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Roger Warin
Joined: 23 Jan 2013
Posts: 1177
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Posted: Sep 15, 2013 08:54 Post subject: Euclase, an equant crystal |
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Hi,
Here is a good example of equant crystal of euclase. Origin: Gachala, Colombia.
Crystal system: monoclinic.
Unusual crystal habit, I think.
Can I hear from Pete? many thanks.
Roger.
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Euclase Gachala, Colombia 9 mm equant crystal |
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Mark Ost
Joined: 18 Mar 2013
Posts: 516
Location: Virginia Beach
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Posted: Sep 15, 2013 20:59 Post subject: Re: Euclase, an equant crysal |
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Roger. It is beautiful. Never seen anything like it.
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Roger Warin
Joined: 23 Jan 2013
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Posted: Sep 16, 2013 04:08 Post subject: Re: Euclase, an equant crysal |
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Hi List,
Here is probably the best euclase in the world.
It was exhibited for the first time in Munich Expo in 2002.
Roger Titeux told me it originated from Gachala, Colombia.
What do you think about?
Roger.
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Euclase Gachala, Colombia > 15 cm - I think |
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Pierre Joubert
Joined: 09 Mar 2012
Posts: 1605
Location: Western Cape
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Posted: Sep 16, 2013 04:18 Post subject: Re: Euclase, an equant crysal |
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Roger Warin wrote: | Hi List,
Here is probably the best euclase in the world.
It was exhibited for the first time in Munich Expo in 2002.
Roger Titeux told me it originated from Gachala, Colombia.
What do you think about?
Roger. |
Wow Roger!!!!!! Is this mind blowing specimen your's or your name sake's? If indeed your's, well done.
_________________ Pierre Joubert
'The tree of silence bears the fruit of peace. ' |
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
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Location: Barcelona
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Posted: Sep 16, 2013 04:19 Post subject: Re: Euclase, an equant crysal |
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Roger Warin wrote: | ....What do you think about? |
It exists another even better. Smaller, but unbroken.
Anyway, both are fabulous and yes, both came from Gachalá.
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Pete Richards
Site Admin
Joined: 29 Dec 2008
Posts: 828
Location: Northeast Ohio
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Posted: Sep 16, 2013 15:04 Post subject: Re: Euclase, an equant crysal |
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Roger Warin wrote: | Hi,
Here is a good example of equant crystal of euclase. Origin: Gachala, Colombia.
Crystal system: monoclinic.
Unusual crystal habit, I think.
Can I hear from Pete? many thanks.
Roger. |
If you mean me, Roger, I protest that I am not an expert on the habit of euclase, but I would say this is an unusual habit in my limited experience. None of the drawings in Goldschmidt are very similar to this one; most are of the typical prismatic habit like the other one you posted later.
_________________ Collecting and studying crystals with interesting habits, twinning, and epitaxy |
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
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Posted: Sep 16, 2013 15:17 Post subject: Re: Euclase, an equant crysal |
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Another example
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Euclase Piaotang Mine, Dayu, Jiangxi, China Specimen size: 3.4 × 1.9 × 1.8 cm Mined in 2007 Photo: Reference Specimens |
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Mark Ost
Joined: 18 Mar 2013
Posts: 516
Location: Virginia Beach
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Posted: Sep 16, 2013 18:22 Post subject: Re: Euclase, an equant crysal |
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OK Jordi....
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Martin Rich
Joined: 15 Aug 2013
Posts: 127
Location: Lower Austria
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Posted: Sep 16, 2013 19:49 Post subject: Re: Euclase, an equant crysal |
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In Alpine clefts, there occure sometimes Euclase with typical shape like in the first foto. I made a drawing similar to this fabolous blue crystal in the first foto.
Martin
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Euclase Euclase typical for Alpine clefts. |
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Fiebre Verde
Joined: 11 Sep 2013
Posts: 942
Location: Paris Area
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Posted: Sep 16, 2013 20:07 Post subject: Re: Euclase, an equant crysal |
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Another exceptional specimen made the cover page of the Mineralogical Record not long ago
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Fiebre Verde
Joined: 11 Sep 2013
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Location: Paris Area
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Posted: Sep 16, 2013 20:09 Post subject: Re: Euclase, an equant crysal |
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The MinRec specimen before trimming... looks slightly different!
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Roger Warin
Joined: 23 Jan 2013
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Posted: Sep 17, 2013 01:41 Post subject: Re: Euclase, an equant crysal |
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Hi Pete, Martin, and List,
Thank you for your opinions.
I never doubted the origin nor the identification of this euclase given by Roger Titeux, this extraordinary broker in mineralogy of high quality. He was a friend I regret the loss.
