http://www.uvminerals.org/>
=========================
Mineralogische Kring Antwerpen/Antwerp Mineralogical Society
<http://www.minerant.org/index.html>
Werkgroepleider/Workgroup leader: Fluorescerende mineralen/Fluorescent
minerals
Technische Realisaties/Engineering
My website: http://users.telenet.be/axel.emmerman/FiatLux/Index.php
 
 
> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com
[mailto:rockhounds-bounces at lists.drizzle.com]
> Namens Lawrence Rush
> Verzonden: dinsdag 30 juni 2009 15:00
> Aan: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
> Onderwerp: Re: [Rockhounds] ID help
> 
> A definitive answer on my Pakistani unknown! Jim Murowchick was kind
enough
> to do the tests; here are his results.....
> 
> Larry-
>     I received your sample today, and there was more than enough to do XRD
> and optical work.  The powder XRD indicated orthoclase and
> tremolite/actinolite.  The XRD patterns for tremolite and actinolite are
> virtually identical, so on to the optical microscopy.  The sample had
> acicular, white crystals outside of the orthoclase crystals, and the
> orthoclase has abundant inclusions of colorless (under the microscope)
> needles. Since the XRD indicated tremolite or actinolite, and the crystals
> are colorless under the scope, but the specimen has a greenish color
> macroscopically, I think the needles are probably a magnesium-rich
> actinolite or at least a ferroan tremolite.  It's interesting that on
> Mindat, "chlorite" is a common associate of the adularia, and the green
> color of some of the specimens is attributed to chlorite.  I didn't see
any
> mention of actinolite, though with any of the green specimens.  I don't
know
> if that's just because chlorite is associated with adularia in the Alps,
or
> if some of the "chlorite" was misidentified and might actually be
actinolite
> in some cases.
> 
>     I ran a chip of the orthoclase on a spindle stage to get an optic
axial
> angle (2V) of 69.32°.  The mineral is biaxial (-), with n(alpha)=1.518,
> n(beta)=n(gamma)=1.522 by immersion in refractive index oils.  These are
> perfect matches for orthoclase.
> 
> Conclusion:  the crystals are orthoclase, variety adularia pigmented with
> light green tremolite/actinolite.  That was fun!
> 
> Cheers,
> Jim
> 
> ======================================================
> 
> Many thanks to all who helped! Especially Jeff Fast, Petes Modreski and
> Richards, and Axel Emmermann, who were right on!
> 
> (And I apologize for leading others astray with my erroneous hardness
> test!!)
> 
> Rock on!!
> Larry Rush
> 
> 
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> 
> --
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