| View previous topic :: View next topic |
| Author |
Message |
Josele
Joined: 10 Apr 2012
Posts: 410
Location: Tarifa, Spain
|
 Posted: Dec 27, 2012 09:42 Post subject: Waterclear mineral from Nepal? |
|
|
Recently I came back from Nepal, where I was trekking around the Annapurnas.
In Kathmandu I met Eric Manandhar, who is a Nepalese mineral dealer specialized in Ganesh Himal quartz. He was very pleasant and invited me to visit his home and to see his private collection. As many dealers do, he keeps the best specimens for his collection. He showed me some of the most fabulous quartz I've never seen.
Also he showed me a unknown waterclear mineral perched to a quartz that I can not identify. My first impression for color and luster was Topaz but, to me, the crystal looks as monoclinic or triclinic more than orthorhombic. Also Topaz is not listed in Ganesh Himal nor in Nepal Mindat gallery.
Perhaps you will can help us. Very thanks for your comment.
| Description: |
Unknown
Ganesh Himal, Nepal.
Crystal size: 8,1 x 4,3 x 1,3 cm
photo: Eric Manandhar |
|
| Viewed: |
42850 Time(s) |
|
| Description: |
Unknown
Ganesh Himal, Nepal.
Crystal size: 8,1 x 4,3 x 1,3 cm
photo: Eric Manandhar |
|
| Viewed: |
42874 Time(s) |
|
| Description: |
Unknown
Ganesh Himal, Nepal.
Crystal size: 8,1 x 4,3 x 1,3 cm
photo: Eric Manandhar |
|
| Viewed: |
42864 Time(s) |
|
| Description: |
Unknown
Ganesh Himal, Nepal.
Crystal size: 8,1 x 4,3 x 1,3 cm
photo: Eric Manandhar |
|
| Viewed: |
42919 Time(s) |
|
_________________
Josele |
|
| Back to top |
|
 |
Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 5022
Location: Barcelona
|
| Posted: Dec 27, 2012 10:00 Post subject: Re: Waterclear mineral from Nepal? |
|
|
| It could be an unusual crystal shape Quartz. By chance have you tested the hardness?
|
|
| Back to top |
|
|
Josele
Joined: 10 Apr 2012
Posts: 410
Location: Tarifa, Spain
|
| Posted: Dec 27, 2012 10:58 Post subject: Re: Waterclear mineral from Nepal? |
|
|
No, I had no chance to check any properties. Sorry, I can not offer more data, only these pictures.
But I had many quartzs in my hands that day and I think is not quartz.
_________________
Josele |
|
| Back to top |
|
|
Pierre Joubert
Joined: 09 Mar 2012
Posts: 1605
Location: Western Cape
|
| Posted: Dec 27, 2012 13:03 Post subject: Re: Waterclear mineral from Nepal? |
|
|
Josele, if it is quartz, it is quite unusual. I had a chance to look at your entry on Nepal in the Spanish forum. Fantastic!
_________________
Pierre Joubert
'The tree of silence bears the fruit of peace. ' |
|
| Back to top |
|
|
Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 842
Location: Northeast Ohio
|
| Posted: Dec 27, 2012 13:16 Post subject: Re: Waterclear mineral from Nepal? |
|
|
I believe this crystal is albite. A fine crystal to be sure!
_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy |
|
| Back to top |
|
|
vic rzonca
Joined: 18 Nov 2008
Posts: 820
Location: MA
|
| Posted: Dec 27, 2012 13:51 Post subject: Re: Waterclear mineral from Nepal? |
|
|
| Brilliant, Pete. Could it be the finest ever?
|
|
| Back to top |
|
|
Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 842
Location: Northeast Ohio
|
| Posted: Dec 27, 2012 18:00 Post subject: Re: Waterclear mineral from Nepal? |
|
|
| vic rzonca wrote: | | .... Could it be the finest ever? |
Well, I'm not experienced enough to make such extreme comparisons, but I've not seen an equally gemmy and well-formed crystal of albite larger than about 1/10 the size of that one....