Thank Martin to show us a similar habit but still slightly different from my specimen.
Indeed, the blue of this stone is vivid, but blue is still poorly made by my camera that tends to make "electric" shades of blue. This camera is very sensitive in shades of blue-purple.
I use the Leica DFC 450 camera.
Roger.
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Martin Rich
Joined: 15 Aug 2013
Posts: 127
Location: Lower Austria
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Posted: Sep 17, 2013 15:00 Post subject: Re: Euclase, an equant crysal |
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Roger,
you are right, my drawing is only similar but I think this shape is not unusual. If you want to get sure, you have to make a goniometric measure.
Ok, I tryed it again but it is very hard from one single picture (sorry Roger, that I "killed" your wonderful photograph).
Martin
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Pete Richards
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Joined: 29 Dec 2008
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Location: Northeast Ohio
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Posted: Sep 17, 2013 15:52 Post subject: Re: Euclase, an equant crysal |
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Martin Rich wrote: | Roger,
you are right, my drawing is only similar but I think this shape is not unusual. If you want to get sure, you have to make a goniometric measure.
Ok, I tryed it again but it is very hard from one single picture (sorry Roger, that I "killed" your wonderful photograph).
Martin |
Well done, Martin! I suspect the areas marked ? may be areas of abrasion.
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Martin Rich
Joined: 15 Aug 2013
Posts: 127
Location: Lower Austria
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Posted: Sep 17, 2013 20:40 Post subject: Re: Euclase, an equant crysal |
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Pete Richards wrote: |
Well done, Martin! I suspect the areas marked ? may be areas of abrasion. |
Thank you Pete!
I think also this areas are of abrasion. The image is not very clear, so I post only the drawing again.
Martin
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Roger Warin
Joined: 23 Jan 2013
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Posted: Sep 18, 2013 03:35 Post subject: Re: Euclase, an equant crysal |
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Hi Martin, Pete,
Thank you for this very interesting discussion.
Thank you for this beautiful drawing. Your best fitting is correct.
Here are three new pics.
I don’t think this is an abrasion that changes the face (?), but maybe it’s a stop of growth or a dissolution. Small crystal imperfections are aligned.
What do you think?
Roger.
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Euclase Gachala, Colombia another orientation |
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Pete Richards
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Posted: Sep 18, 2013 07:37 Post subject: Re: Euclase, an equant crysal |
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Roger Warin wrote: | Hi Martin, Pete,
I don’t think this is an abrasion that changes the face (?), but maybe it’s a stop of growth or a dissolution. Small crystal imperfections are aligned.
What do you think?
Roger. |
Yes, on further thought, these "rounded" regions may be better explained by imperfections in growth or by dissolution. There are four equivalent regions on this crystal; your second image shows two of them. Are the other two also rounded? If the rounding were due to abarasion as e.g. by stream transport, one would think the steeper points at both ends would also be abraded, and that does not seem to be the case. In any event, the challenge is to understand why rounding is is confined to some parts of some edges and corners, and not seen on others.
Excellent images, Roger!
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Martin Rich
Joined: 15 Aug 2013
Posts: 127
Location: Lower Austria
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Posted: Sep 18, 2013 21:45 Post subject: Re: Euclase, an equant crysal |
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Roger, thank you for the excellent photographs, so I can see some more clear!
My last drawing (the red one) has some faults. {100} does not occur. I made new Miller indices for each face and I'm not sure if the shape {011} occures.
As supposed, this rounded shapes could be from dissolving. In my opinion there are two points according to a dissolving matter. 1st: not all edges and corners are affected. 2nd: Roger's last two photos are showing on the faces interesting cavities.
Martin
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Roger Warin
Joined: 23 Jan 2013
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Posted: Sep 19, 2013 08:40 Post subject: Re: Euclase, an equant crysal |
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Hi Martin,
Many thanks for this fine work.
Here are two pictures highlighting the faces {010} and {0-10}.
I think the face {100} is present. I'll try to photograph. It is very small.
Roger.
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Euclase Gachala, Colombia First side |
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Euclase Gachala, Colombia The second side |
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Pete Richards
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Posted: Sep 19, 2013 10:07 Post subject: Re: Euclase, an equant crysal |
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Until Roger's last two images I was uncomfortable with my understanding of the morphology and orientation of this crystal, but now I think I understand it. Attached is a SHAPE drawing with a different interpretation of the morphology from that of Martin. Roger, can you compare these drawings with your crystal and see if they seem correct?
One hint about the orientation of the crystal is that striations typically run parallel to the c-axis of euclase, another is that euclase has perfect cleavage parallel to {010}. Perhaps there are some minor cracks that reveal the direction of the cleavage?
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