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A general guide for using the Forum with some rules and tips
Favourite Quartzes?
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Enrique Llorens




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PostPosted: Sep 09, 2016 09:42    Post subject: Re: Favourite Quartzes?  

Quartz from Peru


DSC_0637.JPG
 Mineral: Quartz
 Locality:
Mundo Nuevo mining area, Mundo Nuevo, Huamachuco, Sánchez Carrión Province, La Libertad Department, Peru
 Dimensions: 11cm
 Description:
Labor Teo
 Viewed:  4744 Time(s)

DSC_0637.JPG


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crosstimber
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PostPosted: Sep 09, 2016 10:34    Post subject: Re: Favourite Quartzes?  

This tiny little Quartz var. Herkimer diamond has always been one of my favorites because of the clarity and unusual morphology. I collected this one back in 1962.


Quartz - Middleville, Herkimer Co., New York.jpg
 Mineral: Quartz
 Locality:
Middleville, Town of Newport, Herkimer County, New York, USA
 Dimensions: 8 mm x 10 mm
 Description:
 Viewed:  4725 Time(s)

Quartz - Middleville, Herkimer Co., New York.jpg


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geofossile




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PostPosted: Sep 30, 2016 01:54    Post subject: Re: Favourite Quartzes?  

Quartz with Muscovite (variety fuchsite) from Itremo, Madagascar.


DSC_0063.JPG
 Mineral: Quartz with Muscovite (variety fuchsite) inclusions
 Locality:
Ihovitra, Itremo Massif, Itremo, Ambatofinandrahana District, Amoron'i Mania Region, Fianarantsoa Province, Madagascar
 Description:
 Viewed:  4604 Time(s)

DSC_0063.JPG


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Jordi Fabre
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PostPosted: Sep 30, 2016 02:47    Post subject: Re: Favourite Quartzes?  

geofossile wrote:
Quartz with Muscovite (variety fuchsite) from Itremo, Madagascar.

Size please?
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Bergur_E_Sigurdarson




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PostPosted: Dec 25, 2017 08:04    Post subject: Re: Favourite Quartzes?  

My favourite quartz, with paralell secondary growths.

Main crystal : H 85mm x W 27mm x D 25mm

Bought in the village of Muzo from local vendor.

(Can anyone tell me what this sort of growth would be called?)

(After looking for variations of quartz growths, the closest I could find was called "cactus", but those seemed to grow outwards from the main original crystal, not paralell like in this specimen.
Also, after reading another topic here on the forum, where photos of epitaxy were posted.... would this be an auto-epitaxy ?
(according to Pete Richards definition, if I understood correctly... but not according to John S. White (a discussion I enjoyed))) :-)



quartz-faceted.jpg
 Mineral: Quartz
 Locality:
Muzo mining district, Western Emerald Belt, Boyacá Department, Colombia
 Dimensions: H 8.5cm x W 4.6cm x D 3.7cm
 Description:
 Viewed:  3300 Time(s)

quartz-faceted.jpg



quartz-faceted-end.jpg
 Mineral: Quartz
 Locality:
Muzo mining district, Western Emerald Belt, Boyacá Department, Colombia
 Dimensions: H 8.5cm x W 4.6cm x D 3.7cm
 Description:
Bottom view, showing opaque layer between initial and secondary growths.
 Viewed:  3306 Time(s)

quartz-faceted-end.jpg


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vic rzonca




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PostPosted: Dec 25, 2017 10:30    Post subject: Re: Favourite Quartzes?  

This is from the book by Harold L. Dibble, Quartz." Cathedral Quartz. One of the most common of these types is known as Cathedral quartz. These are crystals with the axes of the secondary crystals parallel to those of the main crystal. These clusters vaguely resemble smaller spires or buttresses around the main spire of a cathedral." More of a descriptive term than a scientific one. I guess everything has to be called something.
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Tobi




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PostPosted: Apr 08, 2018 13:09    Post subject: Re: Favourite Quartzes  

Definitely two of my favourites:


ArkQUAR.JPG
 Mineral: Quartz (variety rock crystal)
 Locality:
Mount Ida, Montgomery County, Arkansas, USA
 Dimensions: Specimen height 20,5 cm
 Description:
 Viewed:  2577 Time(s)

ArkQUAR.JPG



GaliSMOKY.JPG
 Mineral: Quartz (variety smoky quartz)
 Locality:
Galiléia, Vale do Rio Doce, Minas Gerais, Brazil
 Dimensions: Specimen height 14 cm
 Description:
 Viewed:  2574 Time(s)

GaliSMOKY.JPG


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Heimo Hellwig




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PostPosted: Jun 03, 2018 11:45    Post subject: Re: Favourite Quartzes?  

Quartz from Goboboseb. Saw this specimen when visiting an elderly gentleman in the retirement village. He allowed me to photograph and post it on the Forum. Nicest local Quartz I have come across.


DSCF2103.JPG
 Mineral: Quartz
 Locality:
Goboboseb Mountains, Brandberg area, Erongo Region, Namibia
 Dimensions: 112mm x 105mm x 68mm
 Description:
 Viewed:  2207 Time(s)

DSCF2103.JPG



DSCF2104.JPG
 Mineral: Quartz
 Locality:
Goboboseb Mountains, Brandberg area, Erongo Region, Namibia
 Dimensions: 112mm x 105mm x 68mm
 Description:
Same as above.
 Viewed:  2207 Time(s)

DSCF2104.JPG


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Bob Harman




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PostPosted: Jun 05, 2018 09:54    Post subject: Re: Favourite Quartzes?  

Groups of tiny water clear quartz crystals showing free form growths adjacent to a calcite crystal. Self collected about 10 years ago.


fullsizeoutput_29ad.jpeg
 Mineral: QUARTZ
 Locality:
Monroe County, Indiana, USA
 Dimensions: The individual crystals are 1 - 3mm. The whole area is about 2.5 cm
 Description:
Self collected about 10 years ago.
 Viewed:  2101 Time(s)

fullsizeoutput_29ad.jpeg



fullsizeoutput_29ae.jpeg
 Mineral: Quartz
 Locality:
Monroe County, Indiana, USA
 Dimensions: The individual crystals are 1 - 3mm. The whole area is about 2.5 cm
 Description:
 Viewed:  2104 Time(s)

fullsizeoutput_29ae.jpeg


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Tobi




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PostPosted: Jun 10, 2018 00:40    Post subject: Re: Favourite Quartzes?  

Heimo Hellwig wrote:
Quartz from Goboboseb. Saw this specimen when visiting an elderly gentleman in the retirement village. He allowed me to photograph and post it on the Forum. Nicest local Quartz I have come across.

Locality: Goboboseb Mountains, Brandberg area, Erongo Region, Namibia
Dimensions: 112mm x 105mm x 68mm
This is really one of the most fascinating Brandberg quartzes I have ever seen, Heimo, thanks for showing!
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James
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PostPosted: Jun 13, 2018 14:12    Post subject: Re: Favourite Quartzes?  

This seems to be an open Gwindel from Spain. We found this single specimen in 2007 in a small outcrop next to a vein of quartz. There were other quartz crystals but none like this. The crystal faces are parallel but there is a slight twist between the two crystals, which I only noticed today.

See what you think? Is it a Gwindel or just two almost totally parallel crystals

The locality where it was found is mentioned in Volumen VIII, Cuarzo y otros minerales de silice, Miguel Calvo Rebollar, p 243, top of the page where it says "La Presa".



Y93 a.JPG
 Mineral: Quartz
 Locality:
"The Dam", Aulencia River, Colmenarejo, Comarca Cuenca del Guadarrama, Madrid, Community of Madrid, Spain
 Dimensions: 53 x 25 x 15 mm
 Description:
 Viewed:  1794 Time(s)

Y93 a.JPG



Y93 c.JPG
 Mineral: Quartz
 Locality:
"The Dam", Aulencia River, Colmenarejo, Comarca Cuenca del Guadarrama, Madrid, Community of Madrid, Spain
 Dimensions: 53 x 25 x 15 mm
 Description:
You can see the twist in this one
 Viewed:  1809 Time(s)

Y93 c.JPG



Y93 b.JPG
 Mineral: Quartz
 Locality:
"The Dam", Aulencia River, Colmenarejo, Comarca Cuenca del Guadarrama, Madrid, Community of Madrid, Spain
 Dimensions: 53 x 25 x 15 mm
 Description:
And the parallel faces in this one.
 Viewed:  1791 Time(s)

Y93 b.JPG


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Bob Morgan




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PostPosted: Jun 13, 2018 20:03    Post subject: Re: Favourite Quartzes?  

Does this specimen have several Japan Law twins?
http://www.mineral-forum.com/message-board/download.php?id=72376

It resembles one that Jaroslav Hyrsl found with many twins.
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Bob Morgan




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PostPosted: Jun 13, 2018 20:14    Post subject: Re: Favourite Quartzes?  

The above post was in reference to Enrique LLorenz's Peruvian Specimen at the first of this thread.
http://www.mineral-forum.com/message-board/download.php?id=72376

As to the question about whether the double crystal immediately above is a Gwindel, I don't think so. The attachment would be on a prism face.
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James
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PostPosted: Jun 14, 2018 08:13    Post subject: Re: Favourite Quartzes?  

Bob

The attachment is a prism face - the two are attached to each other by their prism faces. That is why it had me confused - every face in each crystal has a parallel face in the other one, but there is about a 4 degree twist between them. So it looks like two totally parallel crystsls with a twist (clockwise) between them.
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Bob Morgan




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PostPosted: Jun 14, 2018 08:45    Post subject: Re: Favourite Quartzes?  

I can see your point and agree the divergence is reasonable as a gwindel. I was referring to the attachment to the matrix, which is usually along a prism face of one crystal. Still...?
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Josele




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PostPosted: Jun 14, 2018 15:47    Post subject: Re: Favourite Quartzes?  

Bob Morgan wrote:
... As to the question about whether the double crystal immediately above is a Gwindel, I don't think so. The attachment would be on a prism face.
I think is not a gwindel precisely because the attachment IS on prism faces. Should be on a "a" axis, which cross an edge between two prism faces. Gwindel rotation occurs along this "a" axis and the result is a wide prism face with steps that are a progresively rotated. Is really better explained in The Quartz Bible.

Bob Morgan wrote:
Does this specimen have several Japan Law twins? http://www.mineral-forum.com/message-board/download.php?id=72376 ...
Japan law twin has the contact plane almost on the bisector of "c" and a "a" axis, so that "c" axis of both crystals cross in one point conforming an almost right angle and leaving two of the prism faces of one individual parallel to two prism faces of the other, which I'm not able to observe in the picture. Again, is better explained in The Quartz Bible.

Bob Morgan wrote:
I can see your point and agree the divergence is reasonable as a gwindel. I was referring to the attachment to the matrix, which is usually along a prism face of one crystal. Still...?
The attachment to matrix is irrelevant, I think.
Anyway, I don't see any matrix in James's quartz, seems to be an almost floater piece.
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Bob Morgan




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PostPosted: Jun 14, 2018 17:41    Post subject: Re: Favourite Quartzes?  

I agree it's not a gwindel, even though it looks like there might be an a axis alignment at some spot. Very open gwindels can have some notched separation, but this would be too extreme.
There does appear to be a point of attachment on one crysrtal's pyramid, but gwindels grow out of the matrix along the a axis.

As to the Peruvian quartz, the possible twinning would be small deposition crystals on larger ones. That is very common from that locality, but can't be discerned from the photo.
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Josele




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PostPosted: Jun 14, 2018 18:00    Post subject: Re: Favourite Quartzes?  

Bob, you are right, many characteristics are not clearly visible in a photo, that's why I like to say "I think that ..."

Is true that high end and fine gwindel specimens usually show both terminations free of contact, with "c" axis more or less parallel to matrix surface, but there are also many samples that seem to be attached to matrix at terminations, with "c" axis penetrating into matrix, as can be seen in Gwindel Mindat Gallery
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Amir Akhavan




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PostPosted: Jun 15, 2018 05:26    Post subject: Re: Favourite Quartzes?  

Sorry to interrupt ;-) but I'd like to point out that a gwindel is not a composite or aggregate.
It's not made of stacked crystals and it has nothing to do with parallel growth.
Each gwindel started as a s i n g l e c r y s t a l that is elongated along and twisted around an a-axis.
That many gwindels and in particular open gwindels show sutures and that their tips fan out is a secondary effect of being overgrown by a layer of macromosaic quartz.
Amir

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