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Trigonic Terminated Tourmaline?
  
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texasdigger




Joined: 22 Oct 2015
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PostPosted: Jun 21, 2017 18:53    Post subject: Trigonic Terminated Tourmaline?  

I'm looking at this termination and wondering a few things. I think the term trigonic applies but maybe only a mystical term...
1: Is it a modified termination?
2: Is it an etched termination?
3. Why the triangles?



Terminated1.jpg
 Mineral: Elbaite
 Locality:
Minas Gerais, Brazil
 Dimensions: 2.4 x 1.5 cm
 Description:
 Viewed:  1160 Time(s)

Terminated1.jpg



Terminated2.jpg
 Mineral: Elbaite
 Locality:
Minas Gerais, Brazil
 Dimensions: 2.4 x 1.5 cm
 Description:
 Viewed:  1153 Time(s)

Terminated2.jpg


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Peter Lemkin




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PostPosted: Jun 21, 2017 23:21    Post subject: Re: Trigonic Terminated Tourmaline?  

I'm not an expert on this, but is sure looks etched to me. Nice etch figures, at that!
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lluis




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PostPosted: Jun 22, 2017 02:10    Post subject: Re: Trigonic Terminated Tourmaline?  

Hi, Texasdigger

Well, tourmaline is trigonal
https://www.mindat.org/min-4003.html

So, triangles could be just the result of etching or just a consequence of crystal growing under determinate circumstances... I think in your case more second thing.

Nothing mystic. Just chemistry and crystallography.

And as Peter says, a nice piece, at least to my eyes!

With best wishes

Lluís
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