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Scott LaBorde
Joined: 14 Dec 2009
Posts: 104
Location: North Carolina
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Posted: Feb 17, 2010 00:30 Post subject: Re: Tessin habit quartz |
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Here are the two crystals in the previous post, after removing them from acid.
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This was the left most crystal in the previous post. 8 x 3 x 3 cm |
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24553 Time(s) |
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This was the crystal on the right side of my previous post. This was the opposite side of the crystal shown in the picture. I decided to display this side because to me it was much more interesting. 10.5 x 6 x 3 cm |
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_________________ Scott LaBorde |
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Scott LaBorde
Joined: 14 Dec 2009
Posts: 104
Location: North Carolina
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Posted: Feb 21, 2010 22:22 Post subject: Re: Tessin habit quartz |
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I found two more this weekend.
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Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 828
Location: Northeast Ohio
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Posted: Jun 17, 2010 19:54 Post subject: Re: Tessin habit quartz |
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It's been about four months since the last post to this thread. In the meantime, i've had a chance to collect in North Carolina with Scott Laborde, though I did not find any crystals as spectacular as those he posted. He sent me home with one of his Tessin habit quartz crystals, and I finally got around to measuring it on the goniometer. The attached drawings capture the general habit, but not details/distortions due to the specific growth history
For those who can deal with Miller indices, the main faces that distinguish this habit from the typical prismatic habit belong to the steep rhombohedra {30-31} and {03-31}. An even steeper rhombohedron is present as a couple of faces.
Most interesting is the beveling face labeled 21-31. That is a label of convenience, and it correctly depicts these modifying faces as being basically parallel-edged between the two steep rhombohedra. The goniometric measurements only revealed {11-21} as a measurable face. These beveling faces are diagonally striated and are obviously an intimate combination of at least two forms, probably {51-61} in addition to {11-21}. In other terminology, these faces are an intermediate form between the s and x faces. However, these are not true faces, since they are composed entirely of little stripes of faces of different orientations.
Hopefully some will be interested in these geometric details of one example of the Tessin habit of quartz!
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24393 Time(s) |
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_________________ Collecting and studying crystals with interesting habits, twinning, and epitaxy |
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Scott LaBorde
Joined: 14 Dec 2009
Posts: 104
Location: North Carolina
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Posted: Jun 22, 2010 23:23 Post subject: Re: Tessin habit quartz |
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I found this crystal this past Sunday in an alpine type fissure. The bottom of it looks as though it were either healing into a biterminated crystal or some kind of etching. To read the whole story behind it: https://www.rockhoundlounge.com/june13and20_2010.shtml
(link normalized by FMF)
Scott
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5 x 2.5 cm Tessin habit quartz Cary, NC |
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24269 Time(s) |
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Scott LaBorde
Joined: 14 Dec 2009
Posts: 104
Location: North Carolina
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James Catmur
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Joined: 14 Sep 2006
Posts: 1349
Location: Cambridge
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Scott LaBorde
Joined: 14 Dec 2009
Posts: 104
Location: North Carolina
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Posted: Jul 10, 2014 21:48 Post subject: Re: Tessin habit quartz |
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In an attempt to resurrect this thread, I want to display a few fine examples demonstrating the peculiar "s" face's or combination of "s" and "x" faces that bevel the transition between two "m" (prism) faces on some tessin habit quartz crystals.
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Quartz - Tessin Habit Raleigh, NC right handed |
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Quartz - Tessin Habit Raleigh, NC right handed |
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Quartz - Tessin Habit Raleigh, NC right handed |
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Quartz - Tessin Habit Raleigh, NC right handed |
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Quartz - Tessin Habit Raleigh, NC right handed |
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Quartz - Tessin Habit, included rutile Raleigh, NC right handed |
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Quartz - Tessin Habit Raleigh, NC right handed |
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Quartz - Tessin Habit Raleigh, NC left handed |
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Quartz - Tessin Habit Raleigh, NC left handed |
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Quartz - Tessin Habit Raleigh, NC A magnification of z33 above. |
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Scott LaBorde
Joined: 14 Dec 2009
Posts: 104
Location: North Carolina
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Posted: Jul 10, 2014 22:55 Post subject: Re: Tessin habit quartz |
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A magnification of z31 above.
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Quartz - Tessin Habit Raleigh, NC
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Rizwan
Joined: 22 Oct 2012
Posts: 14
Location: Peshawar
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Posted: Jul 11, 2014 20:33 Post subject: Re: Tessin habit quartz |
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This is an interesting topic for me. As a learner, I just wanted to share a piece and would like to see if this counts as similar species..
