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 Post subject: Inclusions in Quartz: GILALITE
PostPosted: Mon Mar 08, 2010 11:27 pm 
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Here are a couple pics of gilalite in quartz I picked up in Tucson.
The material is found in the Paraiba district of Brazil.
The first is typically what one sees in this sort of specimen, clear quartz with floating discs of gilalite, often referred to as Medusa Quartz or hyperbolized as "Paraiba Quartz" . Taken with fiber optic light, not dark field:
Image

When these discs are viewed sideways, you can see where the name "medusa" quartz comes from:
Image

Here is a specimen of quartz with fibrous gilalite disseminated throughout the entire specimen:
Also shot with fiber optic light.
Image
Image


Last edited by Barbra Voltaire on Thu Mar 11, 2010 10:46 pm, edited 4 times in total.

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PostPosted: Mon Mar 08, 2010 11:35 pm 
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Think I'll drool over this thread for a while...Miss Barb, kick me off after 36 hours of staring at it please...

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PostPosted: Tue Mar 09, 2010 2:34 am 
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Somebody got her digital camera stuck onto her Zeiss scope :D
Nice shots Barbra!


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PostPosted: Tue Mar 09, 2010 3:15 am 
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Dang..some nice pics and descrips. very impressive...as Astrid Alauda would say "there are worlds in opals...err..inclusions"

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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sat Dec 11, 2010 1:57 pm 
More Gilalite and other inclusions:

1. Cabbed quartz at approx x12. Shape and size prevent safe use of stone clip, so this is sitting on the slightly opened light-well iris.
Attachment:
Quartz + Gilalite 1-03b.JPG
Quartz + Gilalite 1-03b.JPG [ 73.1 KiB | Viewed 4396 times ]


2. Approx x30
Attachment:
Quartz + Gilalite 1-05b.JPG
Quartz + Gilalite 1-05b.JPG [ 105.29 KiB | Viewed 4396 times ]


3. Single Gilalite inclusion showing acicular habit. x65
Attachment:
Quartz + Gilalite 1-06a.JPG
Quartz + Gilalite 1-06a.JPG [ 76.57 KiB | Viewed 4396 times ]


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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sat Dec 11, 2010 2:49 pm 
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Niiice Gilaite both of you, glad to see you posting those nice images Barbra.

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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sat Dec 11, 2010 3:47 pm 
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Those are really neat images Barbra. I always wonder how these minerals can form as they do, just floating on the middle of something with a completely different chemistry and structure. It's really kind of magical.

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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sat Dec 11, 2010 3:55 pm 
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Cool shots Barbra and Owen!! :D i bet i know from who those specimen comes Barbra..... :wink:
ciao
albé

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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sat Dec 11, 2010 5:39 pm 
michael_e wrote:
Those are really neat images Barbra. I always wonder how these minerals can form as they do, just floating on the middle of something with a completely different chemistry and structure. It's really kind of magical.


There's an article on the net http://www.yourgemologist.com/ISGForums ... php?t=6173, that says that gilalite in quartz is a faked composition of quartz and glasses, clear and blue. It explains how to do this and links Barbra's pics on this GO thread as an 'illustration' of it's proposition. I thought that some pics that show clearly the acicular habit of the gilalite at stages of magnification sufficient to show no manipulation might sufficiently discredit that outside post and its implications. Don't think you can fake 'acicular' by blobbing molten blue glass :)

Admin Note: These folks above have rethought their position after new evidence was presented to them. They have retracted their posts and articles.


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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sun Dec 12, 2010 11:40 am 
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This woman PMd me directly a while back insisting that I never ran any tests on my material and it was actually glass.

I ran tests to verify and the specimens were indeed quartz. They are.
G&G has articles on gilalite in qtz. My specimens were also purchased from Marco Campos Venuti.

Ms. Gringa is misinformed.....yet again. I doubt she ever physically tested the material; her conclusions were speculative based on misinformation and misinterpretation of photos. You will notice that there are NO verified examples of the faked up glass she speculates exist.

Other posters have corrected the misinformation on the link Kerensky provided.


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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sun Dec 12, 2010 12:39 pm 
Barbra,
For some reason I can't see the third pic you posted. Broken link or....?

Yes, I also did the usual tests for doublet and came up with nothing untoward from my sample. Though I have not posted them here, in my records there is also photo-evidence of the following in the same stone, in addition to examples of a very pronounced acicular habit:
- Medusa formation.
- Scattering of the gilalite in depth, sufficient to make very unlikely any laying down of fake (or real) material on a prepared quartz base prior to sealing in under glass.
- Similar scattering in depth of minute inclusions of one or more other types, including (I think) two phase inclusions.

Being suspicious of something new is one thing - but best to zip the mouth until one has some test results, no?

Those 'other inclusions' invite further exploration when I get around to it. They are small enough both to warrant some observation at > x150 mag and, insh'Allah, for me not to be too disadvantaged by not yet having upgraded my camera so I can use image stacking software :)


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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sun Dec 12, 2010 12:48 pm 
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Quote:
Barbra,
For some reason I can't see the third pic you posted. Broken link or....?
Fixed. :D


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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Sun Dec 12, 2010 1:08 pm 
Barbra Voltaire wrote:
Quote:
Barbra,
For some reason I can't see the third pic you posted. Broken link or....?
Fixed. :D

Mmmm! Nice! Thanks :D


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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Wed Dec 22, 2010 8:20 am 
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Ok, I must have missed this original post way back...

but the question now is - where can I get a piece of this??? Rough would be preferrable, otherwise a finished cab.

Gorgeous stuff!

-Allan

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 Post subject: Re: Inclusions in Quartz: GILALITE
PostPosted: Wed Dec 22, 2010 11:39 am 
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Going to Tucson?
That's where I got mine.
It was purchased from Marco Campos Venuti.
He is set up in a small room FILLED with bins of the most interesting inclusions you will ever see in one spot.
:D


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