_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy |
|
| Back to top |
|
|
Josele
Joined: 10 Apr 2012
Posts: 410
Location: Tarifa, Spain
|
| Posted: Dec 27, 2012 18:16 Post subject: Re: Waterclear mineral from Nepal? |
|
|
| Pete Richards wrote: | | I believe this crystal is albite. A fine crystal to be sure! |
| Pete Richards wrote: | | ... I've not seen an equally gemmy and well-formed crystal of albite larger than about 1/10 the size of that one.... |
Thank you very much Pete, was not easy...
Pete, sorry for abusing your wisdom: do you think is a single or a twin crystal?
Greetings.
| Description: |
| Albite {110}, {010}, {1-11}, modified |
|
| Viewed: |
42634 Time(s) |
|
| Description: |
| Albite {101}, {001}, {010}, modified |
|
| Viewed: |
42622 Time(s) |
|
_________________
Josele |
|
| Back to top |
|
|
Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 842
Location: Northeast Ohio
|
| Posted: Dec 27, 2012 19:14 Post subject: Re: Waterclear mineral from Nepal? |
|
|
| Josele wrote: | | Do you think this is a single or a twinned crystal? |
Although albite is very often twinned, this crystal appears not to be. The common twin law for albite is twinning parallel to the large {010} faces, sometimes just one twin, sometimes repeated twinning. Based on the very good images you sent, I do not see evidence of albite twinning (or any other mode of feldspar twinning, for that matter).
The habit of this crystal reminds me of those I've seen from certain alpine vein occurrences in Europe and Canada. The alpine vein setting might be reasonable for this crystal as well, though that is hard to know when you've just seen a crystal in a dealer's showroom!
_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy |
|
| Back to top |
|
|
Josele
Joined: 10 Apr 2012
Posts: 410
Location: Tarifa, Spain
|
| Posted: Dec 27, 2012 19:48 Post subject: Re: Waterclear mineral from Nepal? |
|
|
I think there is the first time that I see an albite single crystal! Pete, thanks for open my eyes.
Albite is a common partner of Ganesh Himal quartz. Here there is more material from the same find:
The photo below in high resolution
| Description: |
Quartz specimen showing Tessin habit prism and Dauphiné habit rhombohedral face. The lower and central section of the prism are included by chlorite* arborescences and rutile* needles, and in the middle-upper by some actinolite* or other amphibole needles. Albite and pericline law double twinned crystals attached to the bottom supports the set.
Ganesh Himal, Dhading District, Bagmati Zone, Nepal.
12 x 4 x 4 cm.
*just visually identified, not analyzed. |
|
| Viewed: |
42696 Time(s) |
|
_________________
Josele |
|
| Back to top |
|
|
Josele
Joined: 10 Apr 2012
Posts: 410
Location: Tarifa, Spain
|
| Posted: Dec 29, 2012 09:30 Post subject: Re: Waterclear mineral from Nepal? |
|
|
I tried to recognize the Miller indices on crystal faces. I assume that striations in front face are parallel to c axis.
Somebody can correct this?
Thanks for your help.
| Description: |
| Are Miller indices in right position? |
|
| Viewed: |
41685 Time(s) |
|
_________________
Josele |
|
| Back to top |
|
|
Riccardo Modanesi
Joined: 07 Nov 2011
Posts: 630
Location: Milano
|
| Posted: Dec 29, 2012 10:32 Post subject: Re: Waterclear mineral from Nepal? |
|
|
| Josele wrote: | No, I had no chance to check any properties. Sorry, I can not offer more data, only these pictures.
But I had many quartzs in my hands that day and I think is not quartz. |
Hi Josele and hi to everybody! I think we all must be sure about the hardness: if it is no lower than 6 (i.e. if it isn't scratched by an iron piece), it might be an albite. Without knowing the hardness, I can even think it is as low as 2, i.e. gypsum! Jordi, Carles and our Spanish friends know well there are beautiful gypsum crystals from Zaragoza appearing this shape!
Greetings from Italy by Riccardo.
_________________
Hi! I'm a collector of minerals since 1973 and a gemmologist. On Summer I always visit mines and quarries all over Europe looking for minerals! Ok, there is time to tell you much much more! Greetings from Italy by Riccardo. |
|
| Back to top |
|
|
Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 842
Location: Northeast Ohio
|
| Posted: Dec 29, 2012 12:29 Post subject: Re: Waterclear mineral from Nepal? |
|
|
It is very difficult to determine by eye the Miller Indices of faces on a crystal from a few pictures, especially a low-symmetry mineral like triclinic albite. Jose's choices are quite good - I think most of them are correct.
I drew an albite with SHAPE, which computes the geometry of a crystal in terms of its indices and its symmetry and unit cell, and correctly displays its form from any angle. This drawing seems to confirm most of Jose's choices. However, to get the crystal edge shown in red to have the right orientation relative to the rest of the edges, I had to use the indices -1-20 rather than -1-30. I also was not able to determine the indices for the little triangular face labeled -2-21, but those indices are incorrect.
By the way, the drawing uses the crystallographic convention of placing a line over a number that is negative, rather than putting the minus sign in front of it.
Jose, good job!
| Description: |
|
| Viewed: |
41703 Time(s) |
|
_________________
Collecting and studying crystals with interesting habits, twinning, and epitaxy |
|
| Back to top |
|
|
Josele
Joined: 10 Apr 2012
Posts: 410
Location: Tarifa, Spain
|
| Posted: Dec 29, 2012 19:48 Post subject: Re: Waterclear mineral from Nepal? |
|
|
Pete, very thanks for your help.
The small triangular face that I named mistakenly (-2-21), could be (-201)?
As you says, the face I named (-1-30) is (-1-20). Perhaps (-1-30) is the narrow bevel you can see at left in photo GH2.JPG?
Best regards.
| Description: |
|
| Viewed: |
41610 Time(s) |
|
_________________
Josele |
|
| Back to top |
|
|
Josele
Joined: 10 Apr 2012
Posts: 410
Location: Tarifa, Spain
|
| Posted: Dec 30, 2012 17:21 Post subject: Re: Waterclear mineral from Nepal? |
|
|
Today I received more pictures from Eric Manandhar and accurate measures of crystal size. Is bigger than that I noted by eye. The actual size is 8,1 x 4,3 x 1,3 cm.
Thanks for all comments and special thanks to Pete Richards for crystallographic help.
All photos © Eric Manandhar
| Description: |
Albite (crystallographically recognized, not analized)
8,1 x 4,3 x 1,3 cm
Ganesh Himal, Dhading District, Bagmati Zone, Nepal.
Side view from -b axis. |
|
| Viewed: |
41479 Time(s) |
|
| Description: |
|
| Viewed: |
41500 Time(s) |
|
| Description: |
| The shiny face can be (22-1). |
|
| Viewed: |
41465 Time(s) |
|
| Description: |
| Small polygonal faces of the corner can be (-221) and (-2-21). |
|
| Viewed: |
41468 Time(s) |
|
| Description: |
| Shiny face is (010). The narrow bevel at left can be (130). Striated face at left is (120) and hard left (110). |
|
| Viewed: |
41473 Time(s) |
|
| Description: |
| Shiny face can be (-111) with (-1-11) at right. |
|
| Viewed: |
41486 Time(s) |
|
| Description: |
| View from c axis. Shiny face can be (-111) and the narrow, very striated, even stepped face at right can be (001). Below, in the shade, (-1-11). |
|
| Viewed: |
41477 Time(s) |
|
| Description: |
Albite (crystallographically recognized, not analized)
8,1 x 4,3 x 1,3 cm
Ganesh Himal, Dhading District, Bagmati Zone, Nepal.
Very glassy. Where there is no striations can see fingerprints perfectly. |
|
| Viewed: |
41427 Time(s) |
|
_________________
Josele |
|
| Back to top |
|
|
|
FAQ 
Register
Log in
Forgotten your password?