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Double terminated Smoky Quartz with schorl Inclusions Northern Area of Pakistan 125x31x27 mm |
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Double terminated Smoky Quartz with schorl Inclusions Northern Area of Pakistan 125x31x27 mm |
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Rizwan |
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Scott LaBorde
Joined: 14 Dec 2009
Posts: 104
Location: North Carolina
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Posted: Jul 14, 2014 12:28 Post subject: Re: Tessin habit quartz |
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The tessin habit feature -- a narrowing of the hexagonal prism toward the ends (terminations) is certainly in your crystal. You could call it tessin habit although it is transitional (mixed) with normal habit as well. In other words there is not a smooth progression or narrowing toward the tip as found in my previous photographs. But it's all relative. A microscopic view of even the smoothest text book tessin habit crystal would show a less than perfect progression or narrowing. In fact all tessin's may be transitional in some sense, they just step or narrow inward in a much more regular and even interval
Please view Amir C. Akhavan's excellent website for what I consider the best online resource for quartz, "The Quartz Page".
Here he describes the various quartz habits:
https://www.quartzpage.de/crs_habits.html
(link normalized by FMF)
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Rizwan
Joined: 22 Oct 2012
Posts: 14
Location: Peshawar
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Posted: Jul 16, 2014 10:35 Post subject: Re: Tessin habit quartz |
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Thank you Scott, that is very helpful.
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Rizwan |
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Clifford Trebilcock
Joined: 14 Mar 2014
Posts: 12
Location: Phippsburg, Maine
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Posted: Sep 12, 2014 15:36 Post subject: Re: Tessin habit quartz |
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Hi Scott,
Very interesting discussion about Tessin habit Quartz. When I saw Pete Richard's Drawing of a double terminated Tessin Quartz Crystal, it reminded me of an unusual shaped Quartz crystal I had many years ago in New Hampshire and had put away in a draw. So I decided to post some photos of the crystal. I collected it back in 1988 from a large pocket of smoky Quartz that had many crystals that had broken been broken and later continued to grow many unusual faces.
Mineral: | Quartz |
Dimensions: | 8.0 x 2.5 X 1.5 CM |
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Double terminated Tessin Habit Quartz Crystal |
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Mineral: | Quartz |
Dimensions: | 8.0 x 2.5 X 1.5 CM |
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19857 Time(s) |
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Mineral: | Quartz |
Dimensions: | 8.0 x 2.5 X 1.5 CM |
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19883 Time(s) |
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Dimensions: | 8.0 x 2.5 X 1.5 CM |
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19853 Time(s) |
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Mineral: | Quartz |
Dimensions: | 8.0 x 2.5 X 1.5 CM |
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19848 Time(s) |
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Josele
Joined: 10 Apr 2012
Posts: 407
Location: Tarifa, Spain
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Posted: Sep 13, 2014 06:05 Post subject: Re: Tessin habit quartz |
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Let me add some photos that I took in a mineral shop in Pokhara, Nepal, with a well developed Tessin habit, sometimes in combination with normal prism habit.
Tessin habit is the norm in Ganesh Himal quartz specimens.
To me, is very difficult see if these Tessin habits are due to {201}, {301}, {401} or {501} faces, or a combination of them, perhaps also including small steps of {100} prism faces.
Anyway specimens with Tessin habit are really lovely.
Mineral: | Quartz |
Locality: | Ganesh Himal, Dhading District, Bagmati Pradesh, Nepal | |
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Dimensions: | 35 x 12 x 10 cm |
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Big quartz with Tessin habit prism and Dauphiné habit rhombohedral face tip. Photo taken in Himalayan Gems and Minerals, Pokhara, Nepal, by courtesy of Ms. Manandhar. |
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19760 Time(s) |
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Mineral: | Quartz |
Locality: | Ganesh Himal, Dhading District, Bagmati Pradesh, Nepal | |
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Dimensions: | Height: 38 cm |
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Big quartz pair with some chlorite arborescences attached on the side. Photo taken in Himalayan Gems and Minerals, Pokhara, Nepal, by courtesy of Ms. Manandhar. |
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19763 Time(s) |
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Mineral: | Quartz |
Locality: | Ganesh Himal, Dhading District, Bagmati Pradesh, Nepal | |
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Dimensions: | 32 x 22 x 20 cm |
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Tessin habit quartz cluster. Photo taken in Himalayan Gems and Minerals, Pokhara, Nepal, by courtesy of Ms. Manandhar. |
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Mineral: Quartz Description: {100}, {210}, {101}, modified Location: Author: Presl, 1837. In: V.M. Goldschmidt, Atlas der Krystallformen, 1913-1923. System: Trigonal, point group: 32 Cell: a: 1, b: 1, c: 1.1, alpha: 90, beta: 90, gamma: 120 Link: http://www.smorf.nl/crystals_az_naam.php?crystal=Quartz_096 image@smorf
Note that Miller indices here omit the value of third trigonal axe |
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19801 Time(s) |
